Null value for HINSTANCE

[fernandanavamoya]

Is your feature request related to a problem? Please describe.
Inside a method that returns a HINSTANCE, the returning null value has to be explicitly cast to an HINSTANCE: (HINSTANCE)0 .

public unsafe static HINSTANCE LoadLibraryFromSystemPathIfAvailable(string libraryName)
{
   if (GetModuleHandle(Libraries.Kernel32) == 0)
   {
       return (HINSTANCE)0;
   }

    // LOAD_LIBRARY_SEARCH_SYSTEM32 was introduced in KB2533623. Check for its presence
    // to preserve compat with Windows 7 SP1 without this patch.
    fixed (char* lpLibFileName = libraryName)
    {
        HINSTANCE result = LoadLibraryEx(lpLibFileName, (HANDLE)0, LOAD_LIBRARY_FLAGS.LOAD_LIBRARY_SEARCH_SYSTEM32);
        if (result != 0)
        {
             return result;
        }

        // Load without this flag.
        if (Marshal.GetLastWin32Error() != ERROR.INVALID_PARAMETER)
        {
             return (HINSTANCE)0;
        }

        return LoadLibraryEx(lpLibFileName, (HANDLE)0, 0);
    }
}

Describe the solution you'd like
A null value for HINSTANCE, such as:

HINSTANCE.Null

[JeremyKuhne]

In general this would be nice for the wrapper structs (HWND, HDC, etc.).

[elachlan]

Maybe we can add it along side #610?

[elachlan]

So pretty much:

public static readonly IntPtr Null;

[jnm2]

Wouldn't this be:

public static readonly HINSTANCE Null;

[elachlan]

Yes. I realised this as I went to bed. I'll fix it.