.NET Framework Class Library
String.Join Method (String, String[])

Concatenates a specified separator String between each element of a specified String array, yielding a single concatenated string.

Namespace: System
Assembly: mscorlib (in mscorlib.dll)

Syntax

Visual Basic (Declaration)
Public Shared Function Join ( _
    separator As String, _
    value As String() _
) As String
Visual Basic (Usage)
Dim separator As String
Dim value As String()
Dim returnValue As String

returnValue = String.Join(separator, value)
C#
public static string Join (
    string separator,
    string[] value
)
C++
public:
static String^ Join (
    String^ separator, 
    array<String^>^ value
)
J#
public static String Join (
    String separator, 
    String[] value
)
JScript
public static function Join (
    separator : String, 
    value : String[]
) : String

Parameters

separator

A String.

value

An array of String.

Return Value

A String consisting of the elements of value interspersed with the separator string.
Exceptions

Exception typeCondition

ArgumentNullException

value is a null reference (Nothing in Visual Basic).

Remarks

For example if separator is ", " and the elements of value are "apple", "orange", "grape", and "pear", Join(separator, value) returns "apple, orange, grape, pear".

If separator is a null reference (Nothing in Visual Basic), the empty string (Empty) is used instead.

Example

The following code example demonstrates the Join method.

Visual Basic
Imports System

Public Class JoinTest
    
    Public Shared Sub Main()
        
        Console.WriteLine(MakeLine(0, 5, ", "))
        Console.WriteLine(MakeLine(1, 6, "  "))
        Console.WriteLine(MakeLine(9, 9, ": "))
        Console.WriteLine(MakeLine(4, 7, "< "))
    End Sub 'Main
    
    
    Private Shared Function MakeLine(initVal As Integer, multVal As Integer, sep As String) As String
        Dim sArr(10) As String
        Dim i As Integer
        
        
        For i = initVal To (initVal + 10) - 1
            sArr((i - initVal)) = [String].Format("{0,-3}", i * multVal)
        
        Next i
        Return [String].Join(sep, sArr)
    End Function 'MakeLine
End Class 'JoinTest
C#
using System;

public class JoinTest {
    public static void Main() {

        Console.WriteLine(MakeLine(0, 5, ", "));
        Console.WriteLine(MakeLine(1, 6, "  "));
        Console.WriteLine(MakeLine(9, 9, ": "));
        Console.WriteLine(MakeLine(4, 7, "< "));
    }

    private static string MakeLine(int initVal, int multVal, string sep) {

        string [] sArr = new string [10];

        for (int i = initVal; i < initVal + 10; i++)
            sArr[i - initVal] = String.Format("{0,-3}", i * multVal);

        return String.Join(sep, sArr);
    }
}
C++
using namespace System;
String^ MakeLine( int initVal, int multVal, String^ sep )
{
   array<String^>^sArr = gcnew array<String^>(10);
   for ( int i = initVal; i < initVal + 10; i++ )
      sArr[ i - initVal ] = String::Format( "{0, -3}", i * multVal );
   return String::Join( sep, sArr );
}

int main()
{
   Console::WriteLine( MakeLine( 0, 5, ", " ) );
   Console::WriteLine( MakeLine( 1, 6, "  " ) );
   Console::WriteLine( MakeLine( 9, 9, ": " ) );
   Console::WriteLine( MakeLine( 4, 7, "< " ) );
}
J#
import System.*;

public class JoinTest
{
    public static void main(String[] args)
    {
        Console.WriteLine(MakeLine(0, 5, ", "));
        Console.WriteLine(MakeLine(1, 6, "  "));
        Console.WriteLine(MakeLine(9, 9, ": "));
        Console.WriteLine(MakeLine(4, 7, "< "));
    } //main

    private static String MakeLine(int initVal, int multVal, String sep)
    {
        String sArr[] = new String[10];

        for (int i = initVal; i < initVal + 10; i++) {
            sArr.set_Item((i - initVal), String.Format("{0,-3}", 
                (Int32)(i * multVal)));
        }
        return String.Join(sep, sArr);
    } //MakeLine
} //JoinTest
JScript
import System;

public class JoinTest {
    public static function Main() : void {
        Console.WriteLine(MakeLine(0, 5, ", "));
        Console.WriteLine(MakeLine(1, 6, "  "));
        Console.WriteLine(MakeLine(9, 9, ": "));
        Console.WriteLine(MakeLine(4, 7, "< "));
    }

    private static function MakeLine(initVal : int, multVal : int, sep : String) : String  {

        var sArr : String [] = new String [10];

        for (var i : int = initVal; i < initVal + 10; i++)
            sArr[i - initVal] = String.Format("{0,-3}", i * multVal);

        return String.Join(sep, sArr);
    }
}
JoinTest.Main();
Platforms

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

Version Information

.NET Framework

Supported in: 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0
See Also

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