Note that the Text Block will appear on top of any elements that are located right below the Text Box as adorners are always visually on top.Now that you can see the actual error message, which reads “Value …A converter class converts data from one type to another during binding by implementing the Convert and Convert Back methods of the mentioned interface.Once you have created a converter class you will typically add it as a resource in XAML with a unique x: Key attribute and then reference it from the binding as a Static Resource: (string) to a dependency property of type string you don’t necessarily need to use a converter as the default conversion will automatically apply the To String() method on the value of the source property.
The dependency property does the rest – and that’s that!
The latter can for example be very useful for bindings in Styles and Control Templates and when you want to bind to some property in a parent element.
The Mode property of the , which is the default for the Text property of the Text Box control, the text you type into the Text Box does not update the source property until the control loses focus which happens when you click away from it. the setter for the bound property of the Data Context to get called, as the user is typing into the Text Box you set the Update Source Trigger property to enumeration.
This means that you don’t have to use a converter to display a If a user enters an invalid value that cannot be converted to an int and be set as the value for the Age property in the view model in the above example, a validation error will occur and a visual feedback will be provided to the user to indicate this.
By default you will see a red border around the UI element when this happens, e.g.