Conditional Validation for nested object with parent condition

Question

I have the following classes:

class A {
    [Required]
    public string Status { get; set; }
    public B b_instance { get; set; }
}

class B {
    **[RequiredIf("A.Status == 'Active'")**
    public string x { get; set; }
}

As above, I want class B has a validation with the condition: A.Status = 'Active' then class B has [Required] x, otherwise b_instance.x is not required.

Can you try to add validationb in razor? If(Status == 'Active') with validation else without ? — mike, Jun 08 '21 at 08:27
Does [this](https://stackoverflow.com/questions/7390902/requiredif-conditional-validation-attribute) help? — Izzy, Jun 08 '21 at 08:29
Or [this](https://stackoverflow.com/questions/20642328/how-to-put-conditional-required-attribute-into-class-property-to-work-with-web-a)? — Peter Csala, Jun 08 '21 at 08:50
@Izzy That method could help somehow but I need the way for nested class get access to parent property, that's the point — Tien Dang, Jun 08 '21 at 08:52

mike · Answer 1 · 2021-06-08T09:32:20.143

If you use MVC you coud add extra validation in razor view :


@if (Model.Status == "Active")
{
    <input class="form-control" asp-for="..." required="required" />
}
else
{
    <input class="form-control" asp-for="..." />
}

If like you mentioned you need a solution for BE side you can try something with custom Validation Attribute :


 public class A
 {
      [Required]
      public string Status { get; set; }
      public StatusEnum StatusEnum { get; set; }
      public B b_instance { get; set; }
    }

    public enum StatusEnum
    {
        Active = 1,
        Deactivated = 2,
    }

    public class B : A 
    {
        [RequiredIf("Status", StatusEnum.Active , ErrorMessage = "...")]
        public string x { get; set; }
    }

    public class RequiredIfAttribute : ValidationAttribute
    {
        public string PropertyName { get; set; }
        public object Value { get; set; }

        public RequiredIfAttribute(string propertyName, object value, string errorMessage = "")
        {
            PropertyName = propertyName;
            ErrorMessage = errorMessage;
            Value = value;
        }

        protected override ValidationResult IsValid(object value, ValidationContext validationContext)
        {
            var instance = validationContext.ObjectInstance;
            var type = instance.GetType();
            var propertyValue = type.GetProperty(PropertyName).GetValue(instance, null);
            if (propertyValue .ToString() == Value.ToString() && value == null)
            {
                return new ValidationResult(ErrorMessage);
            }
            return ValidationResult.Success;
        }
    }

With this solution, I dont think we have a good way to handle this issue. Thank anyway. I decide to split it into piece for each case. — Tien Dang, Jun 09 '21 at 06:20

Conditional Validation for nested object with parent condition

1 Answers1