Environment.GetEnvironmentVariable Method (String) (System)

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.NET Framework Class Library
Environment.GetEnvironmentVariable Method (String)

Retrieves the value of an environment variable from the current process.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)
Syntax
Visual Basic
Public Shared Function GetEnvironmentVariable ( _
	variable As String _
) As String
C#
public static string GetEnvironmentVariable(
	string variable
)
Visual C++
public:
static String^ GetEnvironmentVariable(
	String^ variable
)
F#
static member GetEnvironmentVariable : 
        variable:string -> string

Parameters

variable
Type: System.String
The name of the environment variable.

Return Value

Type: System.String
The value of the environment variable specified by variable, or null if the environment variable is not found.
Exceptions
Exception Condition
ArgumentNullException

variable is null.
SecurityException

The caller does not have the required permission to perform this operation.
Remarks

Environment variable names are not case-sensitive.

Examples

The following example demonstrates the GetEnvironmentVariable method.

Visual Basic

' Change the directory to %WINDIR%							
Environment.CurrentDirectory = Environment.GetEnvironmentVariable("windir")
Dim info As New DirectoryInfo(".")
Console.WriteLine(("Directory Info:   " + info.FullName))
C#

		// Change the directory to %WINDIR%							
		Environment.CurrentDirectory = Environment.GetEnvironmentVariable("windir");		
		DirectoryInfo info = new DirectoryInfo(".");
        	lock(info)
        	{      
			Console.WriteLine("Directory Info:   "+info.FullName);
        	}
Visual C++

// Change the directory to %WINDIR%       
Environment::CurrentDirectory = Environment::GetEnvironmentVariable( "windir" );
DirectoryInfo^ info = gcnew DirectoryInfo( "." );
System::Threading::Monitor::Enter( info );
try
{
   Console::WriteLine( "Directory Info:   {0}", info->FullName );
}
finally
{
   System::Threading::Monitor::Exit( info );
}
Version Information

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1
.NET Framework Security
Platforms

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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

Reference

Environment Class
GetEnvironmentVariable Overload
System Namespace
GetEnvironmentVariables
SetEnvironmentVariable