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Interaction.Environ Method (Int32)

Returns the string associated with an operating-system environment variable.

Namespace:  Microsoft.VisualBasic
Assembly:  Microsoft.VisualBasic (in Microsoft.VisualBasic.dll)

public static string Environ(
	int Expression


Type: System.Int32

Required. Expression that evaluates either a string containing the name of an environment variable, or an integer corresponding to the numeric order of an environment string in the environment-string table.

Return Value

Type: System.String
Returns the string associated with an operating-system environment variable.

For more detailed information, see the Visual Basic topic Environ Function.

If Expression contains a string, the Environ function returns the text assigned to the specified environment string—that is, the text following the equal sign (=) in the environment-string table for that environment variable. If the string in Expression cannot be found in the environment-string table, a zero-length string ("") is returned.

If Expression contains an integer, the string occupying that numeric position in the environment-string table is returned. In this case, Environ returns all of the text, including the name of the environment variable. If there is no environment string in the specified position, Environ returns a zero-length string.

Security noteSecurity Note:

The Environ function requires environment permission, which might affect its execution in partial-trust situations. For more information, see SecurityPermission and Code Access Permissions.

This example uses the Environ function to supply the entry number and length of the PATH statement from the environment-string table.

Sub tenv()
   Dim envString As String 
   Dim found As Boolean = False 
   Dim index As Integer = 1
   Dim pathLength As Integer 
   Dim message As String

   envString = Environ(index)
   While Not found And (envString <> "")
      If (envString.Substring(0, 5) = "Path=") Then
         found = True 
         index += 1
         envString = Environ(index) 
      End If 
   End While 

   If found Then
      pathLength = Environ("PATH").Length
      message = "PATH entry = " & index & " and length = " & pathLength
      message = "No PATH environment variable exists." 
   End If

End Sub

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.

.NET Framework

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

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