String.Concat 方法

定义

连接 String 的一个或多个实例,或 String 的一个或多个实例的值的 Object 表示形式。

重载

Concat(IEnumerable<String>)

串联类型为 IEnumerable<T>String 构造集合的成员。

Concat(String, String, String, String)

连接 String 的四个指定实例。

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 String 的三个指定实例。

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(Object, Object, Object, Object)

将四个指定对象的字符串表示形式与可选变量长度参数列表中指定的任何对象串联起来。

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(Object, Object)

连接两个指定对象的字符串表示形式。

Concat(String[])

连接指定的 String 数组的元素。

Concat(Object[])

连接指定 Object 数组中的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(String, String)

连接 String 的两个指定实例。

Concat<T>(IEnumerable<T>)

串联 IEnumerable<T> 实现的成员。

注解

备注

你还可以使用语言的字符串串联运算符(如 + c # 中的), &+ 在 Visual Basic 中连接字符串。 这两个编译器都将串连运算符转换为对的重载之一的调用 String.Concat

Concat(IEnumerable<String>)

串联类型为 IEnumerable<T>String 构造集合的成员。

public:
 static System::String ^ Concat(System::Collections::Generic::IEnumerable<System::String ^> ^ values);
public static string Concat (System.Collections.Generic.IEnumerable<string> values);
public static string Concat (System.Collections.Generic.IEnumerable<string?> values);
[System.Runtime.InteropServices.ComVisible(false)]
public static string Concat (System.Collections.Generic.IEnumerable<string> values);
static member Concat : seq<string> -> string
[<System.Runtime.InteropServices.ComVisible(false)>]
static member Concat : seq<string> -> string
Public Shared Function Concat (values As IEnumerable(Of String)) As String

参数

values
IEnumerable<String>

一个集合对象,该对象实现 IEnumerable<T>,且其泛型类型参数为 String

返回

String

values 中的串联字符串;如果 values 为空 IEnumerable(Of String),则为 Empty

属性

例外

values 上声明的默认值为 null

示例

下面的示例使用埃拉托色 of 尼斯筛法算法来计算小于或等于100的质数。 它将结果分配给 List<T> 类型的对象,然后将该对象 String 传递给 Concat(IEnumerable<String>) 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
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

此方法连接中的每个对象 values ; 它不添加任何分隔符。 若要指定每个成员之间的分隔符 values ,请调用 Join(String, IEnumerable<String>) 方法。

Empty字符串用于替换中的任何 null 元素 values

如果 values ,则为 IEnumerable(Of String),则此方法返回 String.Empty。 如果 valuesnull ,则该方法将引发 ArgumentNullException 异常。

Concat(IEnumerable<String>) 是一种简便方法,使您可以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。 它对于 Language-Integrated 查询 (LINQ) 查询表达式特别有用。 下面的示例将 List(Of String) 包含字母表的大写或小写字母的对象传递给 lambda 表达式,该表达式选择等于或大于特定字母 (的字母,在本例中为 "M" ) 。 IEnumerable(Of String)方法返回的集合 Enumerable.Where 传递给 Concat(IEnumerable<String>) 方法,以单个字符串的形式显示结果。

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
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

适用于

Concat(String, String, String, String)

连接 String 的四个指定实例。

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);
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

要串联的第一个字符串。

str1
String

要串联的第二个字符串。

str2
String

要比较的第三个字符串。

str3
String

要比较的第四个字符串。

返回

String

str0str1str2str3 的串联。

示例

下面的示例定义一个包含四个字母的单词数组,并存储其单个字母到字符串数组中,以便将它们进行排列。 然后,它 Concat(String, String, String, String) 调用 方法来重新组合已重装的单词。

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
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

方法连接 str0 str1 、、 和 str2 str3 ;它不会添加任何分隔符。

另请参阅

适用于

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。

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

str0str1str2str3 的值的已连接字符串表示形式。

适用于

Concat(String, String, String)

连接 String 的三个指定实例。

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

要串联的第一个字符串。

str1
String

要串联的第二个字符串。

str2
String

要比较的第三个字符串。

返回

String

str0str1str2 的串联。

示例

下面的示例使用 Concat 方法连接三个字符串并显示结果。

using namespace System;

void main()
{
   String^ s1 = "We went to a bookstore, ";
   String^ s2 = "a movie, ";
   String^ s3 = "and a restaurant.";

   String^ 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.
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.
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

方法连接 str0 、和,而 str1 str2 不添加任何分隔符。

另请参阅

适用于

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。

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

str0str1str2 的值的已连接字符串表示形式。

适用于

Concat(Object, Object, Object)

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);
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

arg0arg1arg2 的值的串联字符串表示形式。

示例

下面的示例演示 Concat 方法。

using namespace System;

int main()
{
   int i = -123;
   Object^ o = i;
   array<Object^>^objs = { -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
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
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

方法 arg0 arg1 arg2 通过调用每个对象的无参数方法连接、和,而 ToString 不添加任何分隔符。

String.Empty 用于替代任何空参数。

另请参阅

适用于

Concat(Object, Object, Object, Object)

重要

此 API 不符合 CLS。

将四个指定对象的字符串表示形式与可选变量长度参数列表中指定的任何对象串联起来。

public:
 static System::String ^ Concat(System::Object ^ arg0, System::Object ^ arg1, System::Object ^ arg2, System::Object ^ arg3);
[System.CLSCompliant(false)]
public static string Concat (object arg0, object arg1, object arg2, object arg3);
[<System.CLSCompliant(false)>]
static member Concat : obj * obj * obj * obj -> string
Public Shared Function Concat (arg0 As Object, arg1 As Object, arg2 As Object, arg3 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。

arg3
Object

要连接的第四个对象。

返回

String

参数列表中的每个值的连接字符串表示形式。

属性

示例

下面的示例演示如何使用 方法来连接变量参数 Concat(Object, Object, Object, Object) 的列表。 在这种情况下,使用九个参数调用 方法。

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
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

备注

此 API 不符合 CLS。 符合 CLS 的替代方法是 String.Concat(Object[])。 c # 和 Visual Basic 编译器会自动将对此方法的调用解析为对的调用 String.Concat(Object[])

方法通过调用其无参数方法连接参数列表中的每个对象,而不 ToString 会添加任何分隔符。

String.Empty 用于替代任何空参数。

备注

方法的最后一个参数 Concat 是要连接的一个或多个附加对象的以逗号分隔的可选列表。

调用方说明

此方法使用 关键字 vararg 进行标记,这意味着它支持可变数量的参数。 方法可以从 Visual C++ 调用,但不能从 C# 或 Visual Basic调用。 C# 和 Visual Basic编译器将 对 的调用 Concat(Object, Object, Object, Object) 解析为对 的调用 Concat(Object[])

适用于

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。

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

str0str1 的值的串联字符串表示形式。

适用于

Concat(Object, Object)

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);
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

arg0arg1 的值的串联字符串表示形式。

示例

下面的示例演示 Concat 方法。

using namespace System;

int main()
{
   int i = -123;
   Object^ o = i;
   array<Object^>^objs = { -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
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
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

方法 arg0 arg1 通过调用和的无参数方法连接和,而 ToString arg0 arg1 不添加任何分隔符。

String.Empty 用于替代任何空参数。

如果任何一个参数为数组引用,则该方法将连接一个表示该数组的字符串,而不是它的成员 (例如 "System.string []" ) 。

另请参阅

适用于

Concat(String[])

重要

此 API 不符合 CLS。

连接指定的 String 数组的元素。

public:
 static System::String ^ Concat(... cli::array <System::String ^> ^ values);
public static string Concat (params string[] values);
public static string Concat (params string?[] values);
[System.CLSCompliant(false)]
public static string Concat (params string[] values);
static member Concat : string[] -> string
[<System.CLSCompliant(false)>]
static member Concat : string[] -> string
Public Shared Function Concat (ParamArray values As String()) As String

参数

values
String[]

字符串实例的数组。

返回

String

values 的串联元素。

属性

例外

values 上声明的默认值为 null

内存不足。

示例

下面的示例演示如何将方法用于 Concat String 数组。

using namespace System;

int main()
{
   
   // Make an array of strings. Note that we have included spaces.
   array<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
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
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

此方法连接中的每个对象 values ; 它不添加任何分隔符。

Empty字符串用于替代数组中的任何 null 对象。

另请参阅

适用于

Concat(Object[])

连接指定 Object 数组中的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);
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

args 中元素的值的串联字符串表示形式。

例外

args 上声明的默认值为 null

内存不足。

示例

下面的示例演示如何将方法用于 Concat Object 数组。

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
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

方法 args 通过调用该对象的无参数方法来连接中的每个对象,而不 ToString 会添加任何分隔符。

String.Empty 用于替代数组中的任何 null 对象。

调用方说明

C + + 代码不会调用此方法。 C + + 编译器解析对 Concat 的调用,该调用具有四个或更多对象参数作为对的调用 Concat(Object, Object, Object, Object)

另请参阅

适用于

Concat(Object)

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);
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

arg0 的值的字符串表示形式,如果 Emptyarg0,则为 null

示例

下面的示例演示 Concat 方法。

using namespace System;

int main()
{
   int i = -123;
   Object^ o = i;
   array<Object^>^objs = { -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
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
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

Concat(Object)方法 arg0 通过调用其无参数的方法将表示为字符串 ToString

另请参阅

适用于

Concat(String, String)

连接 String 的两个指定实例。

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

要串联的第一个字符串。

str1
String

要串联的第二个字符串。

返回

String

str0str1 的串联。

示例

下面的示例将用户的名字、中间名和姓氏连接起来。

using namespace System;
int 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 = String::Concat(  " ", mName->Trim() );
   lName = String::Concat(  " ", 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'!
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'!
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

方法连接 str0str1 ; 它不添加任何分隔符。

Empty字符串用于替代任何空参数。

另请参阅

适用于

Concat<T>(IEnumerable<T>)

串联 IEnumerable<T> 实现的成员。

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);
[System.Runtime.InteropServices.ComVisible(false)]
public static string Concat<T> (System.Collections.Generic.IEnumerable<T> values);
static member Concat : seq<'T> -> string
[<System.Runtime.InteropServices.ComVisible(false)>]
static member Concat : seq<'T> -> string
Public Shared Function Concat(Of T) (values As IEnumerable(Of T)) As String

类型参数

T

values 成员的类型。

参数

values
IEnumerable<T>

一个实现 IEnumerable<T> 接口的集合对象。

返回

String

values 中的串联成员。

属性

例外

values 上声明的默认值为 null

示例

下面的示例定义了一个非常简单的类,该类包含动物的名称及其 Animal 所属顺序。 然后,它 List<T> 定义一个 对象以包含多个 Animal 对象。 调用 Enumerable.Where 扩展方法以提取 Animal 其属性等于 Order "Rodent"的对象。 结果将传递给 Concat<T>(IEnumerable<T>) 方法并显示到控制台。

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
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

方法连接 中的每个对象 values ;它不会添加任何分隔符。

Empty字符串用于表示任何 null 参数。

Concat<T>(IEnumerable<T>) 是一种便捷方法,可用于连接集合中每个元素,而无需 IEnumerable<T> 先将元素转换为字符串。 如示例所示,Language-Integrated查询 (LINQ) 查询表达式特别有用。 集合中每个对象的字符串表示形式通过调用该对象的 方法 IEnumerable<T> 派生 ToString

适用于