private static unsafe Icon ExtractAssociatedIcon(string filePath, int index)
{
if (filePath == null)
{
throw new ArgumentNullException(nameof(filePath));
}
filePath = Path.GetFullPath(filePath);
if (!File.Exists(filePath))
{
throw new FileNotFoundException(message: null, fileName: filePath);
}
// ExtractAssociatedIcon copies the loaded path into the buffer that it is passed.
// It isn't clear what the exact semantics are for copying back the path, a quick
// look at the code it might be hard coded to 128 chars for some cases. Leaving the
// historical MAX_PATH as a minimum to be safe.
char[] buffer = ArrayPool <char> .Shared.Rent(Math.Max(NativeMethods.MAX_PATH, filePath.Length));
filePath.CopyTo(0, buffer, 0, filePath.Length);
buffer[filePath.Length] = '\0';
fixed(char *b = buffer)
{
IntPtr hIcon = SafeNativeMethods.ExtractAssociatedIcon(NativeMethods.NullHandleRef, b, ref index);
ArrayPool <char> .Shared.Return(buffer);
if (hIcon != IntPtr.Zero)
{
return(new Icon(hIcon, true));
}
}
return(null);
}
