Composite WPF Controls

Question

I am trying to create a multi-user UserControl in WPF with a shortcut and a text box. I want to add properties to my UserControl to bubble the Text fields of both child controls to the parent for easy binding. I read that I need to focus a bit by adding DependencyProperties owners. Here is my code now. It seems close, but not quite right. Any ideas?

Here is Xaml:

<UserControl x:Class="MAAD.AircraftExit.Visual.LabelTextBox" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Height="20" Width="300"> <DockPanel> <TextBlock Text="{Binding Path=Label, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}}" DockPanel.Dock="Left" TextAlignment="Right" Width="122" /> <TextBlock Text=": " DockPanel.Dock="Left"/> <TextBox Text="{Binding Path=Text, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}}" /> </DockPanel> </UserControl> 

And the code behind:

 public partial class LabelTextBox : UserControl { public static readonly DependencyProperty LabelProperty = DependencyProperty.Register("Label", typeof(string), typeof(LabelTextBox)); public string Label { get { return (string)GetValue(LabelProperty); } set { SetValue(LabelProperty, value); } } public static readonly DependencyProperty TextProperty = DependencyProperty.Register("Text", typeof(string), typeof(LabelTextBox)); public string Text { get { return (string)GetValue(TextProperty); } set { SetValue(LabelTextBox.TextProperty, value); } } public LabelTextBox() { InitializeComponent(); ClearValue(HeightProperty); ClearValue(WidthProperty); } } 

Edit: Here is the final working code. I switched to relative source binding.

Answer 1

Binding is really a way:

XAML:

 <UserControl x:Class="testapp.LabelTextBox " xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Height="300" Width="300" x:Name="This"> <DockPanel> <TextBlock DockPanel.Dock="Left" TextAlignment="Right" Width="70" Name="label" Text="{Binding Label, ElementName=This}" /> <TextBlock Text=": " DockPanel.Dock="Left" /> <TextBox Name="textBox" Text="{Binding Text, ElementName=This}" /> </DockPanel> 

Code for:

  public partial class LabelTextBox : UserControl { public LabelTextBox() { InitializeComponent(); Label = "Label"; Text = "Text"; } public static readonly DependencyProperty LabelProperty = DependencyProperty.Register("Label", typeof(string), typeof(LabelTextBox), new FrameworkPropertyMetadata(LabelPropertyChangedCallback)); private static void LabelPropertyChangedCallback(DependencyObject controlInstance, DependencyPropertyChangedEventArgs args) { } public string Label { get { return (string) GetValue(LabelProperty); } set { SetValue(LabelProperty, value); } } public static readonly DependencyProperty TextProperty = DependencyProperty.Register("Text", typeof(string), typeof(LabelTextBox), new FrameworkPropertyMetadata(TextPropertyChangedCallback)); private static void TextPropertyChangedCallback(DependencyObject controlInstance, DependencyPropertyChangedEventArgs args) { } public string Text { get { return (string) GetValue(TextProperty); } set { SetValue(LabelTextBox.TextProperty, value); } } } 

Answer 2

I did not understand why your implementation does not work, but I do not understand why you are doing this. Why not just define the dependency properties you need in the UserControl and then bind them to them?

 public static readonly DependencyProperty LabelTextProperty = ...; 

And then in your XAML:

 <Label Content="{Binding LabelText}"/>