xamlselectionchanged

XAML ComboBox SelectionChanged Fires OnLoad


If I have a ComboBox that has a SelectionChanged event, it fires when I'm loading the control.

So at page load I set the SelectedValue and the SelectionChanged event fires which is not what I want to happen.

What is the accepted apporach to stopping this?


Solution

  • Two obvious solutions to this would be 1) Wait until the Loaded event of the Window/Page/UserControl which contains the ComboBox and hook up SelectionChanged there...eg in the constructor:

    // set the inital selected index for the combo box here...
    
    this.Loaded += (s, args) =>
                   {
                        cmbBox.SelectionChanged += 
                                new SelectionChangedEventHandler(HandleChanged);
                   };
    

    or 2) Check that the ComboBox has loaded in the selection changed handler before doing anything and return if it hasn't...eg in the handler:

    if (!cmbBox.IsLoaded)
            return;
    

    I would prefer number 1 as it doesn't require the check every time the SelectionChanged handler is fired.