make defaultable values validatable

[dzmitry-lahoda]

https://docs.microsoft.com/en-us/dotnet/api/system.componentmodel.dataannotations.ivalidatableobject.validate .

[SteveDunn]

Hi @dzmitry-lahoda - visiting some old comments now that I've got a bit of time free. Do you mean to make the generated code IValidatableObject?

[dzmitry-lahoda]

yes, so it will depend on componentmodel. and may be using validation attributes support on ctor parameters us enough. so that when error is raised it looks noce in xaml or api.