Copy a ID3D10Texture2D surface to a HBitmap

Question

Hey, guys:
I want to draw some items on a trasparent window with d3d10, first I create a Layed window and hope to use UpdateLayedWindow to refresh items, then create a HBitmap hope to copy the surface of a d3d10 rendertargetview, and then bind HBitmap to a CompatableDC, so it can be painted when UpdateLayedWindow is called.
When it finished drawing with direct3d, I can get a ID3D10Texture2D object which is queryed by ID3D10RenderTargetView, after Map it I can copy its contents to HBitmap. But I find that the result is not what I wanted(with some unexpected lines).

Why there are some unexpected lines, Anyone can tell me?

code in function Render():

{
  D3DXVECTOR4 clearColor(0.0f, 0.0f, 1.0f, 0.7f);
  m_pd3dDevice->ClearRenderTargetView(m_pRenderTargetView, (float*)clearColor);

  // rendering items
  // ...
  // end

  ID3D10Texture2D* pSrcResource = NULL;
  m_pRenderTargetView->GetResource(reinterpret_cast<ID3D10Resource**>(&pSrcResource));
  if ( m_pDstResource )
  {
     m_pd3dDevice->CopyResource(m_pDstResource, pSrcResource);
     D3D10_MAPPED_TEXTURE2D Data;
     hr  = m_pDstResource->Map(0, D3D10_MAP_READ, 0, &Data);
     if ( SUCCEEDED(hr) )
     {
         memcpy(m_pBits, Data.pData, 4 * m_size.cx * m_size.cy);
         m_pDstResource->Unmap(0);
     }
  }
  pSrcResource->Release();
  m_pSwapChain10->Present(0, 0);
 
  POINT ptWinPos = { m_rc.left, m_rc.top};
  POINT ptSrc = { 0, 0};
  SIZE szWin = { m_size.cx, m_size.cy };
  BLENDFUNCTION stBlend = { AC_SRC_OVER, 0, 255, AC_SRC_ALPHA };
  UpdateLayeredWindow(m_hWnd,GetWindowDC(m_hWnd),&ptWinPos,&szWin,m_hDC,&ptSrc,0,&stBlend,ULW_ALPHA);
}