CDialog::DoModal

Model Dialog in Win32 c++

Creating model dialog is very easy in MFC. It has neat class for dialog , CDialog. The DoModel functions of CDialog provides a way to appear model dialog.

 

In Win32 this is another story. Many people doesn't know what is a model dialog. Some may thought it is a special type of dialog, like the different window classes(EDIT,BUTTON etc) . Actually model dialog is just a modeless dialog with some additions. Creating a model dialog requires to create modeless dialog ( using CreateDialog ,or even CreateWindow(wnd) wnd = dialog class name).

 

Following is a sample class , which will show a modle dialog in win32, (Just like the CDialog::DoModal() in MFC).

 

class name CBaseDlg, In this class i wrote a function DoModel, see below.

The MyDlgProc is the dialog procedure function . In this procedure you can see that it calls the CBaseDialog::DialogProc function (blue color). So the derived class of CBaseDlg can override this function and add their command handlers.

 

LRESULT CALLBACK MyDlgProc(HWND hDlg,UINT nMsg,WPARAM wParam, LPARAM lParam)

{

     CBaseDlg* pWnd = NULL;

     pWnd = CBaseDlg::FromHandle(hDlg);

     if(pWnd)

            return pWnd->DialogProc(hDlg,nMsg,wParam,lParam);

     return FALSE;

}

 

void

CBaseDlg::DoModel(HINSTANCE hInst,HWND hParent,UINT nResourceID)

{

     HWND hwnd = CreateDialog(hInst,(LPCTSTR)nResourceID, hParent, (DLGPROC)MyDlgProc);

     HwndMaps.insert(std::pair<HWND,CBaseDlg*>(hwnd,this) ); //Add this hwnd for using in MyDlgProc.

    

     ShowWindow(hwnd,SW_SHOWNORMAL); //show dialog.

     SendMessage(hwnd,WM_INITDIALOG,0,0); ///send INIT_DIALOG message as usual.

     EnableWindow(hParent,FALSE);//Disable parent window

 

     MSG msg;

     while(GetMessage(&msg,0,0,0))

     {

         TranslateMessage(&msg);

        DispatchMessage(&msg);

      }

 

      EnableWindow(hParent,TRUE); 

      DestroyWindow(hwnd); //Destroy me

      HwndMaps.erase(HwndMaps.begin(),HwndMaps.end()); //Clear the window map , this is just like the MFC way in win32.

}

 

Here in DoModel Passing the parent window handle and resource id , It will show a model dialog. The inside message loop will prevent the function from returning . The parent window should be disable , otherwise still user can do on parent window. So by disabling the window , the only active window is the dialog.