RequiredIf Conditional Validation Attribute

Question

I was looking for some advice on the best way to go about implementing a validation attribute that does the following.

Model

public class MyInputMode         


        

Answer 1

I got it to work on ASP.NET MVC 5

I saw many people interested in and suffering from this code and i know it's really confusing and disrupting for the first time.

Notes

• worked on MVC 5 on both server and client side :D
• I didn't install "ExpressiveAnnotations" library at all.
• I'm taking about the Original code from "@Dan Hunex", Find him above

Tips To Fix This Error

"The type System.Web.Mvc.RequiredAttributeAdapter must have a public constructor which accepts three parameters of types System.Web.Mvc.ModelMetadata, System.Web.Mvc.ControllerContext, and ExpressiveAnnotations.Attributes.RequiredIfAttribute Parameter name: adapterType"

Tip #1: make sure that you're inheriting from 'ValidationAttribute' not from 'RequiredAttribute'

 public class RequiredIfAttribute : ValidationAttribute, IClientValidatable { ...}

Tip #2: OR remove this entire line from 'Global.asax', It is not needed at all in the newer version of the code (after edit by @Dan_Hunex), and yes this line was a must in the old version ...

DataAnnotationsModelValidatorProvider.RegisterAdapter(typeof(RequiredIfAttribute), typeof(RequiredAttributeAdapter));

Tips To Get The Javascript Code Part Work

1- put the code in a new js file (ex:requiredIfValidator.js)

2- warp the code inside a $(document).ready(function(){........});

3- include our js file after including the JQuery validation libraries, So it look like this now :

@Scripts.Render("~/bundles/jqueryval")

4- Edit the C# code

from

rule.ValidationParameters["dependentproperty"] = (context as ViewContext).ViewData.TemplateInfo.GetFullHtmlFieldId(PropertyName);

to

rule.ValidationParameters["dependentproperty"] = PropertyName;

and from

if (dependentValue.ToString() == DesiredValue.ToString())

to

if (dependentValue != null && dependentValue.ToString() == DesiredValue.ToString())

My Entire Code Up and Running

Global.asax

Nothing to add here, keep it clean

requiredIfValidator.js

create this file in ~/content or in ~/scripts folder

    $.validator.unobtrusive.adapters.add('requiredif', ['dependentproperty', 'desiredvalue'], function (options)
{
    options.rules['requiredif'] = options.params;
    options.messages['requiredif'] = options.message;
});


$(document).ready(function ()
{

    $.validator.addMethod('requiredif', function (value, element, parameters) {
        var desiredvalue = parameters.desiredvalue;
        desiredvalue = (desiredvalue == null ? '' : desiredvalue).toString();
        var controlType = $("input[id$='" + parameters.dependentproperty + "']").attr("type");
        var actualvalue = {}
        if (controlType == "checkbox" || controlType == "radio") {
            var control = $("input[id$='" + parameters.dependentproperty + "']:checked");
            actualvalue = control.val();
        } else {
            actualvalue = $("#" + parameters.dependentproperty).val();
        }
        if ($.trim(desiredvalue).toLowerCase() === $.trim(actualvalue).toLocaleLowerCase()) {
            var isValid = $.validator.methods.required.call(this, value, element, parameters);
            return isValid;
        }
        return true;
    });
});

_Layout.cshtml or the View

@Scripts.Render("~/bundles/jqueryval")

RequiredIfAttribute.cs Class

create it some where in your project, For example in ~/models/customValidation/

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

namespace Your_Project_Name.Models.CustomValidation
{
    public class RequiredIfAttribute : ValidationAttribute, IClientValidatable
    {
        private String PropertyName { get; set; }
        private Object DesiredValue { get; set; }
        private readonly RequiredAttribute _innerAttribute;

        public RequiredIfAttribute(String propertyName, Object desiredvalue)
        {
            PropertyName = propertyName;
            DesiredValue = desiredvalue;
            _innerAttribute = new RequiredAttribute();
        }

        protected override ValidationResult IsValid(object value, ValidationContext context)
        {
            var dependentValue = context.ObjectInstance.GetType().GetProperty(PropertyName).GetValue(context.ObjectInstance, null);

            if (dependentValue != null && dependentValue.ToString() == DesiredValue.ToString())
            {
                if (!_innerAttribute.IsValid(value))
                {
                    return new ValidationResult(FormatErrorMessage(context.DisplayName), new[] { context.MemberName });
                }
            }
            return ValidationResult.Success;
        }

        public IEnumerable GetClientValidationRules(ModelMetadata metadata, ControllerContext context)
        {
            var rule = new ModelClientValidationRule
            {
                ErrorMessage = ErrorMessageString,
                ValidationType = "requiredif",
            };
            rule.ValidationParameters["dependentproperty"] = PropertyName;
            rule.ValidationParameters["desiredvalue"] = DesiredValue is bool ? DesiredValue.ToString().ToLower() : DesiredValue;

            yield return rule;
        }
    }
}

The Model

    using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Web;
using Your_Project_Name.Models.CustomValidation;

namespace Your_Project_Name.Models.ViewModels
{

    public class CreateOpenActivity
    {
        public Nullable ORG_BY_CD { get; set; }

        [RequiredIf("ORG_BY_CD", "5", ErrorMessage = "Coordinator ID is required")] // This means: IF 'ORG_BY_CD' is equal 5 (for the example)  > make 'COR_CI_ID_NUM' required and apply its all validation / data annotations
        [RegularExpression("[0-9]+", ErrorMessage = "Enter Numbers Only")]
        [MaxLength(9, ErrorMessage = "Enter a valid ID Number")]
        [MinLength(9, ErrorMessage = "Enter a valid ID Number")]
        public string COR_CI_ID_NUM { get; set; }
    }
}

The View

Nothing to note here actually ...

    @model Your_Project_Name.Models.ViewModels.CreateOpenActivity
@{
    ViewBag.Title = "Testing";
}

@using (Html.BeginForm()) 
{
    @Html.AntiForgeryToken()

    

        
CreateOpenActivity
        

        @Html.ValidationSummary(true, "", new { @class = "text-danger" })

        

            @Html.LabelFor(model => model.ORG_BY_CD, htmlAttributes: new { @class = "control-label col-md-2" })
            

                @Html.EditorFor(model => model.ORG_BY_CD, new { htmlAttributes = new { @class = "form-control" } })
                @Html.ValidationMessageFor(model => model.ORG_BY_CD, "", new { @class = "text-danger" })
            
        

        

            @Html.LabelFor(model => model.COR_CI_ID_NUM, htmlAttributes: new { @class = "control-label col-md-2" })
            

                @Html.EditorFor(model => model.COR_CI_ID_NUM, new { htmlAttributes = new { @class = "form-control" } })
                @Html.ValidationMessageFor(model => model.COR_CI_ID_NUM, "", new { @class = "text-danger" })
            
        

        

            

                
            
        
    
}

I may upload a project sample for this later ...

Hope this was helpful

Thank You