用于检查是否已在Flex中编辑任何组件的全局标志

I need to use a global flag. This flag will be set whenever I change my datagrid i.e. add/ update rows, change checkboxes, radiobuttons, etc. in my screen. Also, on what event can this global variable be set. Will "change()" or "click()" work. Need some idea in this context.I need to use a global flag. This flag will be