Environment.GetEnvironmentVariable Method (String) (System)

GetEnvironmentVariable Method (Stri...

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This page is specific to

Microsoft Visual Studio 2008/.NET Framework 3.5

Other versions are also available for the following:

.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 (Declaration)

Public Shared Function GetEnvironmentVariable ( _
    variable As String _
) As String

Visual Basic (Usage)

Dim variable As String
Dim returnValue As String

returnValue = Environment.GetEnvironmentVariable(variable)

public static string GetEnvironmentVariable(
    string variable
)

Visual C++

public:
static String^ GetEnvironmentVariable(
    String^ variable
)

JScript

public static function 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 nullNothingnullptra null reference (Nothing in Visual Basic) if the environment variable is not found.

Exceptions

Exception	Condition
ArgumentNullException	variable is nullNothingnullptra null reference (Nothing in Visual Basic).
SecurityException	The caller does not have the required permission to perform this operation.

Remarks

Environment variable names are not case-sensitive.

Examples

The following code 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))

        // 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 );
}

.NET Framework Security

EnvironmentPermission
for the ability to read the value of variable. Associated enumeration: EnvironmentPermissionAccess..::.Read

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

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

Reference

Environment Class

Environment Members

GetEnvironmentVariable Overload

System Namespace

GetEnvironmentVariables

SetEnvironmentVariable