Check OS best practice

Question

Hello
To check the OS version and terminate the app if OS is older than XP (in .NET framework 4.0):

If Not Version.op_GreaterThanOrEqual(Environment.OSVersion.Version, New Version(5, 1, 0, 0)) Then...

I've seen that should not use Environment, which method you guys recommend?

** I mean a more reliable method to detect OS version in .net 4.0

** In .NET versions prior to .NET 5, Environment.OSVersion returns an OS version that may be incorrect when an application runs under Windows compatibility mode

Answer 1

The method used by MS up to Windows 10 is RtlGetVersion
(then comparing Major/Minor from Operating System Version)
(on Windows 11, APIs from Winbrand.dll)

A test :

        Dim ovi As RTL_OSVERSIONINFOW = New RTL_OSVERSIONINFOW With {  
            .dwOSVersionInfoSize = Marshal.SizeOf(GetType(RTL_OSVERSIONINFOW))  
        }  
        Dim ntStatus As UInteger = RtlGetVersion(ovi)  
        Console.WriteLine("Major version : {0} - Minor version : {1} - Build Number : {2}", ovi.dwMajorVersion.ToString(),  
                          ovi.dwMinorVersion.ToString(), ovi.dwBuildNumber.ToString())  

with :

    <DllImport("Ntdll.dll", SetLastError:=True, CharSet:=CharSet.Unicode)>  
    Public Shared Function RtlGetVersion(ByRef lpVersionInformation As RTL_OSVERSIONINFOW) As UInteger  
    End Function  
  
    <StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Unicode)>  
    Public Structure RTL_OSVERSIONINFOW  
        Public dwOSVersionInfoSize As UInteger  
        Public dwMajorVersion As UInteger  
        Public dwMinorVersion As UInteger  
        Public dwBuildNumber As UInteger  
        Public dwPlatformId As UInteger  
        <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=128)>  
        Public szCSDVersion As String  
    End Structure  

Answer 2

............ following the 'Then', maybe the keyword 'End' is what you are looking for - maybe not.

Answer 3

There is nothing wrong with using Environment.OSVersion.Version to check for a pre-XP OS.

But I think this is a mute point because if your app is targeting .NET 4 then the earliest OS you can install the framework on is XP if I remember correctly. Without the framework your app won't run. Hence you cannot run your app on a version of the OS prior to XP anyway so this shouldn't be a scenario you need to worry about.