ASP.NET Core custom validation attribute localization

Question

I\'m trying to implement localization in a custom validation attribute in asp.net core 1.0. This is my simplified viewmodel:

public class EditPasswordViewMod         


        

Answer 1

Implement an adapter for localization:

public class RequiredIfAttributeAdapter : AttributeAdapterBase
{
    public RequiredIfAttributeAdapter(RequiredIfAttribute attribute, IStringLocalizer stringLocalizer) : base(attribute, stringLocalizer) {}

    public override void AddValidation(ClientModelValidationContext context) {}

    public override string GetErrorMessage(ModelValidationContextBase validationContext)
    {
        return GetErrorMessage(validationContext.ModelMetadata, validationContext.ModelMetadata.GetDisplayName());
    }
}

Implement a provider for the adapter(s):

public class CustomValidationAttributeAdapterProvider : IValidationAttributeAdapterProvider
{
    private readonly IValidationAttributeAdapterProvider _baseProvider = new ValidationAttributeAdapterProvider();

    public IAttributeAdapter GetAttributeAdapter(ValidationAttribute attribute, IStringLocalizer stringLocalizer)
    {
        if (attribute is RequiredIfAttribute)
            return new RequiredIfAttributeAdapter(attribute as RequiredIfAttribute, stringLocalizer);
        else
            return _baseProvider.GetAttributeAdapter(attribute, stringLocalizer);
    }
}

Register the provider in Startup.cs:

services.AddSingleton();

Credits to this blog: https://blogs.msdn.microsoft.com/mvpawardprogram/2017/01/03/asp-net-core-mvc/