Is there a way of undoing a selection a user makes with the combo box?

In WPF 3.5, is there a property of the com开发者_如何学Pythonbo box will allow the user to undo the selection they've made?

Code

If you look to a way to reset the selection from code (you wrote a property), try the following:

cboYourCombo.SelectedIndex=-1

or

cboYourCombo.SelectedItem=null;

Keyboard Shortcut

If you look for a keyboard shortcut to reset, I've never seen. But if you want, you can do it on your own, it's probably easy:

Attach an EventHandler to the PreviewKeyDown-event of your combobox (or register a general event-handler that works for all comboboxes in your window/app), check the key and if its the key you want to reset, use the code above to reset the selection. Please note, in the PreviewKeyDown-event you can also check for special-keys such as the control-key.

Provide an empty Value

However I think, better would be to add an empty entry and then preselect this empty value. If the user has changed the selection and wants to reset, he can select the empty value. Otherwise you change the standard UI-behaviour and not all people like this.

What do you mean by "undo"? Do you mean something like CTRL+Z (or an undo button), or something like CANCEL? Implementing true undo/ctrl+z on a combo box is something very few applications do, and it will surprise the user. This is a very bad idea, unless you have a very good reason.

If you have a very good reason to go against the design of most windows apps, you can add a handler for SelectionChanged, and implement your own history. Then, if the user either uses a keydown (ctrl+z), or clicks an "undo" button, you can set the selection yourself.

Alternately, if you don't really want an UNDO feature, and actually want a CANCEL feature (a common feature in UI apps), then you shouldn't worry about each control individually. Just keep a set of stored settings (in some custom class), and set all the controls back to the values that were stored. In the case of a combo box, you'd want to set the Selection property.