String::Join Method (String, array<String>, Int32, Int32)

Updated: January 2011

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)

public:
static String^ Join(
	String^ separator, 
	array<String^>^ value, 
	int startIndex, 
	int count
)

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.

ExceptionCondition
ArgumentNullException

value is nullptr.

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.

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 nullptr, an empty string is used instead. If any element in value is nullptr, an empty string is used instead.

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

// 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'
*/

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.

.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

Date

History

Reason

January 2011

Noted that an empty string is substituted for any null element in the array.

Customer feedback.

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