Extracting Data from Messages with Portable Code

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The cleanest way to handle a repacked message is to revise your code so that it extracts needed information and stores it in local variables. This localizes message-packing issues to a few lines of your code.

For example, you can use the following code to handle the WM_COMMAND message:

          case WM_COMMAND:
            id = LOWORD(wParam);
            hwndChild = (HWND)(UINT)lParam;
            cmd = HIWORD(wParam);