Thread: two child windows, help!!!

hello,

I already know how to create MDI child windows, from the WM_COMMAND of the frame window clicking on the "menu new" everytime i need a new child window. but what i need is to have only 2 static child windows , my program should not be able to create more than 2, this 2 windows must be visible from the start of the program, and must have completly different behivor and controls, but of course both are of the same "Class",i cant figure out how can i do that, must i create 2 childProc's? 1 for every window with its own WM_CREATE to add its conotrols? with WindowCreateEx() or from 1 childProc can i define the controls, etc of both windows? ,

i ask this because if i define just 1 childproc, both windows have exactly the same controls, etc,

what i need is the theory of this, or whats the general idea to perform this.

thanks for any help, i really need that
please excuse my poor enhlish

If the mdi child windows are of the same window 'class' then they'll have the same window procedure, which you can override if you want by subclassing (old article but still useful). Or you could just determine which mdi child window a message is for in the window 'class' mdi child window procedure and forward it to another function which would act as the window procedure. On the other hand, if your intention is to have mdi child windows for different purposes then you should probably register each with a unique window 'class' - which includes providing them with separate window procedures.

AFAIK MDI children send WM_COMMAND msg's to thier parent. In some cases it may be WM_NOTIFY.
The child ID will be the low order word of the wParam, the lParam is the childs HWND.

I prefer to write each child a callback, easier to debug later.


//from windowsx.h
idControl = GET_WM_COMMAND_ID( wParam, lParam) ;

GET_WM_COMMAND_ID is a macro defined in windowsx.h (look for it in your header files) and should only be used in the context of the parent's WM_COMMAND handler. You can also use LOWORD(wParam) in the same context and with the same result ie to get the identifier for that particular control (provided lParam is non-NULL).

To get the identifier for the mdi child window in the WM_CREATE handler of the mdi child window as you seem to be trying to do then use GetWindowLongPtr.

If you want to get the id of the mdi child window in response to a WM_MDI_ACTIVATE message, like in your earlier post then:

Code:

case WM_MDIACTIVATE:
  {
  int nID=(int)GetWindowLongPtr(hwnd,GWLP_ID);
  sprintf(cadena,"%d",nID);
  MessageBox(hWnd,cadena,"Mensaje",MB_OK);
  break;
  }