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Databinding dropped in composite control with DP

Hi,

I have a databinding problem with a composite control I am creating.
The composite control consists of a Label and a TextBox, they both bind to dependency properties on the composite control, which then again binds to a property on an object defined in XmlDataProvider.
It seems that the databinding on the Text dependency property on the composite control is dropped/detached when I change the Text property on the TextBox is changed.

// UserControl1.xaml
<UserControl x:Class="CustomControls.UserControl1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<StackPanel Orientation="Horizontal">
<Label Name="label" />
<TextBox Name="textBox" />
</StackPanel>
</UserControl>

// UserControl1.xaml.cs
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;

namespace CustomControls
{
/// <summary>
/// Interaction logic for UserControl1.xaml
/// </summary>

public partial class UserControl1 : System.Windows.Controls.UserControl
{

public UserControl1()
{
InitializeComponent();

// --> Setup bindings
Binding labelContentBinding = new Binding("Label");
labelContentBinding.Source = this;
label.SetBinding(System.Windows.Controls.Label.ContentProperty, labelContentBinding);

Binding tbTextBinding = new Binding("Text");
tbTextBinding.Source = this;
textBox.SetBinding(TextBox.TextProperty, tbTextBinding);
// <-- Setup bindings
}

public static DependencyProperty LabelProperty =
DependencyProperty.Register("Label", typeof(string), typeof(UserControl1));

public static DependencyProperty TextProperty =
DependencyProperty.Register("Text", typeof(string), typeof(UserControl1));

public string Label
{
get { return (string)GetValue(LabelProperty); }
set { SetValue(LabelProperty, value); }
}

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

And here is an example:
<Window x:Class="CustomControlApp.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:customcontrols="clr-namespace:CustomControls;assembly=CustomControls"
Title="CustomControlApp" Height="300" Width="300"
>
<Window.Resources>
<XmlDataProvider x:Key="Family" XPath="/Family/Person">
<x:XData>
<Family xmlns="">
<Person Name="Tom" Age="9" />
<Person Name="John" Age="11" />
<Person Name="Melissa" Age="36" />
</Family>
</x:XData>
</XmlDataProvider>
</Window.Resources>
<StackPanel Orientation="Vertical" DataContext="{StaticResource Family}">
<StackPanel Orientation="Horizontal">
<Label Content="{Binding XPath=@Name}" />
<TextBox Width="100" Name="textBox2" Text="{Binding XPath=@Name}" />
</StackPanel>
<customcontrols:UserControl1 Label="{Binding XPath=@Name}" Text="{Binding XPath=@Name}" />
</StackPanel>
</Window>

Hope someone can help me solve this.

Jesper Kleis Jensen

In your scenario, you should mark the binding on the Text DP as a TwoWay binding:

Zhou Yong

Thank you, I can't believe I missed that ;)

Jesper Kleis Jensen

reply 3