SharpDX Toolkit has support for WPF via a Direct3D11-to-Direct3D9 shared texture. It is implemented in the SharpDXElement class.
You may not be able to reuse this as is because Direct2D (which you are using to draw) can interop either with Direct3D11.1 or Direct3D10 and SharpDX uses Direct3D11 for WPF support, so you will need to tweak the solution a little bit.
Basically you need to do the following:
- Initialize Direct3D (10 or 11.1).
- Initialize Direct2D.
- Create the D3D render target with Direct2D support and the Shared flag (here is how it is done in SharpDX).
- Initialize Direct3D9.
- Create the shared texture.
- Bind the texture to an D3DImage.
Do not forget to call D3DImage.AddDirtyRect when the contents of the render target are updated.
From the code you provided it is not clear if you are doing all initializations only once or not, so try to call any initialization code only once and reuse the render target - just clear it at the beginning of every frame. This is mandatory to get a decent performance.
Update: SharpDX.Toolkit has been deprecated and it is not maintained anymore. It is moved to a separate repository.