Can't use RuleSets or Selectors with Field Validation

[SamCodes96]

It would be nice to be able to have custom Selectors and RuleSets apply to individual field validation not just OnSubmit validation.

Say I have a field with two rules in the Validator:

A: Simple validation like a length check
B: Database validation

There is currently no way to prevent Rule B from running whenever the field changes.

[pwelter34]

Have any ideas about how to make that work? Seems like a good feature.

[xfunc-tim-schneider]

I ran into this same issue — I have a form with two validation profiles:

• Default rules (format/length) — should run on field change (blur)
• Submit RuleSet (required fields) — should only run on form submit

Currently, if I set RuleSets="@(["submit"])" on FluentValidator, both the submit rules AND default rules run on every field change. There's no way to say "only validate default rules on blur, add submit rules on form submission."

My workaround was to build a supplementary validation layer that runs its own Validator.ValidateAsync() with explicit IncludeRuleSets() in the OnInvalidSubmit handler, and manages a separate ValidationMessageStore for the submit-only errors. It works but it's a significant amount of infrastructure that ideally the library would handle.

One possible API could be a separate FieldChangeRuleSets parameter:

<FluentValidator RuleSets="@(["submit"])"
                 FieldChangeRuleSets="@(["default"])" />

Where RuleSets controls what runs on OnValidationRequested (form submit), and FieldChangeRuleSets controls what runs on OnFieldChanged (blur/keystroke). If FieldChangeRuleSets is not set, it falls back to RuleSets for backwards compatibility.

I've also opened #95 about PathResolver.FindField returning null for nullable nested properties — a related but separate limitation. Together, these two issues drove most of the supplementary validation infrastructure I had to build.