Set a callback method in a DataTemplate - wpf

Question

I have a listbox of custom items set through a DataTemplate.
<UserControl x:Name="MyMainControl">
<ListBox x:Name="lbConfigurationList"
DataContext="{Binding DataContext, RelativeSource={RelativeSource AncestorType={x:Type Window}}}"
ItemsSource="{Binding ConfListVM.ObservableConfList}"
SelectionChanged="OnConfigurationSelected"
<ListBox.ItemTemplate>
<DataTemplate>
<local:EditableTextBlock Text="{Binding ConfName}" />
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</UserControl>
Is it possible to call a method on the control owning this listbox each time someting happens in the EditableTextBlock, through something like:
<local:EditableTextBlock Text="{Binding ConfName}" MyNotifyEvent={SomeMyMainControlMethod} />
If this is possible, which terms should I search to understand how to setup and launch the event from my DataTemplate's EditableTextBlock?
Thanks in advance

Answer 1

Here is a full example using Behaviors:
<Window x:Class="TextBlockEventHandlerInDataTemplate.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
xmlns:local="clr-namespace:TextBlockEventHandlerInDataTemplate"
Title="MainWindow" Height="350" Width="525">
<Grid>
<ListBox ItemsSource="{Binding items}">
<ListBox.ItemTemplate>
<DataTemplate>
<TextBox Text="{Binding ., Mode=TwoWay}" >
<i:Interaction.Behaviors>
<local:ShowMessageOnTextChangedBehavior/>
</i:Interaction.Behaviors>
</TextBox>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Grid>
Codebehind, sorry i didn't have time for MVVM approach:
public partial class MainWindow : Window
{
public ObservableCollection<string> items { get; set; }
public MainWindow()
{
InitializeComponent();
items = new ObservableCollection<string>();
items.Add("item 1");
items.Add("item 2");
items.Add("item 3");
items.Add("item 4");
this.DataContext = this;
}
}
And this should be your class doing the job:
public class ShowMessageOnTextChangedBehavior : Behavior<TextBox>
{
protected override void OnAttached()
{
AssociatedObject.TextChanged += AssociatedObjectOTextChanged;
base.OnAttached();
}
protected override void OnDetaching()
{
AssociatedObject.TextChanged -= AssociatedObjectOTextChanged;
base.OnDetaching();
}
private void AssociatedObjectOTextChanged(object sender, RoutedEventArgs routedEventArgs)
{
MessageBox.Show(AssociatedObject.Text);
}
}
The other thing would be to define an attached property. I use both ways, depending on the mood :)
Ah, i was about to forget an important thing: you need to reference
Microsoft.Expression.Interactions and System.Windows.Interactivity from Expression.Blend.SDK.