CODEWITHSUNDEEP
wpfbindingcommand
David Ward
David Ward

Reputation: 3829

WPF command not executable

I have a button on a toolbar that has its command set to "MyControl.Print" (for example). In the control the command is added to the command bindings including both the Execute and CanExecute.

The control is within a window with other controls docked appropriately. I am finding that for the Print button to be enabled I have to "select" MyControl first which does not provide a good user experience and indeed causes various "bugs" being raised and lots of confusion.

Is there a way that I can ensure that the button is enabled whether or not the control has been "selected"?

Upvotes: 0

Views: 442

Answers (2)

Chris Hagan
Chris Hagan

Reputation: 2437

Since the CanExecute doesn't fire, I think you might be looking at the major downside to RoutedCommands - the way they tunnel and bubble can leave a highly composed interface unable to have commands arrive anywhere useful. For this reason we ended up moving to DelegateCommands from (I think) the Microsoft CAG. Not any of the other stuff, just the commands. Works a lot better, and isn't tied in to the interface so tightly.

Oh, the other response raises a good point. I assumed you meant that to ever print, your MyControl needed to have keyboard focus. Is it only the first time and after that it works?

I recommend http://msdn.microsoft.com/en-us/library/ff921126(PandP.20).aspx as a pretty good starting point. You don't have to worry too much about the IActiveAware up front, since you're hoping for this command to be available all the time (or at least let its availablity be determined by CanExecute).

Upvotes: 1

David Kiff
David Kiff

Reputation: 1210

CommandManager.InvalidateRequerySuggested will force the command manager to re-call all of your CanExecute methods and should disable the button. Perhaps call that onload?

Upvotes: 1

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