ParentContext is not accessible unless casting ValidationContext<T> to IValidationContext

FluentValidation version

10.0.0

ASP.NET version

.NET 5

Summary

The example given in https://docs.fluentvalidation.net/en/latest/advanced.html#root-context-data does not seem to work. I have a possible workaround but I am not sure if it is appropriate or will even work.

Using the example in the link above results in:

Exact error message: error CS1061: 'ValidationContext<MyViewModel>' does not contain a definition for 'ParentContext' and no accessible extension method 'ParentContext' accepting a first argument of type 'ValidationContext<MyViewModel>' could be found (are you missing a using directive or an assembly reference?)

Possible workaround(?)

RuleFor(x => x.Surname).Custom((x, context) => {
    if ((context as IValidationContext).ParentContext.RootContextData.ContainsKey("MyCustomData"))
    {
        context.AddFailure("My error message");
    }
});

[JeremySkinner]

Thanks, I’ve updated the docs, they should publish momentarily.

[JeremySkinner]

Yep, it’s the same instance used everywhere. It’s intended to be a way to share data that you can access anywhere in the validation process.

Should ParentContext be accessible at all in V10 now?

No, you shouldn’t need to use it. In 9.x you had to use context.ParentContext as context is a PropertyValidatorContext, and ParentContext is a ValidationContext<T> but in 10.0 the ValidationContext<T> Is passed in directly and we don’t use PropertyValidatorContext anymore.

There’s a section in the upgrade guide that mentions that various places now take a ValidationContext instead of a PropertyValidatorContext, I’ll try and make it clearer that this also means you don’t need to access ParentContext anymore.