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I have a user control with a Button bound to the NavigationCommands.RefreshCommand. The handler for the command is in the parent control. The handler's CanExecute looks like this:

e.CanExecute = !IsConnecting; // IsConnecting is a Dependency Property

For some reason, the Button will remain disabled until I click on the window.

If I click the Button and get it to execute (which causes IsConnecting to temporarily be set to true) it will then disable the button correctly, but won't enable the button until I cause another event in the window (eg. a click).

Are there any tools or tricks I can use to try debug the CanExecute handler of a command which is bound to a button?

Dave Clemmer
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vanja.
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1 Answers1

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The button's CanExecute is only called when something happens in the GUI. Since the IsConnecting changes in the background then WPF doesn't update the control.

To force WPF to update the CanExecute call CommandManager.InvalidateRequerySuggested

Cameron MacFarland
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  • I have called the InvalidateRequerySuggest() in DataErrorInfo index method. But CanExcecute not being called again. So even my data is valid on UI, button command button is not enabling. – Nps Sep 19 '12 at 04:18