Question

The Window-Procedure in the Win32 API must be static \ global function since it cannot take a class-object (the this) parameter. One can of-course use workarounds like a hWnd->object dictionary and such.

I wonder if D has a way to elegantly solve it, like create a tiny member function copy for each object (to call the object’s real handler) or anonymous function that I can assign to WNDCLASS.lpfnWndProc (I know there are anonymous functions, but I cannot use the extern(Windows) property on them) ?

Can I do something like this :

---

class Window {
    extern (Windows)
    LRESULT delegate (HWND hWnd, UINT msg, WPARAM w, LPARAM l) MyWinProcDelegate;

    this() {
        MyWinProcDelegate = &Events;
    }

    extern (Windows)
    LRESULT Events (HWND hWnd, UINT msg, WPARAM w, LPARAM l) {
        MessageBoxA(null , "Success!!!" , null ,0);
        return DefWindowProcA(hWnd, message, wParam, lParam);
    }
}

---

(Omitting the registration\creation\msg-loop…)

The Events() doesn’t seem to fire… am I missing something ?

Answer 1

How about storing this in the window itself, with SetWindowLong?