FrameworkElementFactory.AddHandler not working

[Michael]

I am using a RadPropertyGrid. I am trying to use the AutoGeneratingPropertyDefinition event to provide a custom EditorTemplate with a textbox. I want to add a handler to the TextChanged event of the textbox but my event handler is never being called.

Relevant code:

public void GeneratingProperty(AutoGeneratingPropertyDefinitionEventArgs e)
{
    try
    {
        AvailableProperties property = (AvailableProperties)Enum.Parse(typeof(AvailableProperties), e.PropertyDefinition.Binding.Path.Path);
        if (IsAvailable(item.GetAvailableProperties(), property))
        {
            switch (property)
            {
                case AvailableProperties.Title:
                    FrameworkElementFactory textBoxFactory = new FrameworkElementFactory(typeof(TextBox));
                    textBoxFactory.AddHandler(TextBox.TextChangedEvent, new TextChangedEventHandler(TitleTextChanged));
                    textBoxFactory.SetValue(TextBox.BackgroundProperty, System.Windows.Media.Brushes.Tomato);
                    textBoxFactory.SetValue(TextBox.BorderBrushProperty, System.Windows.Media.Brushes.Transparent);
                    textBoxFactory.SetBinding(TextBox.TextProperty, new Binding("Title"));

                    DataTemplate template = new DataTemplate();
                    template.VisualTree = textBoxFactory;
                    template.Seal();

                    e.PropertyDefinition.EditorTemplate = template;
                    e.PropertyDefinition.OrderIndex = 0;
                    e.PropertyDefinition.DisplayName = "Title";
                    e.PropertyDefinition.Description = "The title of the attribute. Can only contain letters, numbers, and underscores.";

                    break;
                default:
                    // other properties go in case statements above here
                    break;
            }
        }
        else
        {
            e.Cancel = true;
        }
    }
    catch
    {
        e.Cancel = true;
    }
}

public void TitleTextChanged(object sender, TextChangedEventArgs e)
{
    if (sender is TextBox)
    {
        TextBox titleTextBox = (TextBox)sender;
        int caretIndex = titleTextBox.CaretIndex;
        string newValue = titleTextBox.Text;

        item.Title = newValue;
        ApplyCorrectedValue(newValue, item.Title, titleTextBox, caretIndex);

        NotifyOfPropertyChange(() => MappingsPanel);
    }
    else
    {
        Logger.Log("TitleChanged: source must be a TextBox");
        throw new ArgumentException("source must be a TextBox");
    }
}

I am using the 2012.2.912.35 version of the telerik dlls

[Ivan Ivanov]

Hi,

Unfortunately, this is a framework limitation of WPF. DataTemplates constructed with FrameworkElementFactory lose their event subscriptions, as soon as DataTemplate.LoadContent() gets invoked. In case you are willing to upgrade to a newer version, we have recently introduced a FieldLoaded event, where you can access the editor and subscribe to some of its events.

Greetings,
Ivan Ivanov
the Telerik team

[Michael]

Hi Ivan,

That doesn't seem right. I have written another small WPF application that just has a content control which uses a button created in a FrameworkElementFactory.

C# Code:

void btn_Click(object sender, RoutedEventArgs e)
{
    MessageBox.Show("Clicekd!");
}

private void cc1_Loaded(object sender, RoutedEventArgs e)
{
    FrameworkElementFactory fef = new FrameworkElementFactory(typeof(Button));
    fef.AddHandler(Button.ClickEvent, new RoutedEventHandler(btn_Click));
    fef.SetValue(Button.ContentProperty, "Button2");
    DataTemplate dt = new DataTemplate();
    dt.VisualTree = fef;
    dt.Seal();
    dt.LoadContent();
    (sender as ContentControl).ContentTemplate = dt;
}

XAML:

<Grid>
    <ContentControl x:Name="cc1" Grid.Row="0" Loaded="cc1_Loaded"/>
</Grid>

This code calls the event handler call-back when the button is pressed.

Regards,
Michael

[Kristoffer]

Any news regarding this? I'm trying to build a template in code behind (to solve this).

My event handler isn't working :(

buttonElement.AddHandler(Button.ClickEvent, new RoutedEventHandler(SelectFile));

[Ivan Ivanov]

Hello,

Unfortunately this is a framework limitation of WPF. I have prepared a sample project that demonstrates it out of the scope of RadControls. You can see the difference between XAML defined DataTemplate and FrameworkElementFactory.

Regards,
Ivan Ivanov
Telerik

[JC]

That is FieldLoaded event ?, I could give an example  please?ç

Thanks.

Jose Carlos Vasquez.

[Dimitrina]

Hello Jose,

I am not sure that I understand your questions properly. Would you please be more specific and explain in details? 

Regards,
Didie
Telerik