How to determine the operating system service pack level in Visual Basic .NET or in Visual Basic 2005 (304722)

MORE INFORMATION

The OSVersion property, which is provided for obtaining operating system (OS) information, does not contain a member that provides service pack information. To determine what service pack is installed, you must call the GetVersionEx API function directly. Typically, it is better to avoid this practice; the .NET Framework provides access to the underlying API sets in a much more consistent (and easier to use) manner than by calling the individual API functions.

When you must call an API function directly, you can do this through the Interop layer of the .NET Framework. The sample code in this article gives a method, GetServicePack, that returns the service pack level.

NOTE: The OSVERSIONINFO structure contains a fixed-length string, szCSDVersion. Because fixed-length strings are no longer supported, you must provide the marshalling information for this member. Do this by using the attribute (denoted by <>) preceding the member name.

1. Open a new Visual Basic .NET or Visual Basic 2005 console application.
2. Open the code window for Module1.vb, and delete all of the code.
3. Paste the following code into Module1.vb.

   Module module1
       Private Structure OSVERSIONINFO
           Dim dwOSVersionInfoSize As Integer
           Dim dwMajorVersion As Integer
           Dim dwMinorVersion As Integer
           Dim dwBuildNumber As Integer
           Dim dwPlatformId As Integer
           <VBFixedString(128), _
             System.Runtime.InteropServices.MarshalAs _
                  (System.Runtime.InteropServices.UnmanagedType.ByValTStr, _
               SizeConst:=128)> Dim szCSDVersion As String
   
       End Structure
   
       Private Declare Function GetVersionExA Lib "kernel32" (ByRef lpVersionInformation As OSVERSIONINFO) As Short
   
       Public Function getServicePack() As String
           Dim osinfo As OSVERSIONINFO
           Dim retvalue As Short
           osinfo.dwOSVersionInfoSize = 148
           retvalue = GetVersionExA(osinfo)
           If Len(osinfo.szCSDVersion) = 0 Then
               Return ("No Service Pack Installed")
           Else
               Return (CStr(osinfo.szCSDVersion))
           End If
       End Function
   
       Public Sub main()
           Console.WriteLine(getServicePack())
       End Sub
   End Module
   

4. Press CTRL+F5 to build and then run the project. The service pack information appears in the console window.