Custom validation error message if user puts a non-numeric string in an int field

Question

This question has to have been asked before, but I think the search terms are too generic for me to find the answer I'm looking for, so I'll ask it again.

I have a model with an int property, and a range annotation.

If the user enters something other than an int, the validation message responds with The value '<bad data>' is not valid for '<property name>'... which is great, but I want to provide a bit more feedback, i.e., Expecting an integer value in this field..

Since this validation fails before the other validators take a look, I don't know how (or if it's possible) to override the default validator message for this.

What are my options?

per request, I am posting the code, but there's not a lot to it:

[Range(0,65535, ErrorMessage="Port must be between 0 and 65535.")] 
public int Port { get; set; }

There is validation that occurs before it reaches the RangeAttribute. I want to replace the default message with one of my own choosing.

Answer 1

If you're using standard annotations, you should be able to override the error message with something like this:

[MyAnnotation(...., ErrorMessage = "My error message")]
public int myInt { get; set; }

Or do you actually want to append to the default error message instead of replacing it (not clear in question)?

Update: Misread -- suggest this as the answer: How to change the ErrorMessage for int model validation in ASP.NET MVC? or better yet How to change 'data-val-number' message validation in MVC while it is generated by @Html helper

Answer 2

You can also inherit IValidatableObject in your model class. You can write down your required logic in the Validate method. Please find sample code below.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.ComponentModel.DataAnnotations;

namespace MvcApplication1.Models
{
    public class Alok : IValidatableObject
    {
        [Display(Name = "Property1")]
        [Required(AllowEmptyStrings = false, ErrorMessage = "Property1 is required.")]
        public int Property1 { get; set; }

        [Display(Name = "Property2")]
        [Required(AllowEmptyStrings = false, ErrorMessage = "Property2 is required.")]
        public int Property2 { get; set; }

        public IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
        {
            if (Property1 < Property2)
            {
                yield return new ValidationResult("Property 1 can't be less than Property 2.");
            }
        }
    }
}