WPF Nested binding in a controltemplate

Question

I have successfully created a textbox that displays / collapses an error message depending upon a validation rule set in its model / vm. The code goes like this for the emai

Answer 1

You won't need the Grid.Row and Grid.Column bindings in the Template StackPanel since the StackPanel won't be the direct child of a Grid anyway,

TemplateBinding is always a OneWay binding so the Text property for the Templated TextBox will never get updated. Change it to a regular Binding with RelativeSource and TwoWay

Change ElementName=validableText to RelativeSource={RelativeSource TemplatedParent} in the bindings for ContentPresenter since we want to perform the validation check on the Templated TextBox and not the TextBox inside the Template.

On a side note, another alternative that you have here is to create a UserControl with the original piece of Xaml that you had. You could introduce the Dependency Properties needed for your scenario (Text etc.). It would only require small changes.