Enhance Blazor's form validation capabilities to provide a more complete and flexible developer experience across all rendering modes. This epic focuses on three key areas that will improve how developers build and validate forms in Blazor applications.

Objectives

This work aims to modernize Blazor's validation infrastructure to support modern web application patterns while maintaining consistency with ASP.NET Core's validation ecosystem.

Key Areas:

1. Client-Side Validation without Interactivity - Enable data annotation-based client validation for statically rendered forms without requiring Blazor Server circuits or WebAssembly interactivity

2. Async Validation Support - Extend the EditContext API to support asynchronous validation scenarios, including tracking pending validation tasks and providing appropriate UI feedback states

3. Localization for Validation Messages - Improve support for localizing data annotation attributes and validation messages in Blazor components, particularly for non-resx scenarios

Success Criteria

• Developers can create static server-rendered forms with client-side validation similar to MVC/Razor Pages
• Forms can perform async validation operations (e.g., remote API calls) with proper pending state indicators
• Validation messages can be localized using flexible localization services beyond traditional resource files