Question

I want to create my own class to handle creating windows and the window procedure but I have noticed that the window procedure has to be static! I’m now wondering whether its possible to make the window procedure object oriented? I have read some tutorials on object oriented windows, but they always make the procedure static -.- whats the use in that? :/

Any links or info on how to get around this problem would be appreciated,

thanks

Answer 1

You can get around that by making the static WndProc delegate everything to the members:

// Forward declarations
class MyWindowClass;
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)

std::map<HWND, MyWindowClass *> windowMap;

// Your class
class MyWindowClass  {
private:
  HWND m_handle;

  // The member WndProc
  LRESULT MyWndProc(UINT message, WPARAM wParam, LPARAM lParam) { /* ... */ }

public:
  MyWindowClass()
  {
    /* TODO: Create the window here and assign its handle to m_handle */
    /* Pass &WndProc as the pointer to the Window procedure */

    // Register the window
    windowMap[m_handle] = this;
  }
};

// The delegating WndProc
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
  std::map<HWND, MyWindowClass *>::iterator it = windowMap.find(hWnd);
  if (it != windowMap.end())
    return it->second->MyWndProc(message, wParam, lParam);
  return 0;
}