Customization & Extensibility – Updated Extension Point

IValidationMessageResolver

You can implement your own message resolution strategy by inheriting:

public interface IValidationMessageResolver
{
    string? ResolveMessage(PropertyValidationInfo propertyInfo, ValidationAttribute attr);
}

By default, ValidationMessageResolver uses:

• propertyInfo.TargetModelType to locate the resource class
• Convention: PropertyName_AttributeType for message keys
• Fallback to [ErrorMessage] or default text

Custom resolvers can inject external providers, telemetry, or override formatting logic.

Register via DI:

services.AddSingleton<IValidationMessageResolver, MyCustomResolver>();

Add Custom Rules

Extend DataAnnotationsValidator with your own attributes:

public class MyCustomAttribute : ValidationAttribute
{
    // Your logic here
}