Serious flaw in WPF validation infrastructure for ValidationRule and Binding
Adam Nathan's excelent book on WPF states:
The validation check is invoked during any attempt to update the underlying data ... before a value converter is called (if present)...
This is further reinforced on MSDN where the validation process is explained:
I can't understand how this design decision was made (it seems to be very much a rational decision, given how well documented it is).
Think about this scenario: you want to validate an integer value for a property (say, its range). There is a built-in converter for integers (but this could be a custom value converter, if it was your own type) that will ultimately assign a value of the right type to the property....