wpf - 这些事件是什么时候提出的，它们之间有什么关系？“CommandBinding的CommandManager.CanExecute和CanExecute

Question

这些事件是什么时候提出的，它们之间有什么关系？“CommandBinding的CommandManager.CanExecute和CanExecute？？？

Answer 1

The CanExecute event of a CommandBinding is fired when the CommandBinding believes something changed that could affect the state of the command. This is primarily when the user interacts with the UI in some way (mouse moves, clicks, focus changes, etc.), or when a user action causes a PropertyChanged or CollectionChanged event. This event does not get fired when your code changes something in the UI, or causes a PropertyChanged event to fire.

Is there a specific situation you have in mind?

The CommandManager.CanExecute method is a way to attach a CanExecute event handler to a UI element, so that when the CanExecute of the RoutedUICommand bubbles up the visual tree, it can trigger your CanExecute event handler. It is just a different way to attach a CanExecute event to an element for different scenarios, but the end result is the same as adding a CommandBinding to the CommandBindings collection of a UIElement.