Getting many Binding "Information" in WPF output window

Question

When I start my app I get alot information like this:

System.Windows.Data Information: 10 : Cannot retrieve value using the binding and no valid fallback value exists; using default instead. BindingExpression:Path=Period; DataItem=null; target element is 'TextBlock' (Name=''); target property is 'Text' (type 'String')

System.Windows.Data Information: 10 : Cannot retrieve value using the binding and no valid fallback value exists; using default instead. BindingExpression:Path=DocumentId; DataItem=null; target element is 'TextBlock' (Name=''); target property is 'Text' (type 'String')

Should I care for that output?

Answer 1

Yes, you should. It is safest to treat binding feedback (information, errors, etc) just like compiler warning and errors. Binding issues tend to slow the execution of the application down since it forces bindings to be re-evaluated, and in my experience, sometimes breaks them to where you need to recreate the binding in code.

The simplest workaround, if you can, is to set the FallbackValue on your binding to a value which can be treated as default. For example, if you have a class which has a "Count" property, but said class can be null at some point in time when your view is created, your binding might look like <TextBlock Text={Binding Count, FallbackValue=0} /> which would display a "0" in the text block, or pass the fallback value to the converter if there is one in use.