WM_COMMAND and the difference WM_LBUTTONDOWN

INT_PTR CALLBACK DialogProc(HWND hwndDlog, UINT uMsg, WPARAM wParam, LPARAM lparam)
{//消息回调函数
    switch (uMsg)
    {
    case WM_COMMAND:
        if (LOWORD(wParam) == IDOK)
        {
            float left1 = GetDlgItemFlaot(hwndDlog, IDC_LEFT1);
            float right1 = GetDlgItemFlaot(hwndDlog, IDC_RIGHT1);
            SetDlgItemFloat(hwndDlog, IDC_RESULT1, left1 + right1);
        }

　　　　　if (LOWORD(wParam) == IDCANCEL)
        {
            EndDialog(hwndDlog, IDCANCEL); 
        }
        break;
    }
    return FALUSE;
}

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WM_COMMAND: from the menu item or keyboard shortcut button control and so on.

Here a message is received to the page among the operations caused by the matching and parsing ,, i.e. the same message and performs a corresponding operation.

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INT_PTR CALLBACK msgProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
    switch (uMsg)
    {
    case WM_INITDIALOG:
        SetWindowText(hwnd, "简单的");
        break;
    case WM_CLOSE:
        EndDialog(hwnd, WM_CLOSE);
        break;
    case WM_LBUTTONDOWN:
    {
        char s[256];
        int x = LOWORD(lParam);
        int y = HIWORD(lParam);
        sprintf(s, "鼠标左键点击:x:%d,y:%d", x, y);
        SetWindowText(hwnd, s); 
    }
        break;
    }
    return FALSE;
}

 

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Since this presses the left mouse button and the corresponding content is not visible WM_COMMAND WM_LBUTTONDOWN message contains belongs.

Can be understood, when an OK button is pressed, the button because there is a corresponding ID, you will find the message corresponding WM_COMMAND ID generated at the time of the response.

But when the click of a mouse or keyboard when the ID does not correspond with it, but there's incident response and this corresponds to that WM_LBUTTONDOWN.