Custom validation with DbContext

CustomValidatorWithDbContext.cs

using papemk2.Entities.Db;
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Threading.Tasks;

namespace papemk2.Attributes
{
    public class CustomValidationAttribute : ValidationAttribute
    {
        public CustomValidationAttribute()
        {
        }

        protected override ValidationResult IsValid(object value, ValidationContext validationContext)
        {
            papemk2DbContext context = (papemk2DbContext) validationContext.GetService(typeof(papemk2DbContext));

            return base.IsValid(value, validationContext);
        }
    }
}