String.Compare 方法

参考

定义

命名空间:: System

程序集:: System.Runtime.dll

程序集:: mscorlib.dll

程序集:: netstandard.dll

重要

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比较两个指定的 String 对象，并返回一个指示二者在排序顺序中的相对位置的整数。

重载

Compare(String, Int32, String, Int32, Int32, CultureInfo, CompareOptions)	对两个指定 String 对象的子字符串进行比较，使用指定的比较选项和区域性特定的信息来影响比较，并返回一个整数，该整数指示这两个子字符串在排序顺序中的关系。
Compare(String, Int32, String, Int32, Int32, Boolean, CultureInfo)	比较两个指定的 String 对象（其中忽略或考虑其大小写，并使用区域性特定的信息干预比较），并返回一个整数，指示二者在排序顺序中的相对位置。
Compare(String, Int32, String, Int32, Int32, StringComparison)	使用指定的规则比较两个指定的 String 对象的子字符串，并返回一个整数，指示二者在排序顺序中的相对位置。
Compare(String, Int32, String, Int32, Int32, Boolean)	比较两个指定的 String 对象的子字符串（忽略或考虑其大小写），并返回一个整数，指示二者在排序顺序中的相对位置。
Compare(String, Int32, String, Int32, Int32)	比较两个指定的 String 对象的子字符串，并返回一个指示二者在排序顺序中的相对位置的整数。
Compare(String, String)	比较两个指定的 String 对象，并返回一个指示二者在排序顺序中的相对位置的整数。
Compare(String, String, Boolean, CultureInfo)	比较两个指定的 String 对象（其中忽略或考虑其大小写，并使用区域性特定的信息干预比较），并返回一个整数，指示二者在排序顺序中的相对位置。
Compare(String, String, StringComparison)	使用指定的规则比较两个指定的 String 对象，并返回一个整数，指示二者在排序顺序中的相对位置。
Compare(String, String, Boolean)	比较两个指定的 String 对象（其中忽略或考虑其大小写），并返回一个整数，指示二者在排序顺序中的相对位置。
Compare(String, String, CultureInfo, CompareOptions)	对两个指定的 String 对象进行比较，使用指定的比较选项和区域性特定的信息来影响比较，并返回一个整数，该整数指示这两个字符串在排序顺序中的关系。

注解

Compare 方法的所有重载返回一个 32 位有符号整数，指示两个比较数之间的词法关系。

“值”	条件
小于零	排序顺序中的第一个子字符串位于第二个子字符串之前。
零	子字符串在排序顺序中出现的位置相同或 `length` 为零。
大于零	第一个子字符串在排序顺序中紧跟第二个子字符串。

警告

应尽可能调用包含 StringComparison 参数的方法的Compare重载。有关详细信息，请参阅有关使用字符串的最佳实践。

Compare(String, Int32, String, Int32, Int32, CultureInfo, CompareOptions)

对两个指定 String 对象的子字符串进行比较，使用指定的比较选项和区域性特定的信息来影响比较，并返回一个整数，该整数指示这两个子字符串在排序顺序中的关系。

public:
 static int Compare(System::String ^ strA, int indexA, System::String ^ strB, int indexB, int length, System::Globalization::CultureInfo ^ culture, System::Globalization::CompareOptions options);

public static int Compare (string? strA, int indexA, string? strB, int indexB, int length, System.Globalization.CultureInfo? culture, System.Globalization.CompareOptions options);

public static int Compare (string strA, int indexA, string strB, int indexB, int length, System.Globalization.CultureInfo culture, System.Globalization.CompareOptions options);

static member Compare : string * int * string * int * int * System.Globalization.CultureInfo * System.Globalization.CompareOptions -> int

Public Shared Function Compare (strA As String, indexA As Integer, strB As String, indexB As Integer, length As Integer, culture As CultureInfo, options As CompareOptions) As Integer

参数

strA: String

要在比较中使用的第一个字符串。

indexA: Int32

strA 中子字符串开始的位置。

strB: String

要在比较中使用的第二个字符串。

indexB: Int32

strB 中子字符串开始的位置。

length: Int32

要比较的子字符串中字符的最大数量。

culture: CultureInfo

一个对象，提供区域性特定的比较信息。如果 culture 为 null，则使用当前区域性。

options: CompareOptions

要在执行比较时使用的选项（如忽略大小写或符号）。

Int32

一个整数，该整数用于指示两个子字符串之间的词法关系，如下表所示。

“值”	条件
小于零	`strA` 中的子字符串在排序顺序中位于 `strB` 中的子字符串之前。
零	子字符串在排序顺序中出现的位置相同或 `length` 为零。
大于零	`strA` 中的子字符串在排序顺序中位于 `strB` 中的子字符串之后。

例外

ArgumentException

options 不是 CompareOptions 值。

ArgumentOutOfRangeException

indexA 大于 strA.Length。

或

indexB 大于 strB.Length。

或

indexA、indexB 或 length 为负数。

或

strA 或 strB 为 null，并且 length 大于零。

示例

下面的示例使用 Compare(String, Int32, String, Int32, Int32, CultureInfo, CompareOptions) 方法比较两个人的姓氏。然后，它按字母顺序列出它们。

string name1 = "Jack Smith";
string name2 = "John Doe";

// Get position of character after the space character.
int index1 = name1.IndexOf(" ");
index1 = index1 < 0 ? 0 : ++index1;

int index2 = name2.IndexOf(" ");
index2 = index2 < 0 ? 0 : ++index2;

int length = Math.Max(name1.Length, name2.Length);

Console.WriteLine("Sorted alphabetically by last name:");
if (String.Compare(name1, index1, name2, index2, length,
                   new CultureInfo("en-US"), CompareOptions.IgnoreCase) < 0)
    Console.WriteLine("{0}\n{1}", name1, name2);
else
    Console.WriteLine("{0}\n{1}", name2, name1);

// The example displays the following output:
//       Sorted alphabetically by last name:
//       John Doe
//       Jack Smith

open System
open System.Globalization

let name1 = "Jack Smith"
let name2 = "John Doe"

// Get position of character after the space character.
let index1 =
    let i = name1.IndexOf " "
    if i < 0 then 0 else i + 1

let index2 = 
    let i = name2.IndexOf " "
    if i < 0 then 0 else i + 1

let length = max name1.Length name2.Length

printfn "Sorted alphabetically by last name:"
if String.Compare(name1, index1, name2, index2, length, CultureInfo "en-US", CompareOptions.IgnoreCase) < 0 then
    printfn $"{name1}\n{name2}"
else
    printfn $"{name2}\n{name1}"

// The example displays the following output:
//       Sorted alphabetically by last name:
//       John Doe
//       Jack Smith

Imports System.Globalization

Module Example
   Public Sub Main()
      Dim name1 As String = "Jack Smith"
      Dim name2 = "John Doe"
      
      ' Get position of space character.
      Dim index1 As Integer = name1.IndexOf(" ")
      index1 = CInt(IIf(index1 < 0, 0, index1 - 1))
      
      Dim index2 As Integer = name2.IndexOf(" ")
      index1 = CInt(IIf(index1 < 0, 0, index1 - 1))
      
      Dim length As Integer = Math.Max(name1.Length, name2.Length)
      
      Console.WriteLIne("Sorted alphabetically by last name:")
      If String.Compare(name1, index1, name2, index2, length, _
                        New CultureInfo("en-US"), CompareOptions.IgnoreCase) < 0 Then
         Console.WriteLine("{0}{1}{2}", name1, vbCrLf, name2)
      Else
         Console.WriteLine("{0}{1}{2}", name2, vbCrLf, name1)
      End If
   End Sub
End Module
' The example displays the following output;
'       Sorted alphabetically by last name:
'       John Doe
'       Jack Smith

注解

要比较的子字符串从位置开始strA，在 strB 位置indexAindexB处开始。第一个子字符串的长度是减去 indexA的strA长度。第二个子字符串的长度是减去 indexB的strB长度。

要比较的字符数是两个子字符串和 length的长度的较小。 indexA、 indexB和 length 参数必须是非否定的。

比较使用 culture 参数获取特定于区域性的信息，例如大小写规则和各个字符的字母顺序。例如，特定区域性可以指定将字符的某些组合视为单个字符，以特定方式比较大写和小写字符，或指定字符的排序顺序取决于字符前面或后面的字符。

注意

方法 Compare(String, Int32, String, Int32, Int32, CultureInfo, CompareOptions) 主要用于排序或按字母顺序排列操作。当方法调用的主要用途是确定两个子字符串是否等效 (即方法调用的目的是测试零) 的返回值时，不应使用此方法。若要确定两个字符串是否等效，请调用 Equals 方法。

和 strB 的strA一个或两者可以是 null。根据定义，任何字符串（包括 String.Empty）都会比较大于 null 引用，而两个 null 引用比较彼此相等。

可以通过参数进一步指定 options 比较，该参数由枚举的 System.Globalization.CompareOptions 一个或多个成员组成。但是，由于此方法的目的是执行区分区域性的字符串比较， CompareOptions.Ordinal 因此和 CompareOptions.OrdinalIgnoreCase 值不起作用。

当发现不相等或已比较两个子字符串时，比较终止。但是，如果两个字符串的比较等于一个字符串的末尾，而另一个字符串有剩余的字符，则具有剩余字符的字符串被视为更大。返回值是上次执行的比较的结果。

调用方说明

字符集包括可忽略字符。方法 Compare(String, Int32, String, Int32, Int32, CultureInfo, CompareOptions) 在执行语言或区分区域性的比较时不考虑这些字符。若要识别比较中的可忽略字符，请为 options 参数提供或 OrdinalIgnoreCase 值Ordinal。

另请参阅

Equals

适用于

Compare(String, Int32, String, Int32, Int32, Boolean, CultureInfo)

比较两个指定的 String 对象（其中忽略或考虑其大小写，并使用区域性特定的信息干预比较），并返回一个整数，指示二者在排序顺序中的相对位置。

public:
 static int Compare(System::String ^ strA, int indexA, System::String ^ strB, int indexB, int length, bool ignoreCase, System::Globalization::CultureInfo ^ culture);

public static int Compare (string? strA, int indexA, string? strB, int indexB, int length, bool ignoreCase, System.Globalization.CultureInfo? culture);

public static int Compare (string strA, int indexA, string strB, int indexB, int length, bool ignoreCase, System.Globalization.CultureInfo culture);

static member Compare : string * int * string * int * int * bool * System.Globalization.CultureInfo -> int

Public Shared Function Compare (strA As String, indexA As Integer, strB As String, indexB As Integer, length As Integer, ignoreCase As Boolean, culture As CultureInfo) As Integer

参数

strA: String

要在比较中使用的第一个字符串。

indexA: Int32

strA 中子字符串的位置。

strB: String

要在比较中使用的第二个字符串。

indexB: Int32

strB 中子字符串的位置。

length: Int32

要比较的子字符串中字符的最大数量。

ignoreCase: Boolean

若要在比较过程中忽略大小写，则为 true；否则为 false。

culture: CultureInfo

一个对象，提供区域性特定的比较信息。如果 culture 为 null，则使用当前区域性。

Int32

一个整数，指示两个比较字之间的词法关系。

“值”	条件
小于零	`strA` 中的子字符串在排序顺序中位于 `strB` 中的子字符串之前。
零	子字符串在排序顺序中出现的位置相同或 `length` 为零。
大于零	`strA` 中的子字符串在排序顺序中位于 `strB` 中的子字符串之后。

例外

ArgumentOutOfRangeException

indexA 大于 strA.Length。

或

indexB 大于 strB.Length。

或

indexA、indexB 或 length 为负数。

或

strA 或 strB 为 null，并且 length 大于零。

示例

以下示例使用不同区域性比较两个子字符串，并忽略子字符串大小写。区域性的选择会影响字母“I”的比较方式。

// Sample for String::Compare(String, Int32, String, Int32, Int32, Boolean, CultureInfo)
using namespace System;
using namespace System::Globalization;
int main()
{
   
   //                0123456
   String^ str1 = "MACHINE";
   String^ str2 = "machine";
   String^ str;
   int result;
   Console::WriteLine();
   Console::WriteLine( "str1 = '{0}', str2 = '{1}'", str1, str2 );
   Console::WriteLine( "Ignore case, Turkish culture:" );
   result = String::Compare( str1, 4, str2, 4, 2, true, gcnew CultureInfo( "tr-TR" ) );
   str = ((result < 0) ? "less than" : ((result > 0) ? (String^)"greater than" : "equal to"));
   Console::Write( "Substring '{0}' in '{1}' is ", str1->Substring( 4, 2 ), str1 );
   Console::Write( " {0} ", str );
   Console::WriteLine( "substring '{0}' in '{1}'.", str2->Substring( 4, 2 ), str2 );
   Console::WriteLine();
   Console::WriteLine( "Ignore case, invariant culture:" );
   result = String::Compare( str1, 4, str2, 4, 2, true, CultureInfo::InvariantCulture );
   str = ((result < 0) ? "less than" : ((result > 0) ? (String^)"greater than" : "equal to"));
   Console::Write( "Substring '{0}' in '{1}' is ", str1->Substring( 4, 2 ), str1 );
   Console::Write( " {0} ", str );
   Console::WriteLine( "substring '{0}' in '{1}'.", str2->Substring( 4, 2 ), str2 );
}

/*
This example produces the following results:

str1 = 'MACHINE', str2 = 'machine'
Ignore case, Turkish culture:
Substring 'IN' in 'MACHINE' is less than substring 'in' in 'machine'.

Ignore case, invariant culture:
Substring 'IN' in 'MACHINE' is equal to substring 'in' in 'machine'.
*/

// Sample for String.Compare(String, Int32, String, Int32, Int32, Boolean, CultureInfo)
using System;
using System.Globalization;

class Sample5
{
    public static void Main()
    {
        //                 0123456
        String str1 = "MACHINE";
        String str2 = "machine";
        String str;
        int result;

        Console.WriteLine();
        Console.WriteLine("str1 = '{0}', str2 = '{1}'", str1, str2);
        Console.WriteLine("Ignore case, Turkish culture:");
        result = String.Compare(str1, 4, str2, 4, 2, true, new CultureInfo("tr-TR"));
        str = ((result < 0) ? "less than" : ((result > 0) ? "greater than" : "equal to"));
        Console.Write("Substring '{0}' in '{1}' is ", str1.Substring(4, 2), str1);
        Console.Write("{0} ", str);
        Console.WriteLine("substring '{0}' in '{1}'.", str2.Substring(4, 2), str2);

        Console.WriteLine();
        Console.WriteLine("Ignore case, invariant culture:");
        result = String.Compare(str1, 4, str2, 4, 2, true, CultureInfo.InvariantCulture);
        str = ((result < 0) ? "less than" : ((result > 0) ? "greater than" : "equal to"));
        Console.Write("Substring '{0}' in '{1}' is ", str1.Substring(4, 2), str1);
        Console.Write("{0} ", str);
        Console.WriteLine("substring '{0}' in '{1}'.", str2.Substring(4, 2), str2);
    }
}
/*
This example produces the following results:

str1 = 'MACHINE', str2 = 'machine'
Ignore case, Turkish culture:
Substring 'IN' in 'MACHINE' is less than substring 'in' in 'machine'.

Ignore case, invariant culture:
Substring 'IN' in 'MACHINE' is equal to substring 'in' in 'machine'.
*/

// Sample for String.Compare(String, Int32, String, Int32, Int32, Boolean, CultureInfo)
open System
open System.Globalization

//                 0123456
let str1 = "MACHINE"
let str2 = "machine"

printfn $"\nstr1 = '{str1}', str2 = '{str2}'"
printfn "Ignore case, Turkish culture:"
let result = String.Compare(str1, 4, str2, 4, 2, true, CultureInfo "tr-TR")
let str = if result < 0 then "less than" elif result > 0 then "greater than" else "equal to"
printf $"Substring '{str1.Substring(4, 2)}' in '{str1}' is "
printf $"{str} "
printfn $"substring '{str2.Substring(4, 2)}' in '{str2}'."

printfn "\nIgnore case, invariant culture:"
let result2 = String.Compare(str1, 4, str2, 4, 2, true, CultureInfo.InvariantCulture)
let str3 = if result < 0 then "less than" elif result > 0 then "greater than" else "equal to"
printf $"Substring '{str1.Substring(4, 2)}' in '{str1}' is "
printf $"{str3} "
printfn $"substring '{str2.Substring(4, 2)}' in '{str2}'."

(*
This example produces the following results:

str1 = 'MACHINE', str2 = 'machine'
Ignore case, Turkish culture:
Substring 'IN' in 'MACHINE' is less than substring 'in' in 'machine'.

Ignore case, invariant culture:
Substring 'IN' in 'MACHINE' is equal to substring 'in' in 'machine'.
*)

' Sample for String.Compare(String, Int32, String, Int32, Int32, Boolean, CultureInfo)
Imports System.Globalization

Class Sample
   
   Public Shared Sub Main()
      '                       0123456
      Dim str1 As [String] = "MACHINE"
      Dim str2 As [String] = "machine"
      Dim str As [String]
      Dim result As Integer
      
      Console.WriteLine()
      Console.WriteLine("str1 = '{0}', str2 = '{1}'", str1, str2)
      Console.WriteLine("Ignore case, Turkish culture:")
      result = [String].Compare(str1, 4, str2, 4, 2, True, New CultureInfo("tr-TR"))
      str = IIf(result < 0, "less than", IIf(result > 0, "greater than", "equal to"))
      Console.Write("Substring '{0}' in '{1}' is ", str1.Substring(4, 2), str1)
      Console.Write("{0} ", str)
      Console.WriteLine("substring '{0}' in '{1}'.", str2.Substring(4, 2), str2)
      
      Console.WriteLine()
      Console.WriteLine("Ignore case, invariant culture:")
      result = [String].Compare(str1, 4, str2, 4, 2, True, CultureInfo.InvariantCulture)
      str = IIf(result < 0, "less than", IIf(result > 0, "greater than", "equal to"))
      Console.Write("Substring '{0}' in '{1}' is ", str1.Substring(4, 2), str1)
      Console.Write("{0} ", str)
      Console.WriteLine("substring '{0}' in '{1}'.", str2.Substring(4, 2), str2)
   End Sub
End Class
'
'This example produces the following results:
'
'str1 = 'MACHINE', str2 = 'machine'
'Ignore case, Turkish culture:
'Substring 'IN' in 'MACHINE' is less than substring 'in' in 'machine'.
'
'Ignore case, invariant culture:
'Substring 'IN' in 'MACHINE' is equal to substring 'in' in 'machine'.
'

注解

要比较的子字符串从开始strAindexA，在 strB 处indexB开始。和 indexB 都是indexA从零开始的;也就是说，和 strB 中的strA第一个字符位于位置 0，而不是位置 1。第一个子字符串的长度等于减去 indexA 1 的strA长度。第二个子字符串的长度等于减去 indexB 1 的strB长度。

要比较的字符数是两个子字符串和 length的长度的较小。 indexA、 indexB和 length 参数必须是非否定的。

比较使用 culture 参数获取特定于区域性的信息，例如大小写规则和单个字符的字母顺序。例如，区域性可以指定将字符的某些组合视为单个字符，或者以特定方式比较大写和小写字符，或者指定字符的排序顺序取决于字符前面或后面的字符。

比较是使用单词排序规则执行的。有关单词、字符串和序号排序的详细信息，请参阅 System.Globalization.CompareOptions。

一个或两个比较可以是 null。根据定义，任何字符串（包括空字符串 (“”) ）都比较大于 null 引用;和两个 null 引用相等比较。

当发现不相等或已比较两个子字符串时，比较终止。但是，如果两个字符串的比较等于一个字符串的末尾，而另一个字符串的剩余字符，则认为具有剩余字符的字符串更大。返回值是上次执行的比较的结果。

当比较受到区域性特定大小写规则的影响时，可能会出现意外结果。例如，在土耳其语中，以下示例生成错误的结果，因为土耳其语中的文件系统未对“file”中的字母“i”使用语言大小写规则。

static bool IsFileURI(String^ path)
{
    return (String::Compare(path, 0, "file:", 0, 5, true) == 0);
}

static bool IsFileURI(String path)
{
    return (String.Compare(path, 0, "file:", 0, 5, true) == 0);
}

let isFileURI path =
    String.Compare(path, 0, "file:", 0, 5, true) = 0

Shared Function IsFileURI(ByVal path As String) As Boolean
    If String.Compare(path, 0, "file:", 0, 5, True) = 0 Then
        Return True
    Else
        Return False
    End If
End Function

使用序号比较将路径名与“文件”进行比较。执行此操作的正确代码如下所示：

static bool IsFileURI(String^ path)
{
    return (String::Compare(path, 0, "file:", 0, 5, StringComparison::OrdinalIgnoreCase) == 0);
}

static bool IsFileURI(String path)
{
    return (String.Compare(path, 0, "file:", 0, 5, StringComparison.OrdinalIgnoreCase) == 0);
}

let isFileURI path =
    String.Compare(path, 0, "file:", 0, 5, StringComparison.OrdinalIgnoreCase) = 0

Shared Function IsFileURI(ByVal path As String) As Boolean
    If String.Compare(path, 0, "file:", 0, 5, StringComparison.OrdinalIgnoreCase) = 0 Then
        Return True
    Else
        Return False
    End If
End Function

调用方说明

字符集包括可忽略字符。方法 Compare(String, Int32, String, Int32, Int32, Boolean, CultureInfo) 在执行语言或区分区域性的比较时不考虑这些字符。若要识别比较中的可忽略字符，请调用 Compare(String, Int32, String, Int32, Int32, CultureInfo, CompareOptions) 方法并为参数提供或 OrdinalIgnoreCaseoptions 值Ordinal。

另请参阅

适用于

Compare(String, Int32, String, Int32, Int32, StringComparison)

使用指定的规则比较两个指定的 String 对象的子字符串，并返回一个整数，指示二者在排序顺序中的相对位置。

public:
 static int Compare(System::String ^ strA, int indexA, System::String ^ strB, int indexB, int length, StringComparison comparisonType);

public static int Compare (string strA, int indexA, string strB, int indexB, int length, StringComparison comparisonType);

public static int Compare (string? strA, int indexA, string? strB, int indexB, int length, StringComparison comparisonType);

static member Compare : string * int * string * int * int * StringComparison -> int

Public Shared Function Compare (strA As String, indexA As Integer, strB As String, indexB As Integer, length As Integer, comparisonType As StringComparison) As Integer

参数

strA: String

要在比较中使用的第一个字符串。

indexA: Int32

strA 中子字符串的位置。

strB: String

要在比较中使用的第二个字符串。

indexB: Int32

strB 中子字符串的位置。

length: Int32

要比较的子字符串中字符的最大数量。

comparisonType: StringComparison

一个枚举值，用于指定比较中要使用的规则。

Int32

一个 32 位带符号整数，指示两个比较数之间的词法关系。

“值”	条件
小于零	`strA` 中的子字符串在排序顺序中位于 `strB` 中的子字符串之前。
零	子字符串在排序顺序中出现的位置相同，或 `length` 参数为零。
大于零	`strA` 中的子字符串在排序顺序中位于 `strB` 中的子字符串之后。

例外

ArgumentOutOfRangeException

indexA 大于 strA.Length。

或

indexB 大于 strB.Length。

或

indexA、indexB 或 length 为负数。

或

indexA 或 indexB 为 null，并且 length 大于零。

ArgumentException

comparisonType 不是 StringComparison 值。

示例

以下示例比较两个子字符串。

// Sample for String::Compare(String, Int32, String, Int32, Int32)
using namespace System;
int main()
{
   
   //                0123456
   String^ str1 = "machine";
   String^ str2 = "device";
   String^ str;
   int result;
   Console::WriteLine();
   Console::WriteLine( "str1 = '{0}', str2 = '{1}'", str1, str2 );
   result = String::Compare( str1, 2, str2, 0, 2 );
   str = ((result < 0) ? "less than" : ((result > 0) ? (String^)"greater than" : "equal to"));
   Console::Write( "Substring '{0}' in ' {1}' is ", str1->Substring( 2, 2 ), str1 );
   Console::Write( " {0} ", str );
   Console::WriteLine( "substring '{0}' in ' {1}'.", str2->Substring( 0, 2 ), str2 );
}

/*
This example produces the following results:

str1 = 'machine', str2 = 'device'
Substring 'ch' in 'machine' is less than substring 'de' in 'device'.
*/

String str1 = "machine";
String str2 = "device";
String str;
int result;

Console.WriteLine();
Console.WriteLine("str1 = '{0}', str2 = '{1}'", str1, str2);
result = String.Compare(str1, 2, str2, 0, 2);
str = ((result < 0) ? "less than" : ((result > 0) ? "greater than" : "equal to"));
Console.Write("Substring '{0}' in '{1}' is ", str1.Substring(2, 2), str1);
Console.Write("{0} ", str);
Console.WriteLine("substring '{0}' in '{1}'.", str2.Substring(0, 2), str2);

/*
This example produces the following results:

str1 = 'machine', str2 = 'device'
Substring 'ch' in 'machine' is less than substring 'de' in 'device'.
*/

open System

let str1 = "machine"
let str2 = "device"

printfn "\nstr1 = '{str1}', str2 = '{str2}'"

let result = String.Compare(str1, 2, str2, 0, 2)
let str = 
    if result < 0 then "less than" 
    elif result > 0 then "greater than" 
    else "equal to"

printf $"Substring '{str1.Substring(2, 2)}' in '{str1}' is "
printf $"{str} "
printfn $"substring '{str2.Substring(0, 2)}' in '{str2}'."

(*
This example produces the following results:

str1 = 'machine', str2 = 'device'
Substring 'ch' in 'machine' is less than substring 'de' in 'device'.
*)

' Sample for String.Compare(String, Int32, String, Int32, Int32)
Class Sample
   Public Shared Sub Main()
      '                       0123456
      Dim str1 As [String] = "machine"
      Dim str2 As [String] = "device"
      Dim str As [String]
      Dim result As Integer
      
      Console.WriteLine()
      Console.WriteLine("str1 = '{0}', str2 = '{1}'", str1, str2)
      result = [String].Compare(str1, 2, str2, 0, 2)
      str = IIf(result < 0, "less than", IIf(result > 0, "greater than", "equal to"))
      Console.Write("Substring '{0}' in '{1}' is ", str1.Substring(2, 2), str1)
      Console.Write("{0} ", str)
      Console.WriteLine("substring '{0}' in '{1}'.", str2.Substring(0, 2), str2)
   End Sub
End Class
'
'This example produces the following results:
'
'str1 = 'machine', str2 = 'device'
'Substring 'ch' in 'machine' is less than substring 'de' in 'device'.
'

注解

要比较的子字符串从中strAindexA开始，在 strB 处indexB开始。和 indexB 都是indexA从零开始的;也就是说，中的strAstrB第一个字符位于位置零，而不是位置 1。第一个子字符串的长度等于减号indexA加 1 的strA长度。第二个子字符串的长度等于减去 indexB 1 的strB长度。

要比较的字符数是两个子字符串和 length的长度的较小。 indexA、 indexB和 length 参数必须是非否定的。

参数 comparisonType 指示比较是应使用当前区域性还是固定区域性、遵循或忽略比较大小写，还是使用区分区域性的单词 () 或序号 (不区分区域性) 排序规则。

一个或两个比较可以是 null。根据定义，任何字符串（包括空字符串 (“”) ）都比较大于 null 引用;和两个 null 引用相等比较。

static bool IsFileURI(String^ path)
{
    return (String::Compare(path, 0, "file:", 0, 5, true) == 0);
}

static bool IsFileURI(String path)
{
    return (String.Compare(path, 0, "file:", 0, 5, true) == 0);
}

let isFileURI path =
    String.Compare(path, 0, "file:", 0, 5, true) = 0

Shared Function IsFileURI(ByVal path As String) As Boolean
    If String.Compare(path, 0, "file:", 0, 5, True) = 0 Then
        Return True
    Else
        Return False
    End If
End Function

使用序号比较将路径名与“文件”进行比较。执行此操作的正确代码如下所示：

static bool IsFileURI(String^ path)
{
    return (String::Compare(path, 0, "file:", 0, 5, StringComparison::OrdinalIgnoreCase) == 0);
}

static bool IsFileURI(String path)
{
    return (String.Compare(path, 0, "file:", 0, 5, StringComparison.OrdinalIgnoreCase) == 0);
}

let isFileURI path =
    String.Compare(path, 0, "file:", 0, 5, StringComparison.OrdinalIgnoreCase) = 0

Shared Function IsFileURI(ByVal path As String) As Boolean
    If String.Compare(path, 0, "file:", 0, 5, StringComparison.OrdinalIgnoreCase) = 0 Then
        Return True
    Else
        Return False
    End If
End Function

调用方说明

字符集包括可忽略字符。方法 Compare(String, Int32, String, Int32, Int32, StringComparison) 在执行语言或区域性敏感比较时不考虑这些字符。若要识别比较中的可忽略字符，请为 comparisonType 参数提供或 OrdinalIgnoreCase 值Ordinal。

另请参阅

适用于

Compare(String, Int32, String, Int32, Int32, Boolean)

比较两个指定的 String 对象的子字符串（忽略或考虑其大小写），并返回一个整数，指示二者在排序顺序中的相对位置。

public:
 static int Compare(System::String ^ strA, int indexA, System::String ^ strB, int indexB, int length, bool ignoreCase);

public static int Compare (string? strA, int indexA, string? strB, int indexB, int length, bool ignoreCase);

public static int Compare (string strA, int indexA, string strB, int indexB, int length, bool ignoreCase);

static member Compare : string * int * string * int * int * bool -> int

Public Shared Function Compare (strA As String, indexA As Integer, strB As String, indexB As Integer, length As Integer, ignoreCase As Boolean) As Integer

参数

strA: String

要在比较中使用的第一个字符串。

indexA: Int32

strA 中子字符串的位置。

strB: String

要在比较中使用的第二个字符串。

indexB: Int32

strB 中子字符串的位置。

length: Int32

要比较的子字符串中字符的最大数量。

ignoreCase: Boolean

若要在比较过程中忽略大小写，则为 true；否则为 false。

Int32

一个 32 位带符号整数，指示两个比较数之间的词法关系。

“值”	条件
小于零	`strA` 中的子字符串在排序顺序中位于 `strB` 中的子字符串之前。
零	子字符串在排序顺序中出现的位置相同或 `length` 为零。
大于零	`strA` 中的子字符串在排序顺序中位于 `strB` 中的子字符串之后。

例外

ArgumentOutOfRangeException

indexA 大于 strA.Length。

或

indexB 大于 strB.Length。

或

indexA、indexB 或 length 为负数。

或

indexA 或 indexB 为 null，并且 length 大于零。

示例

以下示例对两个子字符串执行两次比较，这些子字符串仅在大小写上不同。第一个比较忽略大小写，第二个比较将考虑大小写。

// Sample for String::Compare(String, Int32, String, Int32, Int32, Boolean)
using namespace System;
int main()
{
   
   //                0123456
   String^ str1 = "MACHINE";
   String^ str2 = "machine";
   String^ str;
   int result;
   Console::WriteLine();
   Console::WriteLine( "str1 = '{0}', str2 = '{1}'", str1, str2 );
   Console::WriteLine( "Ignore case:" );
   result = String::Compare( str1, 2, str2, 2, 2, true );
   str = ((result < 0) ? "less than" : ((result > 0) ? (String^)"greater than" : "equal to"));
   Console::Write( "Substring '{0}' in '{1}' is ", str1->Substring( 2, 2 ), str1 );
   Console::Write( " {0} ", str );
   Console::WriteLine( "substring '{0}' in '{1}'.", str2->Substring( 2, 2 ), str2 );
   Console::WriteLine();
   Console::WriteLine( "Honor case:" );
   result = String::Compare( str1, 2, str2, 2, 2, false );
   str = ((result < 0) ? "less than" : ((result > 0) ? (String^)"greater than" : "equal to"));
   Console::Write( "Substring '{0}' in '{1}' is ", str1->Substring( 2, 2 ), str1 );
   Console::Write( " {0} ", str );
   Console::WriteLine( "substring '{0}' in '{1}'.", str2->Substring( 2, 2 ), str2 );
}

/*
This example produces the following results:

str1 = 'MACHINE', str2 = 'machine'
Ignore case:
Substring 'CH' in 'MACHINE' is equal to substring 'ch' in 'machine'.

Honor case:
Substring 'CH' in 'MACHINE' is greater than substring 'ch' in 'machine'.
*/

String str1 = "MACHINE";
String str2 = "machine";
String str;
int result;

Console.WriteLine();
Console.WriteLine("str1 = '{0}', str2 = '{1}'", str1, str2);

Console.WriteLine("Ignore case:");
result = String.Compare(str1, 2, str2, 2, 2, true);
str = ((result < 0) ? "less than" : ((result > 0) ? "greater than" : "equal to"));
Console.Write("Substring '{0}' in '{1}' is ", str1.Substring(2, 2), str1);
Console.Write("{0} ", str);
Console.WriteLine("substring '{0}' in '{1}'.", str2.Substring(2, 2), str2);
Console.WriteLine();

Console.WriteLine("Honor case:");
result = String.Compare(str1, 2, str2, 2, 2, false);
str = ((result < 0) ? "less than" : ((result > 0) ? "greater than" : "equal to"));
Console.Write("Substring '{0}' in '{1}' is ", str1.Substring(2, 2), str1);
Console.Write("{0} ", str);
Console.WriteLine("substring '{0}' in '{1}'.", str2.Substring(2, 2), str2);

/*
This example produces the following results:

str1 = 'MACHINE', str2 = 'machine'
Ignore case:
Substring 'CH' in 'MACHINE' is equal to substring 'ch' in 'machine'.

Honor case:
Substring 'CH' in 'MACHINE' is greater than substring 'ch' in 'machine'.
*/

open System

let str1 = "MACHINE"
let str2 = "machine"

printfn $"\nstr1 = '{str1}', str2 = '{str2}'"

printfn "Ignore case:"
let result = String.Compare(str1, 2, str2, 2, 2, true)
let str = 
    if result < 0 then "less than" 
    elif result > 0 then "greater than"
    else "equal to"

printf $"Substring '{str1.Substring(2, 2)}' in '{str1}' is "
printf $"{str} "
printfn $"substring '{str2.Substring(2, 2)}' in '{str2}'.\n"

printfn "Honor case:"
let result2 = String.Compare(str1, 2, str2, 2, 2, false)
let str3 = 
    if result < 0 then "less than" 
    elif result > 0 then "greater than" 
    else "equal to"

printfn $"Substring '{str1.Substring(2, 2)}' in '{str1}' is "
printf $"{str3} "
printfn $"substring '{str2.Substring(2, 2)}' in '{str2}'."

(*
This example produces the following results:

str1 = 'MACHINE', str2 = 'machine'
Ignore case:
Substring 'CH' in 'MACHINE' is equal to substring 'ch' in 'machine'.

Honor case:
Substring 'CH' in 'MACHINE' is greater than substring 'ch' in 'machine'.
*)

' Sample for String.Compare(String, Int32, String, Int32, Int32, Boolean)
Class Sample
   
   Public Shared Sub Main()
      '                       0123456
      Dim str1 As [String] = "MACHINE"
      Dim str2 As [String] = "machine"
      Dim str As [String]
      Dim result As Integer
      
      Console.WriteLine()
      Console.WriteLine("str1 = '{0}', str2 = '{1}'", str1, str2)
      Console.WriteLine("Ignore case:")
      result = [String].Compare(str1, 2, str2, 2, 2, True)
      str = IIf(result < 0, "less than", IIf(result > 0, "greater than", "equal to"))
      Console.Write("Substring '{0}' in '{1}' is ", str1.Substring(2, 2), str1)
      Console.Write("{0} ", str)
      Console.WriteLine("substring '{0}' in '{1}'.", str2.Substring(2, 2), str2)
      
      Console.WriteLine()
      Console.WriteLine("Honor case:")
      result = [String].Compare(str1, 2, str2, 2, 2, False)
      str = IIf(result < 0, "less than", IIf(result > 0, "greater than", "equal to"))
      Console.Write("Substring '{0}' in '{1}' is ", str1.Substring(2, 2), str1)
      Console.Write("{0} ", str)
      Console.WriteLine("substring '{0}' in '{1}'.", str2.Substring(2, 2), str2)
   End Sub
End Class
'
'This example produces the following results:
'
'str1 = 'MACHINE', str2 = 'machine'
'Ignore case:
'Substring 'CH' in 'MACHINE' is equal to substring 'ch' in 'machine'.
'
'Honor case:
'Substring 'CH' in 'MACHINE' is greater than substring 'ch' in 'machine'.
'

注解

要比较的子字符串从中strAindexA开始，在处strBindexB开始。和 indexB 都是indexA从零开始的;也就是说，中的strAstrB第一个字符位于位置零。第一个子字符串的长度等于减号indexA加 1 的strA长度。第二个子字符串的长度等于减去 indexB 1 的strB长度。

要比较的字符数是两个子字符串和 length的长度的较小。 indexA、 indexB和 length 参数必须是非否定的。

比较使用当前区域性来获取特定于区域性的信息，例如大小写规则和单个字符的字母顺序。例如，区域性可以指定将字符的某些组合视为单个字符，或者以特定方式比较大写和小写字符，或者字符的排序顺序取决于其前面或后面的字符。

比较是使用单词排序规则执行的。有关单词、字符串和序号排序的详细信息，请参阅 System.Globalization.CompareOptions。

警告

比较字符串时，应调用 Compare(String, Int32, String, Int32, Int32, StringComparison) 方法，这要求显式指定该方法使用的字符串比较类型。有关详细信息，请参阅有关使用字符串的最佳实践。

一个或两个比较可以是 null。根据定义，任何字符串（包括空字符串 (“”) ）都比较大于 null 引用;和两个 null 引用相等比较。

static bool IsFileURI(String^ path)
{
    return (String::Compare(path, 0, "file:", 0, 5, true) == 0);
}

static bool IsFileURI(String path)
{
    return (String.Compare(path, 0, "file:", 0, 5, true) == 0);
}

let isFileURI path =
    String.Compare(path, 0, "file:", 0, 5, true) = 0

Shared Function IsFileURI(ByVal path As String) As Boolean
    If String.Compare(path, 0, "file:", 0, 5, True) = 0 Then
        Return True
    Else
        Return False
    End If
End Function

需要以固定方式比较路径名称。执行此操作的正确代码如下所示。

static bool IsFileURI(String^ path)
{
    return (String::Compare(path, 0, "file:", 0, 5, StringComparison::OrdinalIgnoreCase) == 0);
}

static bool IsFileURI(String path)
{
    return (String.Compare(path, 0, "file:", 0, 5, StringComparison.OrdinalIgnoreCase) == 0);
}

let isFileURI path =
    String.Compare(path, 0, "file:", 0, 5, StringComparison.OrdinalIgnoreCase) = 0

Shared Function IsFileURI(ByVal path As String) As Boolean
    If String.Compare(path, 0, "file:", 0, 5, StringComparison.OrdinalIgnoreCase) = 0 Then
        Return True
    Else
        Return False
    End If
End Function

调用方说明

字符集包括可忽略字符。方法 Compare(String, Int32, String, Int32, Int32, Boolean) 在执行语言或区域性敏感比较时不考虑这些字符。若要识别比较中的可忽略字符，请调用 Compare(String, Int32, String, Int32, Int32, StringComparison) 方法并为参数提供或 OrdinalIgnoreCasecomparisonType 值Ordinal。

另请参阅

适用于

Compare(String, Int32, String, Int32, Int32)

比较两个指定的 String 对象的子字符串，并返回一个指示二者在排序顺序中的相对位置的整数。

public:
 static int Compare(System::String ^ strA, int indexA, System::String ^ strB, int indexB, int length);

public static int Compare (string strA, int indexA, string strB, int indexB, int length);

public static int Compare (string? strA, int indexA, string? strB, int indexB, int length);

static member Compare : string * int * string * int * int -> int

Public Shared Function Compare (strA As String, indexA As Integer, strB As String, indexB As Integer, length As Integer) As Integer

参数

strA: String

要在比较中使用的第一个字符串。

indexA: Int32

strA 中子字符串的位置。

strB: String

要在比较中使用的第二个字符串。

indexB: Int32

strB 中子字符串的位置。

length: Int32

要比较的子字符串中字符的最大数量。

Int32

一个 32 位有符号整数，指示两个比较数之间的词法关系。

值	条件
小于零	`strA` 中的子字符串在排序顺序中位于 `strB` 中的子字符串之前。
零	子字符串在排序顺序中出现的位置相同或 `length` 为零。
大于零	`strA` 中的子字符串在排序顺序中位于 `strB` 中的子字符串之后。

例外

ArgumentOutOfRangeException

indexA 大于 strA.Length。

或

indexB 大于 strB.Length。

或

indexA、indexB 或 length 为负数。

或

indexA 或 indexB 为 null，并且 length 大于零。

示例

以下示例比较两个子字符串。

// Sample for String::Compare(String, Int32, String, Int32, Int32)
using namespace System;
int main()
{
   
   //                0123456
   String^ str1 = "machine";
   String^ str2 = "device";
   String^ str;
   int result;
   Console::WriteLine();
   Console::WriteLine( "str1 = '{0}', str2 = '{1}'", str1, str2 );
   result = String::Compare( str1, 2, str2, 0, 2 );
   str = ((result < 0) ? "less than" : ((result > 0) ? (String^)"greater than" : "equal to"));
   Console::Write( "Substring '{0}' in ' {1}' is ", str1->Substring( 2, 2 ), str1 );
   Console::Write( " {0} ", str );
   Console::WriteLine( "substring '{0}' in ' {1}'.", str2->Substring( 0, 2 ), str2 );
}

/*
This example produces the following results:

str1 = 'machine', str2 = 'device'
Substring 'ch' in 'machine' is less than substring 'de' in 'device'.
*/

String str1 = "machine";
String str2 = "device";
String str;
int result;

Console.WriteLine();
Console.WriteLine("str1 = '{0}', str2 = '{1}'", str1, str2);
result = String.Compare(str1, 2, str2, 0, 2);
str = ((result < 0) ? "less than" : ((result > 0) ? "greater than" : "equal to"));
Console.Write("Substring '{0}' in '{1}' is ", str1.Substring(2, 2), str1);
Console.Write("{0} ", str);
Console.WriteLine("substring '{0}' in '{1}'.", str2.Substring(0, 2), str2);

/*
This example produces the following results:

str1 = 'machine', str2 = 'device'
Substring 'ch' in 'machine' is less than substring 'de' in 'device'.
*/

open System

let str1 = "machine"
let str2 = "device"

printfn "\nstr1 = '{str1}', str2 = '{str2}'"

let result = String.Compare(str1, 2, str2, 0, 2)
let str = 
    if result < 0 then "less than" 
    elif result > 0 then "greater than" 
    else "equal to"

printf $"Substring '{str1.Substring(2, 2)}' in '{str1}' is "
printf $"{str} "
printfn $"substring '{str2.Substring(0, 2)}' in '{str2}'."

(*
This example produces the following results:

str1 = 'machine', str2 = 'device'
Substring 'ch' in 'machine' is less than substring 'de' in 'device'.
*)

' Sample for String.Compare(String, Int32, String, Int32, Int32)
Class Sample
   Public Shared Sub Main()
      '                       0123456
      Dim str1 As [String] = "machine"
      Dim str2 As [String] = "device"
      Dim str As [String]
      Dim result As Integer
      
      Console.WriteLine()
      Console.WriteLine("str1 = '{0}', str2 = '{1}'", str1, str2)
      result = [String].Compare(str1, 2, str2, 0, 2)
      str = IIf(result < 0, "less than", IIf(result > 0, "greater than", "equal to"))
      Console.Write("Substring '{0}' in '{1}' is ", str1.Substring(2, 2), str1)
      Console.Write("{0} ", str)
      Console.WriteLine("substring '{0}' in '{1}'.", str2.Substring(0, 2), str2)
   End Sub
End Class
'
'This example produces the following results:
'
'str1 = 'machine', str2 = 'device'
'Substring 'ch' in 'machine' is less than substring 'de' in 'device'.
'

注解

要比较的子字符串从中strAindexA开始，在 strB 处indexB开始。和 indexB 都是indexA从零开始的;也就是说，中的strAstrB第一个字符位于位置零。第一个子字符串的长度等于减号indexA加 1 的strA长度。第二个子字符串的长度等于减去 indexB 1 的strB长度。

要比较的字符数是两个子字符串和 length的长度的较小。 indexA、 indexB和 length 参数必须是非否定的。

比较是使用单词排序规则执行的。有关单词、字符串和序号排序的详细信息，请参阅 System.Globalization.CompareOptions。

警告

一个或两个比较可以是 null。根据定义，任何字符串（包括空字符串 (“”) ）都比较大于 null 引用;和两个 null 引用相等比较。

static bool IsFileURI(String^ path)
{
    return (String::Compare(path, 0, "file:", 0, 5, true) == 0);
}

static bool IsFileURI(String path)
{
    return (String.Compare(path, 0, "file:", 0, 5, true) == 0);
}

let isFileURI path =
    String.Compare(path, 0, "file:", 0, 5, true) = 0

Shared Function IsFileURI(ByVal path As String) As Boolean
    If String.Compare(path, 0, "file:", 0, 5, True) = 0 Then
        Return True
    Else
        Return False
    End If
End Function

使用序号比较将路径名与“文件”进行比较。执行此操作的正确代码如下所示：

static bool IsFileURI(String^ path)
{
    return (String::Compare(path, 0, "file:", 0, 5, StringComparison::OrdinalIgnoreCase) == 0);
}

static bool IsFileURI(String path)
{
    return (String.Compare(path, 0, "file:", 0, 5, StringComparison.OrdinalIgnoreCase) == 0);
}

let isFileURI path =
    String.Compare(path, 0, "file:", 0, 5, StringComparison.OrdinalIgnoreCase) = 0

Shared Function IsFileURI(ByVal path As String) As Boolean
    If String.Compare(path, 0, "file:", 0, 5, StringComparison.OrdinalIgnoreCase) = 0 Then
        Return True
    Else
        Return False
    End If
End Function

调用方说明

字符集包括可忽略字符。方法 Compare(String, Int32, String, Int32, Int32) 在执行语言或区域性敏感比较时不考虑这些字符。若要识别比较中的可忽略字符，请调用 Compare(String, Int32, String, Int32, Int32, StringComparison) 方法并为参数提供或 OrdinalIgnoreCasecomparisonType 值Ordinal。

另请参阅

适用于

Compare(String, String)

比较两个指定的 String 对象，并返回一个指示二者在排序顺序中的相对位置的整数。

public:
 static int Compare(System::String ^ strA, System::String ^ strB);

public static int Compare (string strA, string strB);

public static int Compare (string? strA, string? strB);

static member Compare : string * string -> int

Public Shared Function Compare (strA As String, strB As String) As Integer

参数

strA: String

要比较的第一个字符串。

strB: String

要比较的第二个字符串。

Int32

一个 32 位带符号整数，指示两个比较数之间的词法关系。

“值”	条件
小于零	`strA` 在排序顺序中位于 `strB` 之前。
零	`strA` 与 `strB` 在排序顺序中出现的位置相同。
大于零	`strA` 在排序顺序中位于 `strB` 之后。

示例

以下示例调用 Compare(String, String) 方法以比较三组字符串。

using namespace System;

void main()
{
   // Create upper-case characters from their Unicode code units.
   String^ stringUpper = "\x0041\x0042\x0043";

   // Create lower-case characters from their Unicode code units.
   String^ stringLower = "\x0061\x0062\x0063";

   // Display the strings.
   Console::WriteLine("Comparing '{0}' and '{1}':", 
                      stringUpper, stringLower);

   // Compare the uppercased strings; the result is true.
   Console::WriteLine("The Strings are equal when capitalized? {0}",
                      String::Compare(stringUpper->ToUpper(), stringLower->ToUpper()) == 0 
                                      ? "true" : "false");

   // The previous method call is equivalent to this Compare method, which ignores case.
   Console::WriteLine("The Strings are equal when case is ignored? {0}",
                      String::Compare(stringUpper, stringLower, true) == 0
                                      ? "true" : "false");
}
// The example displays the following output:
//       Comparing 'ABC' and 'abc':
//       The Strings are equal when capitalized? true
//       The Strings are equal when case is ignored? true

// Create upper-case characters from their Unicode code units.
String stringUpper = "\x0041\x0042\x0043";

// Create lower-case characters from their Unicode code units.
String stringLower = "\x0061\x0062\x0063";

// Display the strings.
Console.WriteLine("Comparing '{0}' and '{1}':", 
                stringUpper, stringLower);

// Compare the uppercased strings; the result is true.
Console.WriteLine("The Strings are equal when capitalized? {0}",
                String.Compare(stringUpper.ToUpper(), stringLower.ToUpper()) == 0 
                               ? "true" : "false");

// The previous method call is equivalent to this Compare method, which ignores case.
Console.WriteLine("The Strings are equal when case is ignored? {0}",
                String.Compare(stringUpper, stringLower, true) == 0
                               ? "true" : "false" );

// The example displays the following output:
//       Comparing 'ABC' and 'abc':
//       The Strings are equal when capitalized? true
//       The Strings are equal when case is ignored? true

open System

// Create upper-case characters from their Unicode code units.
let stringUpper = "\x0041\x0042\x0043"

// Create lower-case characters from their Unicode code units.
let stringLower = "\x0061\x0062\x0063"

// Display the strings.
printfn $"Comparing '{stringUpper}' and '{stringLower}':"

// Compare the uppercased strings the result is true.
printfn $"The Strings are equal when capitalized? %b{String.Compare(stringUpper.ToUpper(), stringLower.ToUpper()) = 0}"

// The previous method call is equivalent to this Compare method, which ignores case.
printfn $"The Strings are equal when case is ignored? %b{String.Compare(stringUpper, stringLower, true) = 0}"

// The example displays the following output:
//       Comparing 'ABC' and 'abc':
//       The Strings are equal when capitalized? true
//       The Strings are equal when case is ignored? true

Public Module Example
   Public Sub Main()
      ' Create upper-case characters from their Unicode code units.
      Dim stringUpper As String = ChrW(&H41) + ChrW(&H42) + ChrW(&H43)

      ' Create lower-case characters from their Unicode code units.
      Dim stringLower As String = ChrW(&H61) + ChrW(&H62) + ChrW(&H63)

      ' Display the strings.
      Console.WriteLine("Comparing '{0}' and '{1}':", 
                        stringUpper, stringLower)

      ' Compare the uppercased strings; the result is true.
      Console.WriteLine("The Strings are equal when capitalized? {0}",
                        If(String.Compare(stringUpper.ToUpper(), stringLower.ToUpper()) = 0, 
                                          "true", "false"))

      ' The previous method call is equivalent to this Compare method, which ignores case.
      Console.WriteLine("The Strings are equal when case is ignored? {0}",
                        If(String.Compare(stringUpper, stringLower, true) = 0,
                                          "true", "false"))
   End Sub
End Module 
' The example displays the following output:
'       Comparing 'ABC' and 'abc':
'       The Strings are equal when capitalized? true
'       The Strings are equal when case is ignored? true

在下面的示例中， ReverseStringComparer 类演示如何使用 Compare 方法计算两个字符串。

using namespace System;
using namespace System::Text;
using namespace System::Collections;

ref class ReverseStringComparer: public IComparer
{
public:
   virtual int Compare( Object^ x, Object^ y )
   {
      String^ s1 = dynamic_cast<String^>(x);
      String^ s2 = dynamic_cast<String^>(y);

      //negate the return value to get the reverse order
      return  -String::Compare( s1, s2 );
   }

};

void PrintValues( String^ title, IEnumerable^ myList )
{
   Console::Write( "{0,10}: ", title );
   StringBuilder^ sb = gcnew StringBuilder;
   {
      IEnumerator^ en = myList->GetEnumerator();
      String^ s;
      while ( en->MoveNext() )
      {
         s = en->Current->ToString();
         sb->AppendFormat(  "{0}, ", s );
      }
   }
   sb->Remove( sb->Length - 2, 2 );
   Console::WriteLine( sb );
}

void main()
{
   // Creates and initializes a new ArrayList.
   ArrayList^ myAL = gcnew ArrayList;
   myAL->Add( "Eric" );
   myAL->Add( "Mark" );
   myAL->Add( "Lance" );
   myAL->Add( "Rob" );
   myAL->Add( "Kris" );
   myAL->Add( "Brad" );
   myAL->Add( "Kit" );
   myAL->Add( "Bradley" );
   myAL->Add( "Keith" );
   myAL->Add( "Susan" );

   // Displays the properties and values of the ArrayList.
   Console::WriteLine( "Count: {0}", myAL->Count.ToString() );

   PrintValues( "Unsorted", myAL );

   myAL->Sort();
   PrintValues( "Sorted", myAL );

   myAL->Sort( gcnew ReverseStringComparer );
   PrintValues( "Reverse", myAL );

   array<String^>^names = dynamic_cast<array<String^>^>(myAL->ToArray( String::typeid ));
}

using System;
using System.Text;
using System.Collections;

public class SamplesArrayList
{

    public static void Main()
    {
        // Creates and initializes a new ArrayList.
        ArrayList myAL = new ArrayList();
        myAL.Add("Eric");
        myAL.Add("Mark");
        myAL.Add("Lance");
        myAL.Add("Rob");
        myAL.Add("Kris");
        myAL.Add("Brad");
        myAL.Add("Kit");
        myAL.Add("Bradley");
        myAL.Add("Keith");
        myAL.Add("Susan");

        // Displays the properties and values of	the	ArrayList.
        Console.WriteLine("Count: {0}", myAL.Count);

        PrintValues("Unsorted", myAL);
        myAL.Sort();
        PrintValues("Sorted", myAL);
        myAL.Sort(new ReverseStringComparer());
        PrintValues("Reverse", myAL);

        string[] names = (string[])myAL.ToArray(typeof(string));
    }
    public static void PrintValues(string title, IEnumerable myList)
    {
        Console.Write("{0,10}: ", title);
        StringBuilder sb = new StringBuilder();
        foreach (string s in myList)
        {
            sb.AppendFormat("{0}, ", s);
        }
        sb.Remove(sb.Length - 2, 2);
        Console.WriteLine(sb);
    }
}
public class ReverseStringComparer : IComparer
{
    public int Compare(object? x, object? y)
    {
        string? s1 = x as string;
        string? s2 = y as string;
        //negate the return value to get the reverse order
        return -String.Compare(s1, s2);
    }
}

open System
open System.Text
open System.Collections.Generic

type ReverseStringComparer() =
    interface IComparer<string> with
        member _.Compare(x, y) =
            -String.Compare(x, y)

let printValues title (myList: #seq<string>) =
    printf $"{title,10}: "
    let sb = StringBuilder()
    for s in myList do
        sb.Append $"{s}, " |> ignore
    sb.Remove(sb.Length - 2, 2) |> ignore
    printfn $"{sb}"

// Creates and initializes a new ResizeArray.
let myAL = ResizeArray()
myAL.Add "Eric"
myAL.Add "Mark"
myAL.Add "Lance"
myAL.Add "Rob"
myAL.Add "Kris"
myAL.Add "Brad"
myAL.Add "Kit"
myAL.Add "Bradley"
myAL.Add "Keith"
myAL.Add "Susan"

// Displays the properties and values of	the	ArrayList.
printfn $"Count: {myAL.Count}"

printValues "Unsorted" myAL
myAL.Sort()
printValues "Sorted" myAL
myAL.Sort(ReverseStringComparer())
printValues "Reverse" myAL

Imports System.Text
Imports System.Collections



Public Class SamplesArrayList
    
    
    Public Shared Sub Main()
        Dim myAL As New ArrayList()
        ' Creates and initializes a new ArrayList.
        myAL.Add("Eric")
        myAL.Add("Mark")
        myAL.Add("Lance")
        myAL.Add("Rob")
        myAL.Add("Kris")
        myAL.Add("Brad")
        myAL.Add("Kit")
        myAL.Add("Bradley")
        myAL.Add("Keith")
        myAL.Add("Susan")
        
        ' Displays the properties and values of	the	ArrayList.
        Console.WriteLine("Count: {0}", myAL.Count)
        PrintValues("Unsorted", myAL)
        myAL.Sort()
        PrintValues("Sorted", myAL)
        Dim comp as New ReverseStringComparer
        myAL.Sort(comp)
        PrintValues("Reverse", myAL)

        Dim names As String() = CType(myAL.ToArray(GetType(String)), String())
    End Sub
   
   
    
    Public Shared Sub PrintValues(title As String, myList As IEnumerable)
        Console.Write("{0,10}: ", title)
        Dim sb As New StringBuilder()
        Dim s As String
        For Each s In  myList
            sb.AppendFormat("{0}, ", s)
        Next s
        sb.Remove(sb.Length - 2, 2)
        Console.WriteLine(sb)
    End Sub
End Class

Public Class ReverseStringComparer 
  Implements IComparer
    
     Function Compare(x As Object, y As Object) As Integer implements IComparer.Compare
        Dim s1 As String = CStr (x)
        Dim s2 As String = CStr (y)
        
        'negate the return value to get the reverse order
        Return - [String].Compare(s1, s2)
    
    End Function 'Compare
End Class

注解

比较是使用单词排序规则执行的。有关单词、字符串和序号排序的详细信息，请参阅 System.Globalization.CompareOptions。

警告

比较字符串时，应调用 Compare(String, String, StringComparison) 方法，这要求显式指定该方法使用的字符串比较类型。有关详细信息，请参阅有关使用字符串的最佳实践。

一个或两个比较可以是 null。根据定义，任何字符串（包括空字符串 (“”) ）都比较大于 null 引用;和两个 null 引用相等比较。

当发现不相等或两个字符串都已比较时，比较终止。但是，如果两个字符串的比较等于一个字符串的末尾，而另一个字符串的剩余字符，则认为具有剩余字符的字符串更大。返回值是上次执行的比较的结果。

static bool IsFileURI(String^ path)
{
    return (String::Compare(path, 0, "file:", 0, 5, true) == 0);
}

static bool IsFileURI(String path)
{
    return (String.Compare(path, 0, "file:", 0, 5, true) == 0);
}

let isFileURI path =
    String.Compare(path, 0, "file:", 0, 5, true) = 0

Shared Function IsFileURI(ByVal path As String) As Boolean
    If String.Compare(path, 0, "file:", 0, 5, True) = 0 Then
        Return True
    Else
        Return False
    End If
End Function

使用序号比较将路径名与“文件”进行比较。执行此操作的正确代码如下所示：

static bool IsFileURI(String^ path)
{
    return (String::Compare(path, 0, "file:", 0, 5, StringComparison::OrdinalIgnoreCase) == 0);
}

static bool IsFileURI(String path)
{
    return (String.Compare(path, 0, "file:", 0, 5, StringComparison.OrdinalIgnoreCase) == 0);
}

let isFileURI path =
    String.Compare(path, 0, "file:", 0, 5, StringComparison.OrdinalIgnoreCase) = 0

Shared Function IsFileURI(ByVal path As String) As Boolean
    If String.Compare(path, 0, "file:", 0, 5, StringComparison.OrdinalIgnoreCase) = 0 Then
        Return True
    Else
        Return False
    End If
End Function

调用方说明

字符集包括可忽略字符。方法 Compare(String, String) 在执行区分区域性的比较时不考虑此类字符。例如，如果在 .NET Framework 4 或更高版本上运行以下代码，则使用软连字符或 U+00AD (对“animal”与“ani-mal”进行区域性敏感比较，或 U+00AD) 指示这两个字符串是等效的。

string s1 = "ani\u00ADmal";
string s2 = "animal";

Console.WriteLine("Comparison of '{0}' and '{1}': {2}",
                s1, s2, String.Compare(s1, s2));

// The example displays the following output:
//       Comparison of 'ani-mal' and 'animal': 0

open System

let s1 = "ani\u00ADmal"
let s2 = "animal"

printfn $"Comparison of '{s1}' and '{s2}': {String.Compare(s1, s2)}"

// The example displays the following output:
//       Comparison of 'ani-mal' and 'animal': 0

Module Example
   Public Sub Main()
      Dim s1 As String = "ani" + ChrW(&h00AD) + "mal"
      Dim s2 As String = "animal"
      
      Console.WriteLine("Comparison of '{0}' and '{1}': {2}", 
                        s1, s2, String.Compare(s1, s2))
  End Sub
End Module
' The example displays the following output:
'       Comparison of 'ani-mal' and 'animal': 0

若要识别字符串比较中的可忽略字符，请调用 Compare(String, String, StringComparison) 方法并为参数提供或 OrdinalIgnoreCasecomparisonType 值Ordinal。

另请参阅

适用于

Compare(String, String, Boolean, CultureInfo)

比较两个指定的 String 对象（其中忽略或考虑其大小写，并使用区域性特定的信息干预比较），并返回一个整数，指示二者在排序顺序中的相对位置。

public:
 static int Compare(System::String ^ strA, System::String ^ strB, bool ignoreCase, System::Globalization::CultureInfo ^ culture);

public static int Compare (string? strA, string? strB, bool ignoreCase, System.Globalization.CultureInfo? culture);

public static int Compare (string strA, string strB, bool ignoreCase, System.Globalization.CultureInfo culture);

static member Compare : string * string * bool * System.Globalization.CultureInfo -> int

Public Shared Function Compare (strA As String, strB As String, ignoreCase As Boolean, culture As CultureInfo) As Integer

参数

strA: String

要比较的第一个字符串。

strB: String

要比较的第二个字符串。

ignoreCase: Boolean

若要在比较过程中忽略大小写，则为 true；否则为 false。

culture: CultureInfo

一个对象，提供区域性特定的比较信息。如果 culture 为 null，则使用当前区域性。

Int32

一个 32 位带符号整数，指示两个比较数之间的词法关系。

“值”	条件
小于零	`strA` 在排序顺序中位于 `strB` 之前。
零	`strA` 与 `strB` 在排序顺序中出现的位置相同。
大于零	`strA` 在排序顺序中位于 `strB` 之后。

示例

以下示例演示区域性如何影响比较。在捷克共和国文化中，“ch”是大于“d”的单个字符。但是，在英语美国区域性中，“ch”由两个字符组成，而“c”小于“d”。

using namespace System;
using namespace System::Globalization;
String^ symbol( int r )
{
   String^ s = "=";
   if ( r < 0 )
      s = "<";
   else
   if ( r > 0 )
      s = ">";


   return s;
}

int main()
{
   String^ str1 = "change";
   String^ str2 = "dollar";
   String^ relation = nullptr;
   relation = symbol( String::Compare( str1, str2, false, gcnew CultureInfo( "en-US" ) ) );
   Console::WriteLine( "For en-US: {0} {1} {2}", str1, relation, str2 );
   relation = symbol( String::Compare( str1, str2, false, gcnew CultureInfo( "cs-CZ" ) ) );
   Console::WriteLine( "For cs-CZ: {0} {1} {2}", str1, relation, str2 );
}

/*
This example produces the following results.
For en-US: change < dollar
For cs-CZ: change > dollar
*/

public static void Main()
{
    String str1 = "change";
    String str2 = "dollar";
    String relation;

    relation = symbol(String.Compare(str1, str2, false, new CultureInfo("en-US")));
    Console.WriteLine("For en-US: {0} {1} {2}", str1, relation, str2);

    relation = symbol(String.Compare(str1, str2, false, new CultureInfo("cs-CZ")));
    Console.WriteLine("For cs-CZ: {0} {1} {2}", str1, relation, str2);
}

private static String symbol(int r)
{
    String s = "=";
    if (r < 0) s = "<";
    else if (r > 0) s = ">";
    return s;
}

/*
This example produces the following results.
For en-US: change < dollar
For cs-CZ: change > dollar
*/

let symbol r =
    if r < 0 then "<"
    elif r > 0 then ">"
    else "="

let str1 = "change"
let str2 = "dollar"

let relation1 = 
    String.Compare(str1, str2, false, CultureInfo "en-US")
    |> symbol
printfn $"For en-US: {str1} {relation1} {str2}"

let relation2 = 
    String.Compare(str1, str2, false, CultureInfo "cs-CZ")
    |> symbol
printfn $"For cs-CZ: {str1} {relation2} {str2}"

(*
This example produces the following results.
For en-US: change < dollar
For cs-CZ: change > dollar
*)

Imports System.Globalization
 _

Class Sample
   Public Shared Sub Main()
      Dim str1 As [String] = "change"
      Dim str2 As [String] = "dollar"
      Dim relation As [String] = Nothing
      
      relation = symbol([String].Compare(str1, str2, False, New CultureInfo("en-US")))
      Console.WriteLine("For en-US: {0} {1} {2}", str1, relation, str2)
      
      relation = symbol([String].Compare(str1, str2, False, New CultureInfo("cs-CZ")))
      Console.WriteLine("For cs-CZ: {0} {1} {2}", str1, relation, str2)
   End Sub
   
   Private Shared Function symbol(r As Integer) As [String]
      Dim s As [String] = "="
      If r < 0 Then
         s = "<"
      Else
         If r > 0 Then
            s = ">"
         End If
      End If
      Return s
   End Function 'symbol
End Class
'
'This example produces the following results.
'For en-US: change < dollar
'For cs-CZ: change > dollar
'

注解

比较使用 culture 参数获取特定于区域性的信息，例如大小写规则和单个字符的字母顺序。例如，区域性可以指定将字符的某些组合视为单个字符，或者以特定方式比较大写和小写字符，或者字符的排序顺序取决于其前面或后面的字符。

比较是使用单词排序规则执行的。有关单词、字符串和序号排序的详细信息，请参阅 System.Globalization.CompareOptions。

一个或两个比较可以是 null。根据定义，任何字符串（包括空字符串 (“”) ）都比较大于 null 引用;和两个 null 引用相等比较。

static bool IsFileURI(String^ path)
{
    return (String::Compare(path, 0, "file:", 0, 5, true) == 0);
}

static bool IsFileURI(String path)
{
    return (String.Compare(path, 0, "file:", 0, 5, true) == 0);
}

let isFileURI path =
    String.Compare(path, 0, "file:", 0, 5, true) = 0

Shared Function IsFileURI(ByVal path As String) As Boolean
    If String.Compare(path, 0, "file:", 0, 5, True) = 0 Then
        Return True
    Else
        Return False
    End If
End Function

使用序号比较将路径名与“文件”进行比较。执行此操作的正确代码如下所示：

static bool IsFileURI(String^ path)
{
    return (String::Compare(path, 0, "file:", 0, 5, StringComparison::OrdinalIgnoreCase) == 0);
}

static bool IsFileURI(String path)
{
    return (String.Compare(path, 0, "file:", 0, 5, StringComparison.OrdinalIgnoreCase) == 0);
}

let isFileURI path =
    String.Compare(path, 0, "file:", 0, 5, StringComparison.OrdinalIgnoreCase) = 0

Shared Function IsFileURI(ByVal path As String) As Boolean
    If String.Compare(path, 0, "file:", 0, 5, StringComparison.OrdinalIgnoreCase) = 0 Then
        Return True
    Else
        Return False
    End If
End Function

调用方说明

字符集包括可忽略字符。方法 Compare(String, String, Boolean, CultureInfo) 在执行区分区域性的比较时不考虑此类字符。例如，如果以下代码在 .NET Framework 4 或更高版本上运行，则使用软连字符将“animal”与“Ani-mal” (不区分大小写的比较，或使用固定区域性的 U+00AD) 表示这两个字符串是等效的。

  string s1 = "Ani\u00ADmal";
  string s2 = "animal";

  Console.WriteLine("Comparison of '{0}' and '{1}': {2}", 
                  s1, s2, String.Compare(s1, s2, true,
                  CultureInfo.InvariantCulture));

  // The example displays the following output:
  //       Comparison of 'Ani-mal' and 'animal': 0

open System
open System.Globalization

let s1 = "Ani\u00ADmal"
let s2 = "animal"

printfn $"Comparison of '{s1}' and '{s2}': {String.Compare(s1, s2, true, CultureInfo.InvariantCulture)}"

// The example displays the following output:
//       Comparison of 'Ani-mal' and 'animal': 0

Imports System.Globalization

Module Example
   Public Sub Main()
      Dim s1 As String = "Ani" + ChrW(&h00AD) + "mal"
      Dim s2 As String = "animal"
      
      Console.WriteLine("Comparison of '{0}' and '{1}': {2}", 
                        s1, s2, String.Compare(s1, s2, True,
                        CultureInfo.InvariantCulture))
  End Sub
End Module
' The example displays the following output:
'       Comparison of 'ani-mal' and 'animal': 0

若要识别字符串比较中的可忽略字符，请调用 Compare(String, String, CultureInfo, CompareOptions) 方法并为参数提供或 OrdinalIgnoreCaseoptions 值Ordinal。

另请参阅

适用于

Compare(String, String, StringComparison)

使用指定的规则比较两个指定的 String 对象，并返回一个整数，指示二者在排序顺序中的相对位置。

public:
 static int Compare(System::String ^ strA, System::String ^ strB, StringComparison comparisonType);

public static int Compare (string strA, string strB, StringComparison comparisonType);

public static int Compare (string? strA, string? strB, StringComparison comparisonType);

static member Compare : string * string * StringComparison -> int

Public Shared Function Compare (strA As String, strB As String, comparisonType As StringComparison) As Integer

参数

strA: String

要比较的第一个字符串。

strB: String

要比较的第二个字符串。

comparisonType: StringComparison

一个枚举值，用于指定比较中要使用的规则。

Int32

一个 32 位带符号整数，指示两个比较数之间的词法关系。

“值”	条件
小于零	`strA` 在排序顺序中位于 `strB` 之前。
零	`strA` 与 `strB` 在排序顺序中的位置相同。
大于零	`strA` 在排序顺序中位于 `strB` 之后。

例外

ArgumentException

comparisonType 不是 StringComparison 值。

NotSupportedException

不支持 StringComparison。

示例

以下示例比较字母“I”的三个版本。结果受区域性选择、是否忽略大小写以及是否执行序号比较的影响。

// This example demonstrates the
// System.String.Compare(String, String, StringComparison) method.

using namespace System;
using namespace System::Threading;

void Test(int testStringIndex, int searchStringIndex, 
          StringComparison comparison, array<String^>^ testI, 
          array<String^>^ testNames)
{
    String^ resultFormat = "{0} is {1} {2}";
    String^ resultString = "equal to";
    int comparisonValue = 0;

    comparisonValue = String::Compare(testI[testStringIndex],
        testI[searchStringIndex], comparison);
    if (comparisonValue < 0)
    {
        resultString = "less than";
    }
    else if (comparisonValue > 0)
    {
        resultString = "greater than";
    }
    Console::WriteLine(resultFormat, testNames[testStringIndex], resultString,
        testNames[searchStringIndex]);
}

int main()
{
    String^ introMessage =
        "Compare three versions of the letter I using different " +
        "values of StringComparison.";

    // Define an array of strings where each element contains a version of
    // the letter I. (An array of strings is used so you can easily modify
    // this code example to test additional or different combinations of
    // strings.)

    array<String^>^ letterVariation = gcnew array<String^>(3);
    // LATIN SMALL LETTER I (U+0069)
    letterVariation[0] = "i";
    // LATIN SMALL LETTER DOTLESS I (U+0131)
    letterVariation[1] = L"\u0131";
    // LATIN CAPITAL LETTER I (U+0049)
    letterVariation[2] = "I";

    array<String^>^ unicodeNames = {
        "LATIN SMALL LETTER I (U+0069)",
        "LATIN SMALL LETTER DOTLESS I (U+0131)",
        "LATIN CAPITAL LETTER I (U+0049)"};

    array<StringComparison>^ comparisonValues = {
        StringComparison::CurrentCulture,
        StringComparison::CurrentCultureIgnoreCase,
        StringComparison::InvariantCulture,
        StringComparison::InvariantCultureIgnoreCase,
        StringComparison::Ordinal,
        StringComparison::OrdinalIgnoreCase};

    Console::Clear();
    Console::WriteLine(introMessage);

    // Display the current culture because the culture-specific comparisons
    // can produce different results with different cultures.
    Console::WriteLine("The current culture is {0}.{1}",
        Thread::CurrentThread->CurrentCulture->Name, Environment::NewLine);

    // Determine the relative sort order of three versions of the letter I.
    for each (StringComparison stringCmp in comparisonValues)
    {
        Console::WriteLine("StringComparison.{0}:", stringCmp);

        // LATIN SMALL LETTER I (U+0069) : LATIN SMALL LETTER DOTLESS I
        // (U+0131)
        Test(0, 1, stringCmp, letterVariation, unicodeNames);

        // LATIN SMALL LETTER I (U+0069) : LATIN CAPITAL LETTER I (U+0049)
        Test(0, 2, stringCmp, letterVariation, unicodeNames);

        // LATIN SMALL LETTER DOTLESS I (U+0131) : LATIN CAPITAL LETTER I
        // (U+0049)
        Test(1, 2, stringCmp, letterVariation, unicodeNames);

        Console::WriteLine();
    }
}

/*
This code example produces the following results:

Compare three versions of the letter I using different values of 
StringComparison.
The current culture is en-US.

StringComparison.CurrentCulture:
LATIN SMALL LETTER I (U+0069) is less than LATIN SMALL LETTER 
  DOTLESS I (U+0131)
LATIN SMALL LETTER I (U+0069) is less than LATIN CAPITAL LETTER I (U+0049)
LATIN SMALL LETTER DOTLESS I (U+0131) is greater than LATIN 
  CAPITAL LETTER I (U+0049)

StringComparison.CurrentCultureIgnoreCase:
LATIN SMALL LETTER I (U+0069) is less than LATIN SMALL LETTER 
  DOTLESS I (U+0131)
LATIN SMALL LETTER I (U+0069) is equal to LATIN CAPITAL LETTER I (U+0049)
LATIN SMALL LETTER DOTLESS I (U+0131) is greater than LATIN 
  CAPITAL LETTER I (U+0049)

StringComparison.InvariantCulture:
LATIN SMALL LETTER I (U+0069) is less than LATIN SMALL LETTER 
  DOTLESS I (U+0131)
LATIN SMALL LETTER I (U+0069) is less than LATIN CAPITAL LETTER I (U+0049)
LATIN SMALL LETTER DOTLESS I (U+0131) is greater than LATIN 
  CAPITAL LETTER I (U+0049)

StringComparison.InvariantCultureIgnoreCase:
LATIN SMALL LETTER I (U+0069) is less than LATIN SMALL LETTER 
  DOTLESS I (U+0131)
LATIN SMALL LETTER I (U+0069) is equal to LATIN CAPITAL LETTER I (U+0049)
LATIN SMALL LETTER DOTLESS I (U+0131) is greater than LATIN 
  CAPITAL LETTER I (U+0049)

StringComparison.Ordinal:
LATIN SMALL LETTER I (U+0069) is less than LATIN SMALL LETTER 
  DOTLESS I (U+0131)
LATIN SMALL LETTER I (U+0069) is greater than LATIN CAPITAL LETTER I (U+0049)
LATIN SMALL LETTER DOTLESS I (U+0131) is greater than LATIN 
  CAPITAL LETTER I (U+0049)

StringComparison.OrdinalIgnoreCase:
LATIN SMALL LETTER I (U+0069) is less than LATIN SMALL LETTER 
  DOTLESS I (U+0131)
LATIN SMALL LETTER I (U+0069) is equal to LATIN CAPITAL LETTER I (U+0049)
LATIN SMALL LETTER DOTLESS I (U+0131) is greater than LATIN 
  CAPITAL LETTER I (U+0049)

*/

// This example demonstrates the 
// System.String.Compare(String, String, StringComparison) method.

using System;
using System.Threading;

class Sample 
{
    public static void Main() 
    {
        string intro = "Compare three versions of the letter I using different " + 
                       "values of StringComparison.";

        // Define an array of strings where each element contains a version of the 
        // letter I. (An array of strings is used so you can easily modify this 
        // code example to test additional or different combinations of strings.)  

        string[] threeIs = new string[3];
        // LATIN SMALL LETTER I (U+0069)
        threeIs[0] = "\u0069";
        // LATIN SMALL LETTER DOTLESS I (U+0131)
        threeIs[1] = "\u0131";
        // LATIN CAPITAL LETTER I (U+0049)
        threeIs[2] = "\u0049";

        string[] unicodeNames = 
        {
            "LATIN SMALL LETTER I (U+0069)", 
            "LATIN SMALL LETTER DOTLESS I (U+0131)", 
            "LATIN CAPITAL LETTER I (U+0049)"
        };

        StringComparison[] scValues =
        {
            StringComparison.CurrentCulture,
            StringComparison.CurrentCultureIgnoreCase,
            StringComparison.InvariantCulture,
            StringComparison.InvariantCultureIgnoreCase,
            StringComparison.Ordinal,
            StringComparison.OrdinalIgnoreCase
        };

        Console.Clear();
        Console.WriteLine(intro);

        // Display the current culture because the culture-specific comparisons
        // can produce different results with different cultures.
        Console.WriteLine(
            "The current culture is {0}.\n", Thread.CurrentThread.CurrentCulture.Name);

        // Determine the relative sort order of three versions of the letter I. 
        foreach (StringComparison sc in scValues)
        {
            Console.WriteLine("StringComparison.{0}:", sc);

            // LATIN SMALL LETTER I (U+0069) : LATIN SMALL LETTER DOTLESS I (U+0131)
            Test(0, 1, sc, threeIs, unicodeNames);

            // LATIN SMALL LETTER I (U+0069) : LATIN CAPITAL LETTER I (U+0049)
            Test(0, 2, sc, threeIs, unicodeNames);

            // LATIN SMALL LETTER DOTLESS I (U+0131) : LATIN CAPITAL LETTER I (U+0049)
            Test(1, 2, sc, threeIs, unicodeNames);

            Console.WriteLine();
        }
    }

    protected static void Test(
        int x, int y, StringComparison comparison, string[] testI, string[] testNames)
    {
        string resultFmt = "{0} is {1} {2}";
        string result = "equal to";
        int cmpValue = 0;

        cmpValue = String.Compare(testI[x], testI[y], comparison);
        if (cmpValue < 0)
            result = "less than";
        else if (cmpValue > 0)
            result = "greater than";
        Console.WriteLine(resultFmt, testNames[x], result, testNames[y]);
    }
}

/*
This code example produces the following results:

Compare three versions of the letter I using different values of StringComparison.
The current culture is en-US.

StringComparison.CurrentCulture:
LATIN SMALL LETTER I (U+0069) is less than LATIN SMALL LETTER DOTLESS I (U+0131)
LATIN SMALL LETTER I (U+0069) is less than LATIN CAPITAL LETTER I (U+0049)
LATIN SMALL LETTER DOTLESS I (U+0131) is greater than LATIN CAPITAL LETTER I (U+0049)

StringComparison.CurrentCultureIgnoreCase:
LATIN SMALL LETTER I (U+0069) is less than LATIN SMALL LETTER DOTLESS I (U+0131)
LATIN SMALL LETTER I (U+0069) is equal to LATIN CAPITAL LETTER I (U+0049)
LATIN SMALL LETTER DOTLESS I (U+0131) is greater than LATIN CAPITAL LETTER I (U+0049)

StringComparison.InvariantCulture:
LATIN SMALL LETTER I (U+0069) is less than LATIN SMALL LETTER DOTLESS I (U+0131)
LATIN SMALL LETTER I (U+0069) is less than LATIN CAPITAL LETTER I (U+0049)
LATIN SMALL LETTER DOTLESS I (U+0131) is greater than LATIN CAPITAL LETTER I (U+0049)

StringComparison.InvariantCultureIgnoreCase:
LATIN SMALL LETTER I (U+0069) is less than LATIN SMALL LETTER DOTLESS I (U+0131)
LATIN SMALL LETTER I (U+0069) is equal to LATIN CAPITAL LETTER I (U+0049)
LATIN SMALL LETTER DOTLESS I (U+0131) is greater than LATIN CAPITAL LETTER I (U+0049)

StringComparison.Ordinal:
LATIN SMALL LETTER I (U+0069) is less than LATIN SMALL LETTER DOTLESS I (U+0131)
LATIN SMALL LETTER I (U+0069) is greater than LATIN CAPITAL LETTER I (U+0049)
LATIN SMALL LETTER DOTLESS I (U+0131) is greater than LATIN CAPITAL LETTER I (U+0049)

StringComparison.OrdinalIgnoreCase:
LATIN SMALL LETTER I (U+0069) is less than LATIN SMALL LETTER DOTLESS I (U+0131)
LATIN SMALL LETTER I (U+0069) is equal to LATIN CAPITAL LETTER I (U+0049)
LATIN SMALL LETTER DOTLESS I (U+0131) is greater than LATIN CAPITAL LETTER I (U+0049)

*/

// This example demonstrates the 
// System.String.Compare(String, String, StringComparison) method.

open System
open System.Threading

let test x y (comparison: StringComparison) (testI: string[]) (testNames: string[]) =
    let cmpValue = String.Compare(testI[x], testI[y], comparison)
    let result =
        if cmpValue < 0 then
            "less than"
        elif cmpValue > 0 then
            "greater than"
        else
            "equal to"
    printfn $"{testNames[x]} is {result} {testNames[y]}"

let intro = "Compare three versions of the letter I using different values of StringComparison."

// Define an array of strings where each element contains a version of the 
// letter I. (An array of strings is used so you can easily modify this 
// code example to test additional or different combinations of strings.)  

let threeIs = 
  [|// LATIN SMALL LETTER I (U+0069)
    "\u0069"
    // LATIN SMALL LETTER DOTLESS I (U+0131)
    "\u0131"
    // LATIN CAPITAL LETTER I (U+0049)
    "\u0049" |]

let unicodeNames =
    [| "LATIN SMALL LETTER I (U+0069)"
       "LATIN SMALL LETTER DOTLESS I (U+0131)"
       "LATIN CAPITAL LETTER I (U+0049)" |]

let scValues =
    [| StringComparison.CurrentCulture
       StringComparison.CurrentCultureIgnoreCase
       StringComparison.InvariantCulture
       StringComparison.InvariantCultureIgnoreCase
       StringComparison.Ordinal
       StringComparison.OrdinalIgnoreCase |]

Console.Clear()
printfn $"{intro}"

// Display the current culture because the culture-specific comparisons
// can produce different results with different cultures.
printfn $"The current culture is {Thread.CurrentThread.CurrentCulture.Name}.\n"

// Determine the relative sort order of three versions of the letter I. 
for sc in scValues do
    printfn $"StringComparison.{sc}:"

    // LATIN SMALL LETTER I (U+0069) : LATIN SMALL LETTER DOTLESS I (U+0131)
    test 0 1 sc threeIs unicodeNames

    // LATIN SMALL LETTER I (U+0069) : LATIN CAPITAL LETTER I (U+0049)
    test 0 2 sc threeIs unicodeNames

    // LATIN SMALL LETTER DOTLESS I (U+0131) : LATIN CAPITAL LETTER I (U+0049)
    test 1 2 sc threeIs unicodeNames

    printfn ""

(*
This code example produces the following results:

Compare three versions of the letter I using different values of StringComparison.
The current culture is en-US.

StringComparison.CurrentCulture:
LATIN SMALL LETTER I (U+0069) is less than LATIN SMALL LETTER DOTLESS I (U+0131)
LATIN SMALL LETTER I (U+0069) is less than LATIN CAPITAL LETTER I (U+0049)
LATIN SMALL LETTER DOTLESS I (U+0131) is greater than LATIN CAPITAL LETTER I (U+0049)

StringComparison.CurrentCultureIgnoreCase:
LATIN SMALL LETTER I (U+0069) is less than LATIN SMALL LETTER DOTLESS I (U+0131)
LATIN SMALL LETTER I (U+0069) is equal to LATIN CAPITAL LETTER I (U+0049)
LATIN SMALL LETTER DOTLESS I (U+0131) is greater than LATIN CAPITAL LETTER I (U+0049)

StringComparison.InvariantCulture:
LATIN SMALL LETTER I (U+0069) is less than LATIN SMALL LETTER DOTLESS I (U+0131)
LATIN SMALL LETTER I (U+0069) is less than LATIN CAPITAL LETTER I (U+0049)
LATIN SMALL LETTER DOTLESS I (U+0131) is greater than LATIN CAPITAL LETTER I (U+0049)

StringComparison.InvariantCultureIgnoreCase:
LATIN SMALL LETTER I (U+0069) is less than LATIN SMALL LETTER DOTLESS I (U+0131)
LATIN SMALL LETTER I (U+0069) is equal to LATIN CAPITAL LETTER I (U+0049)
LATIN SMALL LETTER DOTLESS I (U+0131) is greater than LATIN CAPITAL LETTER I (U+0049)

StringComparison.Ordinal:
LATIN SMALL LETTER I (U+0069) is less than LATIN SMALL LETTER DOTLESS I (U+0131)
LATIN SMALL LETTER I (U+0069) is greater than LATIN CAPITAL LETTER I (U+0049)
LATIN SMALL LETTER DOTLESS I (U+0131) is greater than LATIN CAPITAL LETTER I (U+0049)

StringComparison.OrdinalIgnoreCase:
LATIN SMALL LETTER I (U+0069) is less than LATIN SMALL LETTER DOTLESS I (U+0131)
LATIN SMALL LETTER I (U+0069) is equal to LATIN CAPITAL LETTER I (U+0049)
LATIN SMALL LETTER DOTLESS I (U+0131) is greater than LATIN CAPITAL LETTER I (U+0049)
*)

' This example demonstrates the 
' System.String.Compare(String, String, StringComparison) method.

Imports System.Threading

Class Sample
    Public Shared Sub Main() 
        Dim intro As String = "Compare three versions of the letter I using different " & _
                              "values of StringComparison."
        
        ' Define an array of strings where each element contains a version of the 
        ' letter I. (An array of strings is used so you can easily modify this 
        ' code example to test additional or different combinations of strings.)  
        Dim threeIs(2) As String
        ' LATIN SMALL LETTER I (U+0069)
        threeIs(0) = "i"
        ' LATIN SMALL LETTER DOTLESS I (U+0131)
        threeIs(1) = "ı"
        ' LATIN CAPITAL LETTER I (U+0049)
        threeIs(2) = "I"
        
        Dim unicodeNames As String() =  { _
                            "LATIN SMALL LETTER I (U+0069)", _
                            "LATIN SMALL LETTER DOTLESS I (U+0131)", _
                            "LATIN CAPITAL LETTER I (U+0049)" }
        
        Dim scValues As StringComparison() =  { _
                            StringComparison.CurrentCulture, _
                            StringComparison.CurrentCultureIgnoreCase, _
                            StringComparison.InvariantCulture, _
                            StringComparison.InvariantCultureIgnoreCase, _
                            StringComparison.Ordinal, _
                            StringComparison.OrdinalIgnoreCase }
        '
        Console.Clear()
        Console.WriteLine(intro)
        
        ' Display the current culture because the culture-specific comparisons
        ' can produce different results with different cultures.
        Console.WriteLine("The current culture is {0}." & vbCrLf, _
                           Thread.CurrentThread.CurrentCulture.Name)
        
        ' Determine the relative sort order of three versions of the letter I. 
        Dim sc As StringComparison
        For Each sc In  scValues
            Console.WriteLine("StringComparison.{0}:", sc)
            
            ' LATIN SMALL LETTER I (U+0069) : LATIN SMALL LETTER DOTLESS I (U+0131)
            Test(0, 1, sc, threeIs, unicodeNames)
            
            ' LATIN SMALL LETTER I (U+0069) : LATIN CAPITAL LETTER I (U+0049)
            Test(0, 2, sc, threeIs, unicodeNames)
            
            ' LATIN SMALL LETTER DOTLESS I (U+0131) : LATIN CAPITAL LETTER I (U+0049)
            Test(1, 2, sc, threeIs, unicodeNames)
            
            Console.WriteLine()
        Next sc
    
    End Sub
    
    Protected Shared Sub Test(ByVal x As Integer, ByVal y As Integer, _
                              ByVal comparison As StringComparison, _
                              ByVal testI() As String, ByVal testNames() As String) 
        Dim resultFmt As String = "{0} is {1} {2}"
        Dim result As String = "equal to"
        Dim cmpValue As Integer = 0
        '
        cmpValue = String.Compare(testI(x), testI(y), comparison)
        If cmpValue < 0 Then
            result = "less than"
        ElseIf cmpValue > 0 Then
            result = "greater than"
        End If
        Console.WriteLine(resultFmt, testNames(x), result, testNames(y))
    
    End Sub
End Class

'
'This code example produces the following results:
'
'Compare three versions of the letter I using different values of StringComparison.
'The current culture is en-US.
'
'StringComparison.CurrentCulture:
'LATIN SMALL LETTER I (U+0069) is less than LATIN SMALL LETTER DOTLESS I (U+0131)
'LATIN SMALL LETTER I (U+0069) is less than LATIN CAPITAL LETTER I (U+0049)
'LATIN SMALL LETTER DOTLESS I (U+0131) is greater than LATIN CAPITAL LETTER I (U+0049)
'
'StringComparison.CurrentCultureIgnoreCase:
'LATIN SMALL LETTER I (U+0069) is less than LATIN SMALL LETTER DOTLESS I (U+0131)
'LATIN SMALL LETTER I (U+0069) is equal to LATIN CAPITAL LETTER I (U+0049)
'LATIN SMALL LETTER DOTLESS I (U+0131) is greater than LATIN CAPITAL LETTER I (U+0049)
'
'StringComparison.InvariantCulture:
'LATIN SMALL LETTER I (U+0069) is less than LATIN SMALL LETTER DOTLESS I (U+0131)
'LATIN SMALL LETTER I (U+0069) is less than LATIN CAPITAL LETTER I (U+0049)
'LATIN SMALL LETTER DOTLESS I (U+0131) is greater than LATIN CAPITAL LETTER I (U+0049)
'
'StringComparison.InvariantCultureIgnoreCase:
'LATIN SMALL LETTER I (U+0069) is less than LATIN SMALL LETTER DOTLESS I (U+0131)
'LATIN SMALL LETTER I (U+0069) is equal to LATIN CAPITAL LETTER I (U+0049)
'LATIN SMALL LETTER DOTLESS I (U+0131) is greater than LATIN CAPITAL LETTER I (U+0049)
'
'StringComparison.Ordinal:
'LATIN SMALL LETTER I (U+0069) is less than LATIN SMALL LETTER DOTLESS I (U+0131)
'LATIN SMALL LETTER I (U+0069) is greater than LATIN CAPITAL LETTER I (U+0049)
'LATIN SMALL LETTER DOTLESS I (U+0131) is greater than LATIN CAPITAL LETTER I (U+0049)
'
'StringComparison.OrdinalIgnoreCase:
'LATIN SMALL LETTER I (U+0069) is less than LATIN SMALL LETTER DOTLESS I (U+0131)
'LATIN SMALL LETTER I (U+0069) is equal to LATIN CAPITAL LETTER I (U+0049)
'LATIN SMALL LETTER DOTLESS I (U+0131) is greater than LATIN CAPITAL LETTER I (U+0049)
'

注解

一个或两个比较可以是 null。根据定义，任何字符串（包括空字符串 (“”) ）都比较大于 null 引用;和两个 null 引用相等比较。

static bool IsFileURI(String^ path)
{
    return (String::Compare(path, 0, "file:", 0, 5, true) == 0);
}

static bool IsFileURI(String path)
{
    return (String.Compare(path, 0, "file:", 0, 5, true) == 0);
}

let isFileURI path =
    String.Compare(path, 0, "file:", 0, 5, true) = 0

Shared Function IsFileURI(ByVal path As String) As Boolean
    If String.Compare(path, 0, "file:", 0, 5, True) = 0 Then
        Return True
    Else
        Return False
    End If
End Function

使用序号比较将路径名与“文件”进行比较。执行此操作的正确代码如下所示：

static bool IsFileURI(String^ path)
{
    return (String::Compare(path, 0, "file:", 0, 5, StringComparison::OrdinalIgnoreCase) == 0);
}

static bool IsFileURI(String path)
{
    return (String.Compare(path, 0, "file:", 0, 5, StringComparison.OrdinalIgnoreCase) == 0);
}

let isFileURI path =
    String.Compare(path, 0, "file:", 0, 5, StringComparison.OrdinalIgnoreCase) = 0

Shared Function IsFileURI(ByVal path As String) As Boolean
    If String.Compare(path, 0, "file:", 0, 5, StringComparison.OrdinalIgnoreCase) = 0 Then
        Return True
    Else
        Return False
    End If
End Function

调用方说明

字符集包括可忽略字符。方法 Compare(String, String, StringComparison) 在执行区分区域性的比较时不考虑此类字符。若要识别比较中的可忽略字符，请为 comparisonType 参数提供或 OrdinalIgnoreCase 值Ordinal。

另请参阅

适用于

Compare(String, String, Boolean)

比较两个指定的 String 对象（其中忽略或考虑其大小写），并返回一个整数，指示二者在排序顺序中的相对位置。

public:
 static int Compare(System::String ^ strA, System::String ^ strB, bool ignoreCase);

public static int Compare (string strA, string strB, bool ignoreCase);

public static int Compare (string? strA, string? strB, bool ignoreCase);

static member Compare : string * string * bool -> int

Public Shared Function Compare (strA As String, strB As String, ignoreCase As Boolean) As Integer

参数

strA: String

要比较的第一个字符串。

strB: String

要比较的第二个字符串。

ignoreCase: Boolean

若要在比较过程中忽略大小写，则为 true；否则为 false。

Int32

一个 32 位带符号整数，指示两个比较数之间的词法关系。

“值”	条件
小于零	`strA` 在排序顺序中位于 `strB` 之前。
零	`strA` 与 `strB` 在排序顺序中出现的位置相同。
大于零	`strA` 在排序顺序中位于 `strB` 之后。

示例

以下示例演示 Compare(String, String, Boolean) 方法等效于在比较字符串时使用 ToUpper 或 ToLower 。

using namespace System;

void main()
{
   // Create upper-case characters from their Unicode code units.
   String^ stringUpper = "\x0041\x0042\x0043";

   // Create lower-case characters from their Unicode code units.
   String^ stringLower = "\x0061\x0062\x0063";

   // Display the strings.
   Console::WriteLine("Comparing '{0}' and '{1}':", 
                      stringUpper, stringLower);

   // Compare the uppercased strings; the result is true.
   Console::WriteLine("The Strings are equal when capitalized? {0}",
                      String::Compare(stringUpper->ToUpper(), stringLower->ToUpper()) == 0 
                                      ? "true" : "false");

   // The previous method call is equivalent to this Compare method, which ignores case.
   Console::WriteLine("The Strings are equal when case is ignored? {0}",
                      String::Compare(stringUpper, stringLower, true) == 0
                                      ? "true" : "false");
}
// The example displays the following output:
//       Comparing 'ABC' and 'abc':
//       The Strings are equal when capitalized? true
//       The Strings are equal when case is ignored? true

// Create upper-case characters from their Unicode code units.
String stringUpper = "\x0041\x0042\x0043";

// Create lower-case characters from their Unicode code units.
String stringLower = "\x0061\x0062\x0063";

// Display the strings.
Console.WriteLine("Comparing '{0}' and '{1}':", 
                stringUpper, stringLower);

// Compare the uppercased strings; the result is true.
Console.WriteLine("The Strings are equal when capitalized? {0}",
                String.Compare(stringUpper.ToUpper(), stringLower.ToUpper()) == 0 
                               ? "true" : "false");

// The previous method call is equivalent to this Compare method, which ignores case.
Console.WriteLine("The Strings are equal when case is ignored? {0}",
                String.Compare(stringUpper, stringLower, true) == 0
                               ? "true" : "false" );

// The example displays the following output:
//       Comparing 'ABC' and 'abc':
//       The Strings are equal when capitalized? true
//       The Strings are equal when case is ignored? true

open System

// Create upper-case characters from their Unicode code units.
let stringUpper = "\x0041\x0042\x0043"

// Create lower-case characters from their Unicode code units.
let stringLower = "\x0061\x0062\x0063"

// Display the strings.
printfn $"Comparing '{stringUpper}' and '{stringLower}':"

// Compare the uppercased strings the result is true.
printfn $"The Strings are equal when capitalized? %b{String.Compare(stringUpper.ToUpper(), stringLower.ToUpper()) = 0}"

// The previous method call is equivalent to this Compare method, which ignores case.
printfn $"The Strings are equal when case is ignored? %b{String.Compare(stringUpper, stringLower, true) = 0}"

// The example displays the following output:
//       Comparing 'ABC' and 'abc':
//       The Strings are equal when capitalized? true
//       The Strings are equal when case is ignored? true

Public Module Example
   Public Sub Main()
      ' Create upper-case characters from their Unicode code units.
      Dim stringUpper As String = ChrW(&H41) + ChrW(&H42) + ChrW(&H43)

      ' Create lower-case characters from their Unicode code units.
      Dim stringLower As String = ChrW(&H61) + ChrW(&H62) + ChrW(&H63)

      ' Display the strings.
      Console.WriteLine("Comparing '{0}' and '{1}':", 
                        stringUpper, stringLower)

      ' Compare the uppercased strings; the result is true.
      Console.WriteLine("The Strings are equal when capitalized? {0}",
                        If(String.Compare(stringUpper.ToUpper(), stringLower.ToUpper()) = 0, 
                                          "true", "false"))

      ' The previous method call is equivalent to this Compare method, which ignores case.
      Console.WriteLine("The Strings are equal when case is ignored? {0}",
                        If(String.Compare(stringUpper, stringLower, true) = 0,
                                          "true", "false"))
   End Sub
End Module 
' The example displays the following output:
'       Comparing 'ABC' and 'abc':
'       The Strings are equal when capitalized? true
'       The Strings are equal when case is ignored? true

注解

比较是使用单词排序规则执行的。有关单词、字符串和序号排序的详细信息，请参阅 System.Globalization.CompareOptions。

警告

一个或两个比较可以是 null。根据定义，任何字符串（包括空字符串 (“”) ）都比较大于 null 引用;和两个 null 引用相等比较。

static bool IsFileURI(String^ path)
{
    return (String::Compare(path, 0, "file:", 0, 5, true) == 0);
}

static bool IsFileURI(String path)
{
    return (String.Compare(path, 0, "file:", 0, 5, true) == 0);
}

let isFileURI path =
    String.Compare(path, 0, "file:", 0, 5, true) = 0

Shared Function IsFileURI(ByVal path As String) As Boolean
    If String.Compare(path, 0, "file:", 0, 5, True) = 0 Then
        Return True
    Else
        Return False
    End If
End Function

使用序号比较将路径名与“文件”进行比较。执行此操作的正确代码如下所示：

static bool IsFileURI(String^ path)
{
    return (String::Compare(path, 0, "file:", 0, 5, StringComparison::OrdinalIgnoreCase) == 0);
}

static bool IsFileURI(String path)
{
    return (String.Compare(path, 0, "file:", 0, 5, StringComparison.OrdinalIgnoreCase) == 0);
}

let isFileURI path =
    String.Compare(path, 0, "file:", 0, 5, StringComparison.OrdinalIgnoreCase) = 0

Shared Function IsFileURI(ByVal path As String) As Boolean
    If String.Compare(path, 0, "file:", 0, 5, StringComparison.OrdinalIgnoreCase) = 0 Then
        Return True
    Else
        Return False
    End If
End Function

调用方说明

字符集包括可忽略字符。方法 Compare(String, String, Boolean) 在执行区分区域性的比较时不考虑此类字符。例如，如果以下代码在 .NET Framework 4 或更高版本上运行，则使用软连字符对“animal”与“Ani-mal”进行区分区域性、不区分大小写的比较 (或 U+00AD) 指示这两个字符串是等效的。

string s1 = "Ani\u00ADmal";
string s2 = "animal";

Console.WriteLine("Comparison of '{0}' and '{1}': {2}",
                s1, s2, String.Compare(s1, s2, true));

// The example displays the following output:
//       Comparison of 'Ani-mal' and 'animal': 0

open System

let s1 = "Ani\u00ADmal"
let s2 = "animal"

printfn $"Comparison of '{s1}' and '{s2}': {String.Compare(s1, s2, true)}"

// The example displays the following output:
//       Comparison of 'Ani-mal' and 'animal': 0

Module Example
   Public Sub Main()
      Dim s1 As String = "Ani" + ChrW(&h00AD) + "mal"
      Dim s2 As String = "animal"
      
      Console.WriteLine("Comparison of '{0}' and '{1}': {2}", 
                        s1, s2, String.Compare(s1, s2, True))
  End Sub
End Module
' The example displays the following output:
'       Comparison of 'ani-mal' and 'animal': 0

若要识别字符串比较中的可忽略字符，请调用 Compare(String, String, StringComparison) 方法并为参数提供或 OrdinalIgnoreCasecomparisonType 值Ordinal。

另请参阅

适用于

Compare(String, String, CultureInfo, CompareOptions)

对两个指定的 String 对象进行比较，使用指定的比较选项和区域性特定的信息来影响比较，并返回一个整数，该整数指示这两个字符串在排序顺序中的关系。

public:
 static int Compare(System::String ^ strA, System::String ^ strB, System::Globalization::CultureInfo ^ culture, System::Globalization::CompareOptions options);

public static int Compare (string? strA, string? strB, System.Globalization.CultureInfo? culture, System.Globalization.CompareOptions options);

public static int Compare (string strA, string strB, System.Globalization.CultureInfo culture, System.Globalization.CompareOptions options);

static member Compare : string * string * System.Globalization.CultureInfo * System.Globalization.CompareOptions -> int

Public Shared Function Compare (strA As String, strB As String, culture As CultureInfo, options As CompareOptions) As Integer

参数

strA: String

要比较的第一个字符串。

strB: String

要比较的第二个字符串。

culture: CultureInfo

提供区域性特定的比较信息的区域性。如果 culture 为 null，则使用当前区域性。

options: CompareOptions

要在执行比较时使用的选项（如忽略大小写或符号）。

Int32

一个 32 位带符号整数，该整数指示 strA 与 strB 之间的词法关系，如下表所示

“值”	条件
小于零	`strA` 在排序顺序中位于 `strB` 之前。
零	`strA` 与 `strB` 在排序顺序中出现的位置相同。
大于零	`strA` 在排序顺序中位于 `strB` 之后。

例外

ArgumentException

options 不是 CompareOptions 值。

示例

以下示例以三种不同的方式比较两个字符串：对 en-US 区域性使用语言比较;对 en-US 区域性使用区分大小写的语言比较;并使用序号比较。它说明了三种比较方法如何产生三种不同的结果。

using namespace System;
using namespace System::Globalization;

public ref class Example
{
public:
   static void Main()
   {
      String^ string1 = "brother";
      String^ string2 = "Brother";
      String^ relation;
      int result;

      // Cultural (linguistic) comparison.
      result = String::Compare(string1, string2, gcnew CultureInfo("en-US"),
                              CompareOptions::None);
      if (result > 0)
         relation = "comes after";
      else if (result == 0)
         relation = "is the same as";
      else
         relation = "comes before";

      Console::WriteLine("'{0}' {1} '{2}'.",
                        string1, relation, string2);

      // Cultural (linguistic) case-insensitive comparison.
      result = String::Compare(string1, string2, gcnew CultureInfo("en-US"),
                              CompareOptions::IgnoreCase);
      if (result > 0)
         relation = "comes after";
      else if (result == 0)
         relation = "is the same as";
      else
         relation = "comes before";

      Console::WriteLine("'{0}' {1} '{2}'.",
                        string1, relation, string2);

       // Culture-insensitive ordinal comparison.
      result = String::CompareOrdinal(string1, string2);
      if (result > 0)
         relation = "comes after";
      else if (result == 0)
         relation = "is the same as";
      else
         relation = "comes before";

      Console::WriteLine("'{0}' {1} '{2}'.",
                        string1, relation, string2);
   }
};

int main()
{
    Example::Main();
}


// The example produces the following output:
//    'brother' comes before 'Brother'.
//    'brother' is the same as 'Brother'.
//    'brother' comes after 'Brother'.

using System;
using System.Globalization;

public class Example0
{
    public static void Main()
    {
        string string1 = "brother";
        string string2 = "Brother";
        string relation;
        int result;

        // Cultural (linguistic) comparison.
        result = String.Compare(string1, string2, new CultureInfo("en-US"), 
                              CompareOptions.None);
        if (result > 0)
            relation = "comes after";
        else if (result == 0)
            relation = "is the same as";
        else
            relation = "comes before";

        Console.WriteLine("'{0}' {1} '{2}'.", 
                        string1, relation, string2);

        // Cultural (linguistic) case-insensitive comparison.
        result = String.Compare(string1, string2, new CultureInfo("en-US"), 
                              CompareOptions.IgnoreCase);
        if (result > 0)
            relation = "comes after";
        else if (result == 0)
            relation = "is the same as";
        else
            relation = "comes before";

        Console.WriteLine("'{0}' {1} '{2}'.", 
                        string1, relation, string2);
 
        // Culture-insensitive ordinal comparison.
        result = String.CompareOrdinal(string1, string2);
        if (result > 0)
            relation = "comes after";
        else if (result == 0)
            relation = "is the same as";
        else
            relation = "comes before";

        Console.WriteLine("'{0}' {1} '{2}'.", 
                        string1, relation, string2);

        // The example produces the following output:
        //    'brother' comes before 'Brother'.   
        //    'brother' is the same as 'Brother'.
        //    'brother' comes after 'Brother'.
    }
}

open System
open System.Globalization

let string1 = "brother"
let string2 = "Brother"

// Cultural (linguistic) comparison.
let result = String.Compare(string1, string2, CultureInfo "en-US", CompareOptions.None)
let relation =
    if result > 0 then "comes after"
    elif result = 0 then "is the same as"
    else "comes before"

printfn $"'{string1}' {relation} '{string2}'."

// Cultural (linguistic) case-insensitive comparison.
let result2 = String.Compare(string1, string2, CultureInfo "en-US", CompareOptions.IgnoreCase)
let relation2 =
    if result2 > 0 then "comes after"
    elif result2 = 0 then "is the same as"
    else "comes before"

printfn $"'{string1}' {relation2} '{string2}'."

// Culture-insensitive ordinal comparison.
let result3 = String.CompareOrdinal(string1, string2)
let relation3 =
    if result2 > 0 then "comes after"
    elif result2 = 0 then "is the same as"
    else "comes before"

printfn $"'{string1}' {relation} '{string2}'."

// The example produces the following output:
//    'brother' comes before 'Brother'.   
//    'brother' is the same as 'Brother'.
//    'brother' comes after 'Brother'.

Imports System.Globalization

Public Module Example
   Public Sub Main()
      Dim string1 As String = "brother"
      Dim string2 As String = "Brother"
      Dim relation As String
      Dim result As Integer

      ' Cultural (linguistic) comparison.
      result = String.Compare(string1, string2, _
                              New CultureInfo("en-US"), CompareOptions.None)
      If result > 0 Then
         relation = "comes after"
      ElseIf result = 0 Then
         relation = "is the same as"
      Else
         relation = "comes before"
      End If
      Console.WriteLine("'{0}' {1} '{2}'.", string1, relation, string2)

      ' Cultural (linguistic) case-insensitive comparison.
      result = String.Compare(string1, string2, _
                              New CultureInfo("en-US"), CompareOptions.IgnoreCase)
      If result > 0 Then
         relation = "comes after"
      ElseIf result = 0 Then
         relation = "is the same as"
      Else
         relation = "comes before"
      End If
      Console.WriteLine("'{0}' {1} '{2}'.", string1, relation, string2)

      ' Culture-insensitive ordinal comparison.
      result = String.CompareOrdinal(string1, string2)
      If result > 0 Then
         relation = "comes after"
      ElseIf result = 0 Then
         relation = "is the same as"
      Else
         relation = "comes before"
      End If
      Console.WriteLine("'{0}' {1} '{2}'.", string1, relation, string2)
   End Sub
End Module
' The example produces the following output:
'    'brother' comes before 'Brother'.   
'    'brother' is the same as 'Brother'.
'    'brother' comes after 'Brother'.

注解

注意

方法 Compare(String, String, CultureInfo, CompareOptions) 主要用于排序或按字母顺序排列操作。当方法调用的主要用途是确定两个字符串是否等效 (即方法调用的目的是测试零) 的返回值时，不应使用此方法。若要确定两个字符串是否等效，请调用 Equals 方法。

可以通过参数进一步指定 options 比较，该参数由枚举的 CompareOptions 一个或多个成员组成。但是，由于此方法的目的是执行区分区域性的字符串比较， CompareOptions.Ordinal 因此和 CompareOptions.OrdinalIgnoreCase 值不起作用。

任一比较或两个比较都可以是 null。根据定义，任何字符串（包括 String.Empty）都会比较大于 null 引用，而两个 null 引用比较彼此相等。

当发现不相等或已比较两个字符串时，比较终止。但是，如果两个字符串的比较等于一个字符串的末尾，而另一个字符串有剩余的字符，则具有剩余字符的字符串被视为更大。

调用方说明

字符集包括可忽略字符，在执行语言性的或区分区域性的比较时该字符不被考虑。方法 Compare(String, String, CultureInfo, CompareOptions) 在执行区分区域性的比较时不考虑此类字符。若要识别比较中的可忽略字符，请为 options 参数提供或 OrdinalIgnoreCase 值Ordinal。

另请参阅

适用于