Add multiple validations to a single property

[alexmartinezm]

Is your feature request related to a problem? Please describe.
Actually, if you try to add two validations to the same property, eg Password, in the ValidationContext you would do it like this:

[…]
this.ValidationRule(
     vm => vm.Password,
     password => !string.IsNullOrEmpty(password),
     "Password is required.");

this.ValidationRule(
     vm => vm.Password,
     password => password.Length > 5,
     "Password minimum length is 5.");
[…]

And from the View you would bind to the Password property like this:

[…]
this.BindValidation(ViewModel, vm => vm.Password, view => view.PasswordErrorMessage.Text)
    .DisposeWith(disposables);
[…]

The problem by doing this is that from the ValidationBindings, used by the ViewForExtensions, it looks up only for the first or default validation rule (see ResolveFor methods in ValidationContextExtensions).

Describe the solution you'd like
Add support for multiple validations in the same property since it's supported in the ValidationContext side.

Describe suggestions on how to achieve the feature
Basically, if more than one property matches the query in the ResolveFor method then unless the Formatter has been provided, it should throw a custom exception like MultipleValidationNotSupportedException.

On the other side, we should provide Mixins to give support for multiple validation scenarios.

[worldbeater]

On the other side, we should provide Mixins to give support for multiple validation scenarios.

I'd prefer this option over throwing exceptions ✨

[lock]

This thread has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.