Ignoring Listcontrol 'DELETE_ALL_ITEMS' Event when closing application

Question

I have a MFC ListControl in my application. I have an event that occurs when "all items in the view were deleted". The event throws an error message and then closes the program.

My problem is that the event also gets called if the X(close) button is clicked.

Here is my code for the LVN_DeleteAllItems event:

void Users::OnLvnDeleteallitemsList1(NMHDR *pNMHDR, LRESULT *pResult)
{
    LPNMLISTVIEW pNMLV = reinterpret_cast<LPNMLISTVIEW>(pNMHDR);
    MessageBox("The SQL connection has been dropped.  Please restart the application.","SQL Connection Error",MB_ICONSTOP);
    exit(EXIT_FAILURE);
    *pResult = 0;
}

Is there a way to keep the event from being called if the application is closed correctly (with the button in the top right corner)?

Answer 1

This is the normal behavior. When the X button gets pressed, the main window receives a WM_CLOSE, and start to call its children destructors. When the ListView destructor is called all its item are cleaned up, so there goes your LVN_DeleteAllItems notification.

The (logical) error is that the connection to the DB being dropped test is being performed here (and also the abnormal exit procedure). Here only ListView additional tasks should be performed. The database connection check should be handled higher in the callstack: a good example is the place in the code that sent the LVM_DeleteAllItems (note the LVM_DeleteAllItems), and triggered the ListView to be emptied.