title: WPF Command Class Override CanExecuteChanged-Event?
body: <p>At the moment I have the following Command class:</p>
  
  <pre><code>Public Class SubscribeCommand
      Implements ICommand
  
      Private ReadOnly _vm As MainWindowViewModel
  
      Public Sub New(ByVal vm As MainWindowViewModel)
          _vm = vm
      End Sub
  
      Public Function CanExecute(ByVal parameter As Object) As Boolean Implements System.Windows.Input.ICommand.CanExecute
          Return Not String.IsNullOrEmpty(_vm.Symbol)
      End Function
  
      Public Event CanExecuteChanged(ByVal sender As Object, ByVal e As System.EventArgs) Implements System.Windows.Input.ICommand.CanExecuteChanged
  
      Public Sub Execute(ByVal parameter As Object) Implements System.Windows.Input.ICommand.Execute
          _vm.Subscribe()
      End Sub
  End Class
  </code></pre>
  
  <p>In a tutorial i read, you have to implement add {} and remove {} for the canExecuteChanged-Event. But how can i do that, with vb.net?</p>
  
  <p>thanks a lot..</p>