How to access ID2D1HwndRenderTarget->Resize using C++ builder TDirect2DCanvas - c++

Question

I've been trying to use TDirect2D in my c++ builder project. I've been using the following code to gain access to Direct2D Canvas.
void __fastcall TCustomDrawPanel::Paint()
{
if ( TDirect2DCanvas::Supported() )
{
std::unique_ptr<TDirect2DCanvas> D2DC(
new TDirect2DCanvas( Canvas, ClientRect )
);
struct DrawSession {
explicit DrawSession( TDirect2DCanvas& Canvas )
: c_( Canvas ) { c_.BeginDraw(); }
~DrawSession() {
try {
c_.EndDraw();
}
catch ( ... ) {
}
}
TDirect2DCanvas& c_;
}
D2DSession( *D2DC );
DDrawPanel(D2DC);
}
This code works fine, but the Direct2D resources have to be acquired and released on each repaint. So I'm using the example found On Embarcadero website. For that example to work properly I'll have to resize the render target when ever the window is resized. The example given on the website is in Delphi as shown below.
procedure T2D2Form.WMSize(var Message: TWMSize);
begin
if Assigned(FCanvas) then
ID2D1HwndRenderTarget(FCanvas.RenderTarget).Resize(D2D1SizeU(ClientWidth,
ClientHeight));
inherited;
end;
My question is how can I convert this to c++ builder code? I've tried many different ways to cast FCanvas->RenderTarget but the code won't compile.
I've tried the following:
ID2D1HwndRenderTarget * target =
dynamic_cast < Winapi::D2d1::ID2D1HwndRenderTarget * > (FCanvas->RenderTarget);
I can use target->Resize(D2D1SizeU(ClientWidth, ClientHeight)) to change render size if I can get the code to compile.