.NET Framework Class Library
String..::.Join Method (String, array<String>[]()[], Int32, Int32)

Concatenates a specified separator String between each element of a specified String array, yielding a single concatenated string. Parameters specify the first array element and number of elements to use.

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

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

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

Parameters

separator
Type: System..::.String
A String.
value
Type: array<System..::.String>[]()[]
An array of String.
startIndex
Type: System..::.Int32
The first array element in value to use.
count
Type: System..::.Int32
The number of elements of value to use.

Return Value

Type: System..::.String
A String object consisting of the strings in value joined by separator. Or, Empty if count is zero, value has no elements, or separator and all the elements of value are Empty.
Exceptions

ExceptionCondition
ArgumentNullException

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

ArgumentOutOfRangeException

startIndex or count is less than 0.

-or-

startIndex plus count is greater than the number of elements in value.

OutOfMemoryException

Out of memory.

Remarks

For example if separator is ", " and the elements of value are "apple", "orange", "grape", and "pear", Join(separator, value, 1, 2) returns "orange, grape".

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

Examples

The following example concatenates two elements from an array of names of fruit.

Visual Basic
' Sample for String.Join(String, String[], int int)
Imports System
 _

Class Sample

   Public Shared Sub Main()
      Dim val As [String]() =  {"apple", "orange", "grape", "pear"}
      Dim sep As [String] = ", "
      Dim result As [String]

      Console.WriteLine("sep = '{0}'", sep)
      Console.WriteLine("val() = {{'{0}' '{1}' '{2}' '{3}'}}", val(0), val(1), val(2), val(3))
      result = [String].Join(sep, val, 1, 2)
      Console.WriteLine("String.Join(sep, val, 1, 2) = '{0}'", result)
   End Sub 'Main
End Class 'Sample
'
'This example produces the following results:
'sep = ', '
'val() = {'apple' 'orange' 'grape' 'pear'}
'String.Join(sep, val, 1, 2) = 'orange, grape'
'
C#
// Sample for String.Join(String, String[], int int)
using System;

class Sample {
    public static void Main() {
    String[] val = {"apple", "orange", "grape", "pear"};
    String sep   = ", ";
    String result;

    Console.WriteLine("sep = '{0}'", sep);
    Console.WriteLine("val[] = {{'{0}' '{1}' '{2}' '{3}'}}", val[0], val[1], val[2], val[3]);
    result = String.Join(sep, val, 1, 2);
    Console.WriteLine("String.Join(sep, val, 1, 2) = '{0}'", result);
    }
}
/*
This example produces the following results:
sep = ', '
val[] = {'apple' 'orange' 'grape' 'pear'}
String.Join(sep, val, 1, 2) = 'orange, grape'
*/
Visual C++
// Sample for String::Join(String, String[], int int)
using namespace System;
int main()
{
   array<String^>^val = {"apple","orange","grape","pear"};
   String^ sep = ", ";
   String^ result;
   Console::WriteLine( "sep = '{0}'", sep );
   Console::WriteLine( "val[] = {{'{0}' '{1}' '{2}' '{3}'}}", val[ 0 ], val[ 1 ], val[ 2 ], val[ 3 ] );
   result = String::Join( sep, val, 1, 2 );
   Console::WriteLine( "String::Join(sep, val, 1, 2) = '{0}'", result );
}

/*
This example produces the following results:
sep = ', '
val[] = {'apple' 'orange' 'grape' 'pear'}
String::Join(sep, val, 1, 2) = 'orange, grape'
*/
Platforms

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
Version Information

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 3.0, 2.0, 1.0
See Also

Reference

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