CODEWITHSUNDEEP
asp.net-mvc
Kristianne Nerona
Kristianne Nerona

Reputation: 755

Custom validation attribute's set error message not showing as predicted

I have a custom validation attribute:

public class RequireIfPropertyIsFalseAttribute : ValidationAttribute
    {
        private string basisProperty { get; set; }
        public RequireIfPropertyIsFalseAttribute(string basisProperty)
        {
            this.basisProperty = basisProperty;
        }

        protected override ValidationResult IsValid(object value, ValidationContext validationContext)
        {
            var basisProp = validationContext.ObjectType.GetProperty(basisProperty);
            var isFalse = !(bool)basisProp.GetValue(validationContext.ObjectInstance, null);

            if (isFalse)
            {
                if (value == null || (value.GetType() == typeof(string) && string.IsNullOrEmpty(((string)value).Trim())))
                        return new ValidationResult(this.ErrorMessage);
            }

            return ValidationResult.Success;
        }
    }

I use it for both Model properties:

public bool NoAgeProvided { get; set; }
[RequireIfPropertyIsFalse(nameof(NoAgeProvided), ErrorMessage = "This is required")]
[Display(Name = "Age")]
public int Age { get; set; }

public bool NoNameProvided { get; set; }
[RequireIfPropertyIsFalse(nameof(NoNameProvided), ErrorMessage = "This is required")]
[Display(Name = "Name")]
public string Name { get; set; }

Upon validation, the Name validation message shows "This is required". However, for the Age property, "The Age field is required" is displaying on the validation message. What am I doing wrong? How can I display the set ErrorMessage?

Upvotes: 2

Views: 2558

Answers (1)

user3559349
user3559349

Reputation:

Because property Age is typeof int, it is always required (an int cannot be null) and if you leave the textbox empty, a null value is submitted and the Required validation is executed first and that error message is displayed.

Change you property to be nullable

public int? Age { get; set; }

Note that it works for your Name property because its string which is nullable by default.

As a side note, you should consider implementing IClientValidatable so that you can get client side validation as well. Refer The Complete Guide To Validation In ASP.NET MVC 3 - Part 2.

Upvotes: 1

Related Questions