c# - How to requery 'CanExecute' of a single RoutedCommand? -

i need refresh canexecute state of 1 or more (though far not all) routedcommand objects.

i know you can update commands using

commandmanager.invalidaterequerysuggested(); 

since updates far more commands necessary, calling function performance problem in application.

my initial hope calling canexecute() manually raise event if state changed, not case.

when looking @ reference source then, canexecutechanged not seem accessible derived classes provide kind of extension routedcommand class allows raising event manually.

public event eventhandler canexecutechanged {     add { commandmanager.requerysuggested += value; }     remove { commandmanager.requerysuggested -= value; } } 

any ideas how implement such mechanism? know delegatecommand, need routed command, don't think class can me.

you can create own custom routedcommand, reimplement icommand , register additional event yourself. note using new supposedly safe here because wpf use icommand reference call canexecutechanged.

public class myroutedcommand : routedcommand, icommand {     private event eventhandler _canexecutechanged;      public void raisecanexecutechanged()     {         var handler = _canexecutechanged;         if (handler != null) handler(this, eventargs.empty);     }      public new event eventhandler canexecutechanged     {         add         {             _canexecutechanged += value;             base.canexecutechanged += value;         }         remove         {             _canexecutechanged -= value;             base.canexecutechanged -= value;         }     } } 

you should aware while wpf use weakeventmanager register event, others devs might not. since routed commands defined static fields, potential memory leak. implement weak event manager prevent this.