Question

I have some code that attempts to test whether my application is running with the themes set. Here s the C# code:

internal class NativeMethods
{

   [DllImport("comctl32", CharSet = CharSet.Auto, SetLastError = true)]
   internal static extern uint DllGetVersion(ref DLLVERSIONINFO pdvi);

   [StructLayout(LayoutKind.Sequential)]
   internal struct DLLVERSIONINFO
   {
    public uint cbSize;
    public uint dwMajorVersion;
    public uint dwMinorVersion;
    public uint dwBuildNumber;
    public uint dwPlatformID;
   }

            internal static bool IsThemed()
   {
    bool retval = false;

    if ((Environment.OSVersion.Version.Major >= 5 &&
      Environment.OSVersion.Version.Minor >= 1) ||
      Environment.OSVersion.Version.Major > 5)
    {
     bool appThemed = NativeMethods.IsAppThemed();
     bool themeActive = NativeMethods.IsThemeActive();

     if (appThemed && themeActive)
     {
      DLLVERSIONINFO dvi = new DLLVERSIONINFO();
      dvi.cbSize = (uint)Marshal.SizeOf(dvi);

      NativeMethods.DllGetVersion(ref dvi);

      retval = (dvi.dwMajorVersion >= 6);
     }
    }
}

This code works great for my needs under Windows XP, 2003 and Vista. However, when I try it under Windows 7, where I m running Aero, the call to DllGetVersion returns a value less than 6. When I debug my application and look at the version number of comctl32 under the debugger (modules window), it shows a version number greater than 6 is loaded. Why does my code return a different number?

Thanks,

Notre

Answer 1

Looking at MSDN for DllGetVersion(), it sounds like this might not be the best way to do what you re trying to do. Since this isn t an API function, it s possible that this changed in Win7 somehow and can t be called in the same way.

If you re using WinForms, you could try calling Application.RenderWithVisualStyles - that sounds like it s doing what you re trying to do above.

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