String.Concat 方法

定义

命名空间:

System

程序集:

netstandard.dll, System.Runtime.dll

连接一个或多个实例 String，或 String 一个或多个实例 Object的值表示形式。

重载

名称	说明
Concat(String, String, String, String)	连接四个 String指定的实例。
Concat(ReadOnlySpan<Char>, ReadOnlySpan<Char>, ReadOnlySpan<Char>, ReadOnlySpan<Char>)	连接四个指定的只读字符范围的字符串表示形式。
Concat(String, String, String)	连接三个 String指定的实例。
Concat(ReadOnlySpan<Char>, ReadOnlySpan<Char>, ReadOnlySpan<Char>)	连接三个指定的只读字符范围的字符串表示形式。
Concat(Object, Object, Object)	连接三个指定对象的字符串表示形式。
Concat(String, String)	连接两个 String指定的实例 。
Concat(ReadOnlySpan<Object>)	连接指定对象范围中元素的字符串表示形式。
Concat(Object, Object)	连接两个指定对象的字符串表示形式。
Concat(String[])	连接指定 String 数组的元素。
Concat(ReadOnlySpan<String>)	连接指定范围中的 String元素。
Concat(Object[])	连接指定 Object 数组中元素的字符串表示形式。
Concat(Object)	创建指定对象的字符串表示形式。
Concat(IEnumerable<String>)	连接类型String构造IEnumerable<T>集合的成员。
Concat(ReadOnlySpan<Char>, ReadOnlySpan<Char>)	连接两个指定的只读字符范围的字符串表示形式。
Concat<T>(IEnumerable<T>)	连接实现的成员 IEnumerable<T> 。

注解

注意

还可以使用语言的字符串串联运算符（如 + C# 和 F# 或 &+ Visual Basic）连接字符串。 两个编译器将串联运算符转换为对其中一个重载的 String.Concat调用。

Concat(String, String, String, String)

Source:

String.Manipulation.cs

连接四个 String指定的实例。

public:
 static System::String ^ Concat(System::String ^ str0, System::String ^ str1, System::String ^ str2, System::String ^ str3);

public static string Concat(string? str0, string? str1, string? str2, string? str3);

static member Concat : string * string * string * string -> string

Public Shared Function Concat (str0 As String, str1 As String, str2 As String, str3 As String) As String

参数

str0

String

要连接的第一个字符串。

str1

String

要连接的第二个字符串。

str2

String

要连接的第三个字符串。

str3

String

要连接的第四个字符串。

返回

String

和 . 的str0str1str2str3串联。

示例

下面的示例定义一个由四个字母单词表示的数组，并将其单个字母存储在字符串数组中，以便对其进行争用。 然后，它调用 Concat(String, String, String, String) 该方法来重新组合争用的单词。

using System;
using System.Collections;

public class Example
{
   public static void Main()
   {
      const int WORD_SIZE = 4;
      
      // Define some 4-letter words to be scrambled.
      string[] words = { "home", "food", "game", "rest" };
      // Define two arrays equal to the number of letters in each word.
      double[] keys = new double[WORD_SIZE];
      string[] letters = new string[WORD_SIZE];
      // Initialize the random number generator.
      Random rnd = new Random();
      
      // Scramble each word.
      foreach (string word in words)
      {
         for (int ctr = 0; ctr < word.Length; ctr++)
         {
            // Populate the array of keys with random numbers.
            keys[ctr] = rnd.NextDouble();
            // Assign a letter to the array of letters.
            letters[ctr] = word[ctr].ToString();
         }   
         // Sort the array. 
         Array.Sort(keys, letters, 0, WORD_SIZE, Comparer.Default);      
         // Display the scrambled word.
         string scrambledWord = String.Concat(letters[0], letters[1], 
                                              letters[2], letters[3]);
         Console.WriteLine("{0} --> {1}", word, scrambledWord);
      } 
   }
}
// The example displays output like the following:
//       home --> mheo
//       food --> oodf
//       game --> aemg
//       rest --> trse

open System
open System.Collections

let WORD_SIZE = 4
      
// Define some 4-letter words to be scrambled.
let words = [| "home"; "food"; "game"; "rest" |]
// Define two arrays equal to the number of letters in each word.
let keys = Array.zeroCreate<float> WORD_SIZE
let letters = Array.zeroCreate<string> WORD_SIZE
// Initialize the random number generator.
let rnd = Random()

// Scramble each word.
for word in words do
    for i = 0 to word.Length - 1 do
        // Populate the array of keys with random numbers.
        keys[i] <- rnd.NextDouble()
        // Assign a letter to the array of letters.
        letters[i] <- string word[i]
    // Sort the array. 
    Array.Sort(keys, letters, 0, WORD_SIZE, Comparer.Default)      
    // Display the scrambled word.
    let scrambledWord = String.Concat(letters[0], letters[1], letters[2], letters[3])
    printfn $"{word} --> {scrambledWord}"
// The example displays output like the following:
//       home --> mheo
//       food --> oodf
//       game --> aemg
//       rest --> trse

Imports System.Collections

Module Example
   Public Sub Main()
      Const WORD_SIZE As Integer = 4
      
      ' Define some 4-letter words to be scrambled.
      Dim words() As String = { "home", "food", "game", "rest" }
      ' Define two arrays equal to the number of letters in each word.
      Dim keys(WORD_SIZE) As Double
      Dim letters(WORD_SIZE) As String
      ' Initialize the random number generator.
      Dim rnd As New Random()
      
      ' Scramble each word.
      For Each word As String In words
         For ctr As Integer = 0 To word.Length - 1
            ' Populate the array of keys with random numbers.
            keys(ctr) = rnd.NextDouble()
            ' Assign a letter to the array of letters.
            letters(ctr) = word.Chars(ctr)
         Next   
         ' Sort the array. 
         Array.Sort(keys, letters, 0, WORD_SIZE, Comparer.Default)      
         ' Display the scrambled word.
         Dim scrambledWord As String = String.Concat(letters(0), letters(1), _
                                                     letters(2), letters(3))
         Console.WriteLine("{0} --> {1}", word, scrambledWord)
      Next 
   End Sub
End Module 
' The example displays output like the following:
'       home --> mheo
'       food --> oodf
'       game --> aemg
'       rest --> trse

注解

该方法连接 str0，str1str2并且str3它不添加任何分隔符。

另请参阅

• Join(String, String[])

Concat(ReadOnlySpan<Char>, ReadOnlySpan<Char>, ReadOnlySpan<Char>, ReadOnlySpan<Char>)

Source:

String.Manipulation.cs

连接四个指定的只读字符范围的字符串表示形式。

public:
 static System::String ^ Concat(ReadOnlySpan<char> str0, ReadOnlySpan<char> str1, ReadOnlySpan<char> str2, ReadOnlySpan<char> str3);

public static string Concat(ReadOnlySpan<char> str0, ReadOnlySpan<char> str1, ReadOnlySpan<char> str2, ReadOnlySpan<char> str3);

static member Concat : ReadOnlySpan<char> * ReadOnlySpan<char> * ReadOnlySpan<char> * ReadOnlySpan<char> -> string

Public Shared Function Concat (str0 As ReadOnlySpan(Of Char), str1 As ReadOnlySpan(Of Char), str2 As ReadOnlySpan(Of Char), str3 As ReadOnlySpan(Of Char)) As String

参数

str0

ReadOnlySpan<Char>

要连接的第一个只读字符范围。

str1

ReadOnlySpan<Char>

要连接的第二个只读字符范围。

str2

ReadOnlySpan<Char>

要连接的第三个只读字符范围。

str3

ReadOnlySpan<Char>

要连接的第四个只读字符范围。

返回

String

值str0str1str2和str3值的串联字符串表示形式。

Concat(String, String, String)

Source:

String.Manipulation.cs

连接三个 String指定的实例。

public:
 static System::String ^ Concat(System::String ^ str0, System::String ^ str1, System::String ^ str2);

public static string Concat(string? str0, string? str1, string? str2);

static member Concat : string * string * string -> string

Public Shared Function Concat (str0 As String, str1 As String, str2 As String) As String

参数

str0

String

要连接的第一个字符串。

str1

String

要连接的第二个字符串。

str2

String

要连接的第三个字符串。

返回

String

和 str2. 的str0str1串联。

示例

以下示例使用 Concat 该方法连接三个字符串并显示结果。

using System;

public class Example
{
   public static void Main()
   {
      String s1 = "We went to a bookstore, ";
      String s2 = "a movie, ";
      String s3 = "and a restaurant.";

      var s = String.Concat(s1, s2, s3);
      Console.WriteLine(s);
   }
}
// The example displays the following output:
//      We went to a bookstore, a movie, and a restaurant.

open System

let s1 = "We went to a bookstore, "
let s2 = "a movie, "
let s3 = "and a restaurant."

String.Concat(s1, s2, s3)
|> printfn "%s"
// The example displays the following output:
//      We went to a bookstore, a movie, and a restaurant.

Public Module Example
   Public Sub Main()
      Dim s1 As String = "We went to a bookstore, "
      Dim s2 As String = "a movie, "
      Dim s3 As String = "and a restaurant."

      Dim s = String.Concat(s1, s2, s3)
      Console.WriteLine(s)
   End Sub
End Module
' The example displays the following output:
'      We went to a bookstore, a movie, and a restaurant.

注解

该方法连接 str0， str1并且 str2不添加任何分隔符。

另请参阅

• Join(String, String[])

Concat(ReadOnlySpan<Char>, ReadOnlySpan<Char>, ReadOnlySpan<Char>)

Source:

String.Manipulation.cs

连接三个指定的只读字符范围的字符串表示形式。

public:
 static System::String ^ Concat(ReadOnlySpan<char> str0, ReadOnlySpan<char> str1, ReadOnlySpan<char> str2);

public static string Concat(ReadOnlySpan<char> str0, ReadOnlySpan<char> str1, ReadOnlySpan<char> str2);

static member Concat : ReadOnlySpan<char> * ReadOnlySpan<char> * ReadOnlySpan<char> -> string

Public Shared Function Concat (str0 As ReadOnlySpan(Of Char), str1 As ReadOnlySpan(Of Char), str2 As ReadOnlySpan(Of Char)) As String

参数

str0

ReadOnlySpan<Char>

要连接的第一个只读字符范围。

str1

ReadOnlySpan<Char>

要连接的第二个只读字符范围。

str2

ReadOnlySpan<Char>

要连接的第三个只读字符范围。

返回

String

值和str2值的串联字符串表示形式。str0str1

Concat(Object, Object, Object)

Source:

String.Manipulation.cs

连接三个指定对象的字符串表示形式。

public:
 static System::String ^ Concat(System::Object ^ arg0, System::Object ^ arg1, System::Object ^ arg2);

public static string Concat(object? arg0, object? arg1, object? arg2);

static member Concat : obj * obj * obj -> string

Public Shared Function Concat (arg0 As Object, arg1 As Object, arg2 As Object) As String

参数

arg0

Object

要连接的第一个对象。

arg1

Object

要连接的第二个对象。

arg2

Object

要连接的第三个对象。

返回

String

值arg0arg1和arg2值的串联字符串表示形式。

示例

以下示例演示了该方法 Concat 。

using System;

class stringConcat5 {
    public static void Main() {
    int i = -123;
    Object o = i;
    Object[] objs = new Object[] {-123, -456, -789};

    Console.WriteLine("Concatenate 1, 2, and 3 objects:");
    Console.WriteLine("1) {0}", String.Concat(o));
    Console.WriteLine("2) {0}", String.Concat(o, o));
    Console.WriteLine("3) {0}", String.Concat(o, o, o));

    Console.WriteLine("\nConcatenate 4 objects and a variable length parameter list:");
    Console.WriteLine("4) {0}", String.Concat(o, o, o, o));
    Console.WriteLine("5) {0}", String.Concat(o, o, o, o, o));

    Console.WriteLine("\nConcatenate a 3-element object array:");
    Console.WriteLine("6) {0}", String.Concat(objs));
    }
}
// The example displays the following output:
//    Concatenate 1, 2, and 3 objects:
//    1) -123
//    2) -123-123
//    3) -123-123-123
//
//    Concatenate 4 objects and a variable length parameter list:
//    4) -123-123-123-123
//    5) -123-123-123-123-123
//
//    Concatenate a 3-element object array:
//    6) -123-456-789

open System

let i = -123
let o: obj = i
let objs: obj[] = [| -123; -456; -789 |]

printfn "Concatenate 1, 2, and 3 objects:"
printfn $"1) {String.Concat o}"
printfn $"2) {String.Concat(o, o)}"
printfn $"3) {String.Concat(o, o, o)}"

printfn "\nConcatenate 4 objects and a variable length parameter list:"
printfn $"4) {String.Concat(o, o, o, o)}"
printfn $"5) {String.Concat(o, o, o, o, o)}"

printfn "\nConcatenate a 3-element object array:"
printfn $"6) {String.Concat objs}" 
// The example displays the following output:
//    Concatenate 1, 2, and 3 objects:
//    1) -123
//    2) -123-123
//    3) -123-123-123
//
//    Concatenate 4 objects and a variable length parameter list:
//    4) -123-123-123-123
//    5) -123-123-123-123-123
//
//    Concatenate a 3-element object array:
//    6) -123-456-789

Class stringConcat5
   Public Shared Sub Main()
      Dim i As Integer = - 123
      Dim o As [Object] = i
      Dim objs() As [Object] = {-123, -456, -789}
      
      Console.WriteLine("Concatenate 1, 2, and 3 objects:")
      Console.WriteLine("1) {0}", [String].Concat(o))
      Console.WriteLine("2) {0}", [String].Concat(o, o))
      Console.WriteLine("3) {0}", [String].Concat(o, o, o))
      
      Console.WriteLine(vbCrLf & "Concatenate 4 objects and a variable length parameter list:")
      Console.WriteLine("4) {0}", String.Concat(o, o, o, o))
      Console.WriteLine("5) {0}", String.Concat(o, o, o, o, o))
      
      Console.WriteLine(vbCrLf & "Concatenate a 3-element object array:")
      Console.WriteLine("6) {0}", [String].Concat(objs))
   End Sub
End Class
'The example displays the following output:
'    Concatenate 1, 2, and 3 objects:
'    1) -123
'    2) -123-123
'    3) -123-123-123
'    
'    Concatenate 4 objects and a variable length parameter list:
'    4) -123-123-123-123
'    5) -123-123-123-123-123
'         
'    Concatenate a 3-element object array:
'    6) -123-456-789

注解

该方法连接 arg0， arg1并通过 arg2 调用每个对象的无 ToString 参数方法;它不添加任何分隔符。

String.Empty 用于代替任何 null 参数。

另请参阅

• Object
• Join(String, String[])

Concat(String, String)

Source:

String.Manipulation.cs

连接两个 String指定的实例 。

public:
 static System::String ^ Concat(System::String ^ str0, System::String ^ str1);

public static string Concat(string? str0, string? str1);

static member Concat : string * string -> string

Public Shared Function Concat (str0 As String, str1 As String) As String

参数

str0

String

要连接的第一个字符串。

str1

String

要连接的第二个字符串。

返回

String

和 str1. 的str0串联。

示例

以下示例连接某人的第一个、中间和姓氏。

using System;

public class ConcatTest {
    public static void Main() {

        // we want to simply quickly add this person's name together
        string fName = "Simon";
        string mName = "Jake";
        string lName = "Harrows";

        // because we want a name to appear with a space in between each name,
        // put a space on the front of the middle, and last name, allowing for
        // the fact that a space may already be there
        mName = " " + mName.Trim();
        lName = " " + lName.Trim();

        // this line simply concatenates the two strings
        Console.WriteLine("Welcome to this page, '{0}'!", string.Concat( string.Concat(fName, mName), lName ) );
    }
}
// The example displays the following output:
//        Welcome to this page, 'Simon Jake Harrows'!

open System

[<EntryPoint>]
let main _ =
    // we want to simply quickly add this person's name together
    let fName = "Simon"
    let mName = "Jake"
    let lName = "Harrows"

    // because we want a name to appear with a space in between each name,
    // put a space on the front of the middle, and last name, allowing for
    // the fact that a space may already be there
    let mName = " " + mName.Trim()
    let lName = " " + lName.Trim()

    // this line simply concatenates the two strings
    printfn $"Welcome to this page, '{String.Concat(String.Concat(fName, mName), lName)}'!"
    0
// The example displays the following output:
//        Welcome to this page, 'Simon Jake Harrows'!

Public Class ConcatTest
    Public Shared Sub Main()
        Dim fName As String = "Simon"
        Dim mName As String = "Jake"
        Dim lName As String = "Harrows"
        
        ' We want to simply quickly add this person's name together.
        ' Because we want a name to appear with a space in between each name, 
        ' we put a space on the front of the middle, and last name, allowing for
        ' the fact that a space may already be there.
        mName = " " + mName.Trim()
        lName = " " + lName.Trim()
        
        ' This line simply concatenates the two strings.
        Console.WriteLine("Welcome to this page, '{0}'!", _
                          String.Concat(String.Concat(fName, mName), lName))
    End Sub
End Class
' The example displays the following output:
'       Welcome to this page, 'Simon Jake Harrows'!

注解

该方法连接 str0 并 str1;它不添加任何分隔符。

Empty字符串用于代替任何 null 参数。

另请参阅

• Join(String, String[])

Concat(ReadOnlySpan<Object>)

Source:

String.Manipulation.cs

连接指定对象范围中元素的字符串表示形式。

public:
 static System::String ^ Concat(ReadOnlySpan<System::Object ^> args);

public static string Concat(scoped ReadOnlySpan<object?> args);

static member Concat : ReadOnlySpan<obj> -> string

Public Shared Function Concat (args As ReadOnlySpan(Of Object)) As String

参数

args

ReadOnlySpan<Object>

包含要连接的元素的对象范围。

返回

String

元素值的 args串联字符串表示形式。

Concat(Object, Object)

Source:

String.Manipulation.cs

连接两个指定对象的字符串表示形式。

public:
 static System::String ^ Concat(System::Object ^ arg0, System::Object ^ arg1);

public static string Concat(object? arg0, object? arg1);

static member Concat : obj * obj -> string

Public Shared Function Concat (arg0 As Object, arg1 As Object) As String

参数

arg0

Object

要连接的第一个对象。

arg1

Object

要连接的第二个对象。

返回

String

值 arg0 和 arg1. 的串联字符串表示形式。

示例

以下示例演示了该方法 Concat 。

using System;

class stringConcat5 {
    public static void Main() {
    int i = -123;
    Object o = i;
    Object[] objs = new Object[] {-123, -456, -789};

    Console.WriteLine("Concatenate 1, 2, and 3 objects:");
    Console.WriteLine("1) {0}", String.Concat(o));
    Console.WriteLine("2) {0}", String.Concat(o, o));
    Console.WriteLine("3) {0}", String.Concat(o, o, o));

    Console.WriteLine("\nConcatenate 4 objects and a variable length parameter list:");
    Console.WriteLine("4) {0}", String.Concat(o, o, o, o));
    Console.WriteLine("5) {0}", String.Concat(o, o, o, o, o));

    Console.WriteLine("\nConcatenate a 3-element object array:");
    Console.WriteLine("6) {0}", String.Concat(objs));
    }
}
// The example displays the following output:
//    Concatenate 1, 2, and 3 objects:
//    1) -123
//    2) -123-123
//    3) -123-123-123
//
//    Concatenate 4 objects and a variable length parameter list:
//    4) -123-123-123-123
//    5) -123-123-123-123-123
//
//    Concatenate a 3-element object array:
//    6) -123-456-789

open System

let i = -123
let o: obj = i
let objs: obj[] = [| -123; -456; -789 |]

printfn "Concatenate 1, 2, and 3 objects:"
printfn $"1) {String.Concat o}"
printfn $"2) {String.Concat(o, o)}"
printfn $"3) {String.Concat(o, o, o)}"

printfn "\nConcatenate 4 objects and a variable length parameter list:"
printfn $"4) {String.Concat(o, o, o, o)}"
printfn $"5) {String.Concat(o, o, o, o, o)}"

printfn "\nConcatenate a 3-element object array:"
printfn $"6) {String.Concat objs}" 
// The example displays the following output:
//    Concatenate 1, 2, and 3 objects:
//    1) -123
//    2) -123-123
//    3) -123-123-123
//
//    Concatenate 4 objects and a variable length parameter list:
//    4) -123-123-123-123
//    5) -123-123-123-123-123
//
//    Concatenate a 3-element object array:
//    6) -123-456-789

Class stringConcat5
   Public Shared Sub Main()
      Dim i As Integer = - 123
      Dim o As [Object] = i
      Dim objs() As [Object] = {-123, -456, -789}
      
      Console.WriteLine("Concatenate 1, 2, and 3 objects:")
      Console.WriteLine("1) {0}", [String].Concat(o))
      Console.WriteLine("2) {0}", [String].Concat(o, o))
      Console.WriteLine("3) {0}", [String].Concat(o, o, o))
      
      Console.WriteLine(vbCrLf & "Concatenate 4 objects and a variable length parameter list:")
      Console.WriteLine("4) {0}", String.Concat(o, o, o, o))
      Console.WriteLine("5) {0}", String.Concat(o, o, o, o, o))
      
      Console.WriteLine(vbCrLf & "Concatenate a 3-element object array:")
      Console.WriteLine("6) {0}", [String].Concat(objs))
   End Sub
End Class
'The example displays the following output:
'    Concatenate 1, 2, and 3 objects:
'    1) -123
'    2) -123-123
'    3) -123-123-123
'    
'    Concatenate 4 objects and a variable length parameter list:
'    4) -123-123-123-123
'    5) -123-123-123-123-123
'         
'    Concatenate a 3-element object array:
'    6) -123-456-789

注解

该方法连接 arg0 并 arg1 调用无 ToString 参数方法 arg0 ; arg1它不添加任何分隔符。

String.Empty 用于代替任何 null 参数。

如果任一参数是数组引用，该方法将连接表示该数组的字符串，而不是其成员（例如“System.String[]”）。

另请参阅

• Object
• Join(String, String[])

Concat(String[])

Source:

String.Manipulation.cs

重要

此 API 不符合 CLS。

连接指定 String 数组的元素。

public:
 static System::String ^ Concat(... cli::array <System::String ^> ^ values);

public static string Concat(params string?[] values);

static member Concat : string[] -> string

Public Shared Function Concat (ParamArray values As String()) As String

参数

values

String[]

字符串实例数组。

返回

String

的串联元素 values。

例外

ArgumentNullException

values 是 null。

OutOfMemoryException

内存不足。

示例

以下示例演示如何 Concat 将方法与数组一 String 起使用。

using System;

public class Example
{
    public static void Main()
    {
        // Make an array of strings. Note that we have included spaces.
        string [] s = { "hello ", "and ", "welcome ", "to ",
                        "this ", "demo! " };

        // Put all the strings together.
        Console.WriteLine(string.Concat(s));

        // Sort the strings, and put them together.
        Array.Sort(s);
        Console.WriteLine(string.Concat(s));
    }
}
// The example displays the following output:
//       hello and welcome to this demo!
//       and demo! hello this to welcome

open System

// Make an array of strings. Note that we have included spaces.
let s = 
    [| "hello "; "and "; "welcome "; "to "
       "this "; "demo! " |]

// Put all the strings together.
printfn $"{String.Concat s}"

// Sort the strings, and put them together.
Array.Sort s
printfn $"{String.Concat s}"
// The example displays the following output:
//       hello and welcome to this demo!
//       and demo! hello this to welcome

Public Class Example
    Public Shared Sub Main()
        ' Make an array of strings. Note that we have included spaces.
        Dim s As String() = { "hello ", "and ", "welcome ", "to ",
                              "this ", "demo! "}

        ' Put all the strings together.
        Console.WriteLine(String.Concat(s))
        
        ' Sort the strings, and put them together.
        Array.Sort(s)
        Console.WriteLine(String.Concat(s))
    End Sub
End Class
' The example displays the following output:
'       hello and welcome to this demo!
'       and demo! hello this to welcome

注解

该方法连接每个 values对象;它不添加任何分隔符。

Empty字符串用于代替数组中的任何 null 对象。

另请参阅

• Join(String, String[])

Concat(ReadOnlySpan<String>)

Source:

String.Manipulation.cs

连接指定范围中的 String元素。

public:
 static System::String ^ Concat(ReadOnlySpan<System::String ^> values);

public static string Concat(scoped ReadOnlySpan<string?> values);

static member Concat : ReadOnlySpan<string> -> string

Public Shared Function Concat (values As ReadOnlySpan(Of String)) As String

参数

values

ReadOnlySpan<String>

实例范围 String 。

返回

String

的串联元素 values。

Concat(Object[])

Source:

String.Manipulation.cs

连接指定 Object 数组中元素的字符串表示形式。

public:
 static System::String ^ Concat(... cli::array <System::Object ^> ^ args);

public static string Concat(params object?[] args);

static member Concat : obj[] -> string

Public Shared Function Concat (ParamArray args As Object()) As String

参数

args

Object[]

一个对象数组，其中包含要连接的元素。

返回

String

元素值的 args串联字符串表示形式。

例外

ArgumentNullException

args 是 null。

OutOfMemoryException

内存不足。

示例

下面的示例演示如何 Concat 将方法与数组一 Object 起使用。

using System;

public class ConcatTest {
    public static void Main() {
        // Create a group of objects.
        Test1 t1 = new Test1();
        Test2 t2 = new Test2();
        int i = 16;
        string s = "Demonstration";

        // Place the objects in an array.
        object [] o = { t1, i, t2, s };

        // Concatenate the objects together as a string. To do this,
        // the ToString method of each of the objects is called.
        Console.WriteLine(string.Concat(o));
    }
}

// Create two empty test classes.
class Test1 {
}

class Test2 {
}
// The example displays the following output:
//       Test116Test2Demonstration

open System

// Create two empty test classes.
type Test1() = class end

type Test2() = class end

// Create a group of objects.
let t1 = new Test1()
let t2 = new Test2()
let i = 16
let s = "Demonstration"

// Place the objects in an array.
let o: obj[] = [| t1; i; t2; s |]

// Concatenate the objects together as a string. To do this,
// the ToString method of each of the objects is called.
printfn $"{String.Concat o}"

// The example displays the following output:
//       Test116Test2Demonstration

Public Class ConcatTest
    
    Public Shared Sub Main()
        Dim t1 As New Test1()
        Dim t2 As New Test2()
        Dim i As Integer = 16
        Dim s As String = "Demonstration"
        Dim o As Object() = {t1, i, t2, s}
        
        ' create a group of objects
        
        ' place the objects in an array
        
        ' concatenate the objects together as a string. To do this,
        ' the ToString method in the objects is called
        Console.WriteLine(String.Concat(o))
    End Sub
End Class


' imagine these test classes are full-fledged objects...
Class Test1
End Class

Class Test2
End Class

注解

该方法通过调用该对象的无ToString参数方法连接每个args对象;它不添加任何分隔符。

String.Empty 用于代替数组中的任何 null 对象。

调用方说明

C++代码不调用此方法。 C++ 编译器将调用解析为调用具有四个或多个对象参数的调用ConcatConcat(Object, Object, Object, Object)。

另请参阅

• Object
• Join(String, String[])

Concat(Object)

Source:

String.Manipulation.cs

创建指定对象的字符串表示形式。

public:
 static System::String ^ Concat(System::Object ^ arg0);

public static string Concat(object? arg0);

static member Concat : obj -> string

Public Shared Function Concat (arg0 As Object) As String

参数

arg0

Object

要表示的对象，或 null。

返回

String

值的 arg0字符串表示形式，或者 Empty 如果 arg0 为 null。

示例

以下示例演示了该方法 Concat 。

using System;

class stringConcat5 {
    public static void Main() {
    int i = -123;
    Object o = i;
    Object[] objs = new Object[] {-123, -456, -789};

    Console.WriteLine("Concatenate 1, 2, and 3 objects:");
    Console.WriteLine("1) {0}", String.Concat(o));
    Console.WriteLine("2) {0}", String.Concat(o, o));
    Console.WriteLine("3) {0}", String.Concat(o, o, o));

    Console.WriteLine("\nConcatenate 4 objects and a variable length parameter list:");
    Console.WriteLine("4) {0}", String.Concat(o, o, o, o));
    Console.WriteLine("5) {0}", String.Concat(o, o, o, o, o));

    Console.WriteLine("\nConcatenate a 3-element object array:");
    Console.WriteLine("6) {0}", String.Concat(objs));
    }
}
// The example displays the following output:
//    Concatenate 1, 2, and 3 objects:
//    1) -123
//    2) -123-123
//    3) -123-123-123
//
//    Concatenate 4 objects and a variable length parameter list:
//    4) -123-123-123-123
//    5) -123-123-123-123-123
//
//    Concatenate a 3-element object array:
//    6) -123-456-789

open System

let i = -123
let o: obj = i
let objs: obj[] = [| -123; -456; -789 |]

printfn "Concatenate 1, 2, and 3 objects:"
printfn $"1) {String.Concat o}"
printfn $"2) {String.Concat(o, o)}"
printfn $"3) {String.Concat(o, o, o)}"

printfn "\nConcatenate 4 objects and a variable length parameter list:"
printfn $"4) {String.Concat(o, o, o, o)}"
printfn $"5) {String.Concat(o, o, o, o, o)}"

printfn "\nConcatenate a 3-element object array:"
printfn $"6) {String.Concat objs}" 
// The example displays the following output:
//    Concatenate 1, 2, and 3 objects:
//    1) -123
//    2) -123-123
//    3) -123-123-123
//
//    Concatenate 4 objects and a variable length parameter list:
//    4) -123-123-123-123
//    5) -123-123-123-123-123
//
//    Concatenate a 3-element object array:
//    6) -123-456-789

Class stringConcat5
   Public Shared Sub Main()
      Dim i As Integer = - 123
      Dim o As [Object] = i
      Dim objs() As [Object] = {-123, -456, -789}
      
      Console.WriteLine("Concatenate 1, 2, and 3 objects:")
      Console.WriteLine("1) {0}", [String].Concat(o))
      Console.WriteLine("2) {0}", [String].Concat(o, o))
      Console.WriteLine("3) {0}", [String].Concat(o, o, o))
      
      Console.WriteLine(vbCrLf & "Concatenate 4 objects and a variable length parameter list:")
      Console.WriteLine("4) {0}", String.Concat(o, o, o, o))
      Console.WriteLine("5) {0}", String.Concat(o, o, o, o, o))
      
      Console.WriteLine(vbCrLf & "Concatenate a 3-element object array:")
      Console.WriteLine("6) {0}", [String].Concat(objs))
   End Sub
End Class
'The example displays the following output:
'    Concatenate 1, 2, and 3 objects:
'    1) -123
'    2) -123-123
'    3) -123-123-123
'    
'    Concatenate 4 objects and a variable length parameter list:
'    4) -123-123-123-123
'    5) -123-123-123-123-123
'         
'    Concatenate a 3-element object array:
'    6) -123-456-789

注解

该方法Concat(Object)通过调用其无ToString参数方法表示arg0为字符串。

另请参阅

• Object
• Join(String, String[])

Concat(IEnumerable<String>)

Source:

String.Manipulation.cs

连接类型String构造IEnumerable<T>集合的成员。

public:
 static System::String ^ Concat(System::Collections::Generic::IEnumerable<System::String ^> ^ values);

public static string Concat(System.Collections.Generic.IEnumerable<string?> values);

static member Concat : seq<string> -> string

Public Shared Function Concat (values As IEnumerable(Of String)) As String

参数

values

IEnumerable<String>

实现泛型类型参数及其泛型类型参数的String集合对象IEnumerable<T>。

返回

String

串联字符串（values如果Emptyvalues为空IEnumerable(Of String)）。

例外

ArgumentNullException

values 是 null。

示例

以下示例使用 Eratosthenes 算法的 Sieve 计算小于或等于 100 的质数。 它将结果分配给 List<T> 类型 String对象，然后 Concat(IEnumerable<String>) 传递给该方法。

using System;
using System.Collections.Generic;

public class Example
{
   public static void Main()
   {
      int maxPrime = 100;
      IEnumerable<String> primeList = GetPrimes(maxPrime);
      Console.WriteLine("Primes less than {0}:", maxPrime);
      Console.WriteLine("   {0}", String.Concat(primeList));
   }

   private static IEnumerable<String> GetPrimes(int maxPrime)
   {
      Array values = Array.CreateInstance(typeof(int), 
                              new int[] { maxPrime - 1}, new int[] { 2 }); 
      // Use Sieve of Erathsthenes to determine prime numbers.
      for (int ctr = values.GetLowerBound(0); ctr <= (int) Math.Ceiling(Math.Sqrt(values.GetUpperBound(0))); ctr++)
      {
                           
         if ((int) values.GetValue(ctr) == 1) continue;
         
         for (int multiplier = ctr; multiplier <=  maxPrime / 2; multiplier++)
            if (ctr * multiplier <= maxPrime)
               values.SetValue(1, ctr * multiplier);
      }      
      
      List<String> primes = new List<String>();
      for (int ctr = values.GetLowerBound(0); ctr <= values.GetUpperBound(0); ctr++)
         if ((int) values.GetValue(ctr) == 0) 
            primes.Add(ctr.ToString() + " ");
      return primes;
   }   
}
// The example displays the following output:
//    Primes less than 100:
//       2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97

open System

let getPrimes maxPrime =
    let values = Array.CreateInstance(typeof<int>, [| maxPrime - 1|], [| 2 |]) 
    // Use Sieve of Erathsthenes to determine prime numbers.
    for i = values.GetLowerBound 0 to values.GetUpperBound 0 |> float |> sqrt |> ceil |> int do
        if values.GetValue i :?> int <> 1 then
            for multiplier = i to maxPrime / 2 do
                if i * multiplier <= maxPrime then
                    values.SetValue(1, i * multiplier)
    seq {
        for i = values.GetLowerBound 0 to values.GetUpperBound 0 do
            if values.GetValue i :?> int = 0 then
                string i + " "
    }    

let maxPrime = 100
let primeList = getPrimes maxPrime
printfn $"Primes less than {maxPrime}:"
printfn $"   {String.Concat primeList}"

// The example displays the following output:
//    Primes less than 100:
//       2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97

Imports System.Collections.Generic

Module Example
   Public Sub Main()
      Dim maxPrime As Integer = 100
      Dim primeList As IEnumerable(Of String) = GetPrimes(maxPrime)
      Console.WriteLine("Primes less than {0}:", maxPrime)
      Console.WriteLine("   {0}", String.Concat(primeList))
   End Sub
   
   Private Function GetPrimes(maxPrime As Integer) As IEnumerable(Of String)
      Dim values As Array = Array.CreateInstance(GetType(Integer), _
                              New Integer() { maxPrime - 1}, New Integer(){ 2 }) 
      ' Use Sieve of Erathsthenes to determine prime numbers.
      For ctr As Integer = values.GetLowerBound(0) To _
                           CInt(Math.Ceiling(Math.Sqrt(values.GetUpperBound(0))))
         If CInt(values.GetValue(ctr)) = 1 Then Continue For
         
         For multiplier As Integer = ctr To maxPrime \ 2
            If ctr * multiplier <= maxPrime Then values.SetValue(1, ctr * multiplier)
         Next   
      Next      
      
      Dim primes As New List(Of String)
      For ctr As Integer = values.GetLowerBound(0) To values.GetUpperBound(0)
         If CInt(values.GetValue(ctr)) = 0 Then primes.Add(ctr.ToString() + " ")
      Next            
      Return primes
   End Function   
End Module
' The example displays the following output:
'    Primes less than 100:
'       2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97

注解

该方法连接每个 values对象;它不添加任何分隔符。 若要指定每个成员 values之间的分隔符，请调用该方法 Join(String, IEnumerable<String>) 。

Empty字符串用于代替任何 null 元素。values

如果 values 为空 IEnumerable(Of String)，则该方法返回 String.Empty。 null如果是values，该方法将引发异常ArgumentNullException。

Concat(IEnumerable<String>) 是一种方便的方法，可用于连接集合中的每个元素， IEnumerable(Of String) 而无需先将元素转换为字符串数组。 它特别适用于 Language-Integrated 查询（LINQ）查询表达式。 以下示例将包含字母大写或小写字母的对象传递给 List(Of String) lambda 表达式，该表达式选择等于或大于特定字母的字母（在本示例中为“M”）。 IEnumerable(Of String)该方法返回Enumerable.Where的集合将传递给Concat(IEnumerable<String>)方法，以将结果显示为单个字符串。

using System;
using System.Collections.Generic;
using System.Linq;

public class Example
{
   public static void Main()
   {
      string output = String.Concat( GetAlphabet(true).Where( letter => 
                      letter.CompareTo("M") >= 0));
      Console.WriteLine(output);  
   }

   private static List<string> GetAlphabet(bool upper)
   {
      List<string> alphabet = new List<string>();
      int charValue = upper ? 65 : 97;
      for (int ctr = 0; ctr <= 25; ctr++)
         alphabet.Add(((char)(charValue + ctr)).ToString());
      return alphabet; 
   }
}
// The example displays the following output:
//      MNOPQRSTUVWXYZ

// This example uses the F# Seq.filter function instead of Linq.
open System

let getAlphabet upper =
    let charValue = if upper then 65 else 97
    seq {
        for i = 0 to 25 do
            charValue + i |> char |> string
    }

getAlphabet true
|> Seq.filter (fun letter -> letter.CompareTo "M" >= 0)
|> String.Concat
|> printfn "%s"
// The example displays the following output:
//      MNOPQRSTUVWXYZ

Imports System.Collections.Generic
Imports System.Linq

Module modMain
   Public Sub Main()
      Dim output As String = String.Concat(GetAlphabet(true).Where(Function(letter) _
                                                         letter >= "M"))
        
      Console.WriteLine(output)                                     
   End Sub
   
   Private Function GetAlphabet(upper As Boolean) As List(Of String)
      Dim alphabet As New List(Of String)
      Dim charValue As Integer = CInt(IIf(upper, 65, 97))
      For ctr As Integer = 0 To 25
         alphabet.Add(ChrW(charValue + ctr).ToString())
      Next
      Return alphabet 
   End Function
End Module
' The example displays the following output:
'       MNOPQRSTUVWXYZ

Concat(ReadOnlySpan<Char>, ReadOnlySpan<Char>)

Source:

String.Manipulation.cs

连接两个指定的只读字符范围的字符串表示形式。

public:
 static System::String ^ Concat(ReadOnlySpan<char> str0, ReadOnlySpan<char> str1);

public static string Concat(ReadOnlySpan<char> str0, ReadOnlySpan<char> str1);

static member Concat : ReadOnlySpan<char> * ReadOnlySpan<char> -> string

Public Shared Function Concat (str0 As ReadOnlySpan(Of Char), str1 As ReadOnlySpan(Of Char)) As String

参数

str0

ReadOnlySpan<Char>

要连接的第一个只读字符范围。

str1

ReadOnlySpan<Char>

要连接的第二个只读字符范围。

返回

String

值 str0 和 str1. 的串联字符串表示形式。

Concat<T>(IEnumerable<T>)

Source:

String.Manipulation.cs

连接实现的成员 IEnumerable<T> 。

public:
generic <typename T>
 static System::String ^ Concat(System::Collections::Generic::IEnumerable<T> ^ values);

public static string Concat<T>(System.Collections.Generic.IEnumerable<T> values);

static member Concat : seq<'T> -> string

Public Shared Function Concat(Of T) (values As IEnumerable(Of T)) As String

类型参数

T

成员 values的类型。

参数

values

IEnumerable<T>

实现接口的 IEnumerable<T> 集合对象。

返回

String

中的串联成员 values。

例外

ArgumentNullException

values 是 null。

示例

下面的示例定义一个非常简单的 Animal 类，该类包含动物的名称及其所属的顺序。 然后，它定义一个 List<T> 对象以包含多个 Animal 对象。 调用 Enumerable.Where 扩展方法以提取 Animal 其 Order 属性等于“Rodent”的对象。 结果将 Concat<T>(IEnumerable<T>) 传递给方法并显示给控制台。

using System;
using System.Collections.Generic;
using System.Linq;

public class Animal
{
   public string Kind;
   public string Order;
   
   public Animal(string kind, string order)
   {
      this.Kind = kind;
      this.Order = order;
   }
   
   public override string ToString()
   {
      return this.Kind;
   }
}

public class Example
{
   public static void Main()
   {
      List<Animal> animals = new List<Animal>();
      animals.Add(new Animal("Squirrel", "Rodent"));
      animals.Add(new Animal("Gray Wolf", "Carnivora"));
      animals.Add(new Animal("Capybara", "Rodent"));
      string output = String.Concat(animals.Where( animal => 
                      (animal.Order == "Rodent")));
      Console.WriteLine(output);  
   }
}
// The example displays the following output:
//      SquirrelCapybara

// This example uses the F# Seq.filter function instead of Linq.
open System

type Animal =
  { Kind: string
    Order: string }
    override this.ToString() =
       this.Kind

let animals = ResizeArray()
animals.Add { Kind = "Squirrel"; Order = "Rodent" }
animals.Add { Kind = "Gray Wolf"; Order = "Carnivora" }
animals.Add { Kind = "Capybara"; Order = "Rodent" }

Seq.filter (fun animal -> animal.Order = "Rodent")
|> String.Concat
|> printfn "%s"
// The example displays the following output:
//      SquirrelCapybara

Imports System.Collections.Generic

Public Class Animal
   Public Kind As String
   Public Order As String
   
   Public Sub New(kind As String, order As String)
      Me.Kind = kind
      Me.Order = order
   End Sub
   
   Public Overrides Function ToString() As String
      Return Me.Kind
   End Function
End Class

Module Example
   Public Sub Main()
      Dim animals As New List(Of Animal)
      animals.Add(New Animal("Squirrel", "Rodent"))
      animals.Add(New Animal("Gray Wolf", "Carnivora"))
      animals.Add(New Animal("Capybara", "Rodent")) 
      Dim output As String = String.Concat(animals.Where(Function(animal) _
                                           animal.Order = "Rodent"))
      Console.WriteLine(output)                                           
   End Sub
End Module
' The example displays the following output:
'      SquirrelCapybara

注解

该方法连接每个 values对象;它不添加任何分隔符。

Empty字符串用于代替任何 null 参数。

Concat<T>(IEnumerable<T>) 是一种方便的方法，可用于连接集合中的每个 IEnumerable<T> 元素，而无需先将元素转换为字符串。 如示例所示，它特别适用于 Language-Integrated 查询表达式（LINQ）查询表达式。 集合中 IEnumerable<T> 每个对象的字符串表示形式通过调用该对象的 ToString 方法派生。