How to do communication between an object and its clone? - wpf

Question

I have an object and one clone of the same object. First one is added in one panel(canvas) as a child and the second one is added to another panel as a child. Now, if I am doing some operations(say delete) on the main object, what is the best way in which the clone object also get notified(deleted). Basically, I am looking for how to create a link between a object and it's clone?
Thanks

Answer 1

Given the details, if you want both to always be in sync then I would rather suggest to 'avoid the clone'. Make the two work on the same instance, unless you have better reason to maintain the clone.
If there is some set of properties that you want to sync, then consider moving those to a different class and make the two (original and clone) share that instance.
Something like this:
public class PartiallyCloneable{
public SharedValue Shared{get;set;}
public ClonedValue Cloned{get;set;}
public PartiallyCloneable Clone(){
//deep copy ClonedValue, return same instance of SharedValue
}
}
public class SharedValue{
}
public class ClonedValue{
}

Answer 2

There's no simple direct way to do that, and adding the same object to multiple parents will throw exception. So you need to write a few lines of code. My guess is your approach is somehow a difficult one and you need to rethink the problem. Let me give you some ideas:
If you're using MVVM pattern (or you want to choose the standard path), define a ViewModel (which should derive from DependencyObject) for your object and bind the DataContext of both objects to one instance of this ViewModel. So that both View objects reference the same ViewModel. Then use Commands to do stuff to either objects.
If you don't want to go that far, use the same style for object and its clone, and set event handlers inside that style.
<Style x:Key="myStyle" TargetType="Control">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate>
<Border BorderThickness="1" BorderBrush="Black" Unloaded="objectUnloaded">
<StackPanel>
<TextBlock Text="something"/>
<Button Content="delete" Click="deleteButtonClicked"/>
<Button Content="otherStuff" Click="otherStuffButtonClicked"/>
</StackPanel>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
Also bind the Tag of each object to other.
<Control x:Name="main" Style="{StaticResource myStyle}"
Tag="{Binding ElementName=clone}"/>
<Control x:Name="clone" Style="{StaticResource myStyle}"
Tag="{Binding ElementName=main}"/>
Now if you implement those event handlers in code behind, you can access both object and clone at the same time:
private void otherStuffButtonClicked(object sender, RoutedEventArgs e)
{
var obj = sender as FrameworkElement;
var other = (obj.TemplatedParent as FrameworkElement).Tag;
//do stuff to obj
//do stuff to other
}