SilverPlusEllipse

SilverScreen and MFC

SilverScreen is built as an MFC document/view application, using SDI (Single Document Interface). This means that SilverScreen contains a main frame window implemented by a class derived from CFrameWnd, and a single view window derived from CView. The main frame window contains the usual assortment of user interface items, including a main menu, ribbon and status bar. The view window is where SilverScreen drawings are displayed.

SilverScreen's MFC Architecture

The following figure shows the general structure of SilverScreen's architecture. Note that the status bar and individual ribbons may be enabled or disabled as the user wishes.

MFCArchitecture

Getting Handles

When subclassing SilverScreen windows, the windows that we are usually interested in are the main frame window and the view window. In order to subclass them, we must have their window handles. The main frame window handle may be obtained by calling the MFC function AfxGetMainWnd() to obtain a CFrameWnd pointer, and then calling the CFrameWnd's member function GetSafeHwnd(). The return value is the main frame window handle. The view window handle may be obtained by calling the CFrameWnd member function GetActiveView() to obtain a CView pointer, and then calling its GetSafeHwnd() member function. The following piece of code demonstrates the technique.

C / C++ Code

void GetFrameAndViewWindowHandles()

{

CFrameWnd *mf;

CView *v;

HWND frame_handle = 0;

HWND view_handle = 0;

if ( mf = (CFrameWnd *) AfxGetMainWnd() )

{

frame_handle = mf->GetSafeHwnd();

if ( v = mf->GetActiveView() )

view_handle = v->GetSafeHwnd();

}