private void Dispose(bool disposing)
 {
     if (IsDisposed)
     {
         return;
     }
     _viewModel?.Dispose();
     _renderTarget?.Dispose();
     _renderTargetD3D9?.Dispose();
     _instanceCount--;
     if (_instanceCount <= 0)
     {
         _graphicsDeviceService?.Dispose();
     }
     IsDisposed = true;
 }