[FIXED] C++ DirectX rendering of a C# Canvas

Hey folks,

So as the title suggests I'm trying to handle the rendering of a C# Panel instance (in this case a Canvas) using C++ and DirectX - but I'm having trouble creating the device and swap chain instance on the C++ side of things.

The C# application has 'Canvas' instance in the XAML (I've also tried a Windows.Forms panel, as shown below):

<Grid Grid.Row="0">
    <!-- <WindowsFormsHost Width="800" Height="600" x:Name="myEngineWindow">
        <wf:Panel Width="800" Height="600" x:Name="myDXControl"/>
    </WindowsFormsHost> -->
    <Canvas Width="800" Height="600" x:Name="myDXControl" />
</Grid>

And in my application's 'Loaded' event callback I grad the window handle from the Canvas and send it through to my C++ renderer (SoundSynthesisInterface):

HwndSource hwndSource = (HwndSource)HwndSource.FromVisual(myDXControl);
SoundSynthesisInterface.Instance.InitializeEngine(hwndSource.Handle, (int)myDXControl.Width, (int)myDXControl.Height); 

The SoundSynthesisInterface is a managed C++ class, and converts the IntPtr supplied by C# to a HWND instance, and then uses that window handle to try and initialize the device context and swap chain:

bool SoundSynthesisInterface::InitializeEngine( IntPtr aWindowHandle, int aWindowWidth, int aWindowHeight )
{
  ...
  HWND windowHandle = (HWND)aWindowHandle.ToPointer();

  ...

  InitializeRenderContext(windowHandle, aWindowWidth, aWindowHeight);
} 

The HWND instance that gets passed through to InitializeRenderContext is non-null, but when I call the following code to create the device & swap chain:

 // create a structure to hold information about the swap chain
 DXGI_SWAP_CHAIN_DESC swapChainDescription;
 ZeroMemory( &swapChainDescription, sizeof(DXGI_SWAP_CHAIN_DESC) );

 HRESULT result = S_OK;

 // fill in the swap chain structure
 swapChainDescription.BufferCount        = 2;
 swapChainDescription.BufferDesc.Format  = DXGI_FORMAT_R8G8B8A8_UNORM;
 swapChainDescription.BufferUsage        = DXGI_USAGE_RENDER_TARGET_OUTPUT;
 swapChainDescription.OutputWindow       = windowHandle;
 swapChainDescription.SampleDesc.Count   = 8;
 swapChainDescription.SampleDesc.Quality = 1;
 swapChainDescription.Windowed           = TRUE;
 swapChainDescription.Flags              = DXGI_SWAP_CHAIN_FLAG_ALLOW_MODE_SWITCH;

 // create the context
 result = D3D11CreateDeviceAndSwapChain(
     NULL,
     D3D_DRIVER_TYPE_HARDWARE,
     NULL,
     NULL,
     NULL,
     NULL,
     D3D11_SDK_VERSION,
     &swapChainDescription,
     &m_swapChain,
     &m_device,
     NULL,
     &m_deviceContext
 ); 

I get the following error code:

    0x80070057

Which I think means that one of the parameters I'm passing in to CreateDeviceAndSwapChain is invalid... but I'm not sure what I'm doing wrong here. Anyone have any bright ideas? m_swapChain, m_device & m_deviceContext are all initialized to 'nullptr' by the class constructor.

I'm currently running on Windows 7 with VS2015 and I'm linking to the 'Windows Kit v8.1' version of the DXSDK. Both the C# and C++ projects are complied using an x64 configuration, as are all DirectX libs I'm linking to.

Thanks for the help!