UserControl Binding

Question

Hey,

I have a problem with UserControls and bindings:

I want to bind to a UserControl called HeaderedTextBlock using a converter like this:

<controls:HeaderedTextBlock Header="Header 2" Text="{Binding Converter={StaticResource converter}, ConverterParameter=Title}" />
>

The converter returns a string object..

This is HeaderedTextBlock.cs:

public sealed partial class HeaderedTextBlock : UserControl
    {
        public string Header
        {
            get
            {
                return header.Text;
            }
            set
            {
                header.Text = value;
            }
        }
        public string Text
        {
            get
            {
                return content.Text;
            }
            set
            {
                content.Text = value;
                this.Visibility = (string.IsNullOrWhiteSpace(value)) ? Visibility.Collapsed : Visibility.Visible;//hide if empty
            }
        }
        public HeaderedTextBlock()
        {
            this.InitializeComponent();
        }
    }

The UserControl works fine as long as you do not bind one of its properties.

I set a breakpoint in the converter, but the exception occurs even before the converter is called. The very same Text="..." works fine with a TextBlock control.

How do I have to modify the UserControl to support binding?

thanks in advance,

~theCake

---

Life is unsure - always eat the dessert first!

Answer 1

Try making the target property you want to bind to a dependency property:

        public string Text
        {
            get { return (string)GetValue(TextProperty); }
            set { SetValue(TextProperty, value); }
        }

        // Using a DependencyProperty as the backing store for Text.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty TextProperty =
            DependencyProperty.Register("Text", typeof(string), typeof(MyUserControl1), new PropertyMetadata(string.Empty));

---

http://babaandthepigman.spaces.live.com/blog/

Answer 2

Thanks!

I found this to be the best approach to bind to the DependencyProperty "Text":

<UserControl ... x:Name="self">
...
    <TextBlock Text="{Binding Text, ElementName=self}" />
...        
</UserControl>

cheers,

~theCake

---

Life is unsure - always eat the dessert first!