Disable Required validation attribute under certain circumstances

Question

I was wondering if it is possible to disable the Required validation attribute in certain controller actions  I am wondering this because on one of my edit forms I do not require the user to enter values for fields that they have already specified previously  However I then implement logic that when they enter a value it uses some special logic to update the model  such as hashing a value etc   Any sugestions on how to get around this problem   EDIT  And yes client validation is a problem here to  as it will not allow them to submit the form without entering a value

User · Answer

Yes it is possible to disable Required Attribute. Create your own custom class attribute (sample code called ChangeableRequired) to extent from RequiredAtribute and add a Disabled Property and override the IsValid method to check if it is disbaled. Use reflection to set the disabled poperty, like so:

Custom Attribute:

namespace System.ComponentModel.DataAnnotations
{
    public class ChangeableRequired : RequiredAttribute
    {
       public bool Disabled { get; set; }

       public override bool IsValid(object value)
       {
          if (Disabled)
          {
            return true;
          }

          return base.IsValid(value);
       }
    }
}

Update you property to use your new custom Attribute:

 class Forex
 {
 ....
    [ChangeableRequired]
    public decimal? ExchangeRate {get;set;}
 ....
 }

where you need to disable the property use reflection to set it:

Forex forex = new Forex();
// Get Property Descriptor from instance with the Property name
PropertyDescriptor descriptor = TypeDescriptor.GetProperties(forex.GetType())["ExchangeRate"];
//Search for Attribute
ChangeableRequired attrib =  (ChangeableRequired)descriptor.Attributes[typeof(ChangeableRequired)];

// Set Attribute to true to Disable
attrib.Disabled = true;

This feels nice and clean?

NB: The validation above will be disabled while your object instance is alive\active...

User · Answer

In my case the same Model was used in many pages for re-usability purposes  So what i did was i have created a custom attribute which checks for exclusions  public class ValidateAttribute   ActionFilterAttribute       public string Exclude   get  set        public string Base   get  set        public override void OnActionExecuting HttpActionContext actionContext                if   string IsNullOrWhiteSpace this Exclude                         string   excludes   this Exclude Split                   foreach  var exclude in excludes                                actionContext ModelState Remove Base         exclude                                   if  actionContext ModelState IsValid    false                        var mediaType   new MediaTypeHeaderValue  application json                var error   actionContext ModelState               actionContext Response   actionContext Request CreateResponse HttpStatusCode OK  error Keys  mediaType                        and in your controller   Validate Base   person  Exclude   Age Name        public async Task lt IHttpActionResult gt  Save User person                       do something                     Say the Model is   public class User       public int Id   get  set         Required      public string Name   get  set         Range 18 99       public string Age   get  set         MaxLength 250       public string Address   get  set

User · Answer

I know this question has been answered a long time ago and the accepted answer will actually do the work  But there s one thing that bothers me  having to copy 2 models only to disable a validation   Here s my suggestion   public class InsertModel        Display           public virtual string ID   get  set            Other properties    public class UpdateModel   InsertModel        Required      public override string ID               get   return base ID            set   base ID   value              This way  you don t have to bother with client server side validations  the framework will behave the way it s supposed to  Also  if you define a  Display  attribute on the base class  you don t have to redefine it in your UpdateModel   And you can still use these classes the same way    HttpPost  public ActionResult Update UpdateModel model                HttpPost  public ActionResult Insert InsertModel model

User · Answer

Personally I would tend to use the approach Darin Dimitrov showed in his solution   This frees you up to be able to use the data annotation approach with validation AND have separate data attributes on each ViewModel corresponding to the task at hand   To minimize the amount of work for copying between model and viewmodel you should look at AutoMapper or ValueInjecter  Both have their individual strong points  so check them both    Another possible approach for you would be to derive your viewmodel or model from IValidatableObject  This gives you the option to implement a function Validate   In validate you can return either a List of ValidationResult elements or issue a yield return for each problem you detect in validation    The ValidationResult consists of an error message and a list of strings with the fieldnames  The error messages will be shown at a location near the input field s    public IEnumerable lt ValidationResult gt  Validate ValidationContext validationContext      if  NumberField  lt  0           yield return new ValidationResult            Don t input a negative number            new      NumberField              if  NumberField  gt  100           yield return new ValidationResult            Don t input a number  gt  100            new      NumberField              yield break

User · Answer

this was someone else s answer in the comments   but it should be a real answer       SomeValue   removeAttr  data-val-required    tested on MVC 6 with a field having the  Required  attribute  answer stolen from https   stackoverflow com users 73382 rob above

User · Answer

Client side For disabling validation for a form  multiple options based on my research is given below  One of them would would hopefully work for you   Option 1  I prefer this  and this works perfectly for me    function             fn turnOffValidation   function  form            var settings   form validate   settings           for  var ruleIndex in settings rules                delete settings rules ruleIndex                       jQuery      and invoking it like      btn   click function            this  turnOffValidation jQuery   myForm           Option 2     your selector here   data  val   false      form   removeData  validator       form   removeData  unobtrusiveValidation      validator unobtrusive parse  form      Option 3  var settings     data     myForm   get 0    validator   settings  settings ignore     input     Option 4      form   get 0  submit     jQuery   createForm   unbind  submit   submit      Option 5     input selector   each function            this  rules  remove          Server Side   Create an attribute and mark your action method with that attribute  Customize this to adapt to your specific needs    AttributeUsage AttributeTargets All   public class IgnoreValidationAttribute   ActionFilterAttribute       public override void OnActionExecuting ActionExecutingContext filterContext                var modelState   filterContext Controller ViewData ModelState           foreach  var modelValue in modelState Values                        modelValue Errors Clear                        A better approach has been described here Enable Disable mvc server side validation dynamically

User · Answer

This problem can be easily solved by using view models  View models are classes that are specifically tailored to the needs of a given view  So for example in your case you could have the following view models   public UpdateViewView        Required      public string Id   get  set             some other properties    public class InsertViewModel       public string Id   get  set             some other properties     which will be used in their corresponding controller actions    HttpPost  public ActionResult Update UpdateViewView model                HttpPost  public ActionResult Insert InsertViewModel model

User · Answer

As of MVC 5 this can be easily achieved by adding this in your global asax   DataAnnotationsModelValidatorProvider AddImplicitRequiredAttributeForValueTypes   false

User · Answer

I was having this problem when I creating a Edit View for my  Model and I want to update just one field    My solution for a simplest way is put the two field  using      lt    Html HiddenFor model   gt  model ID    gt    lt    Html HiddenFor model   gt  model Name   gt    lt    Html HiddenFor model   gt  model Content   gt    lt    Html TextAreaFor model   gt  model Comments   gt    Comments is the field that I only update in Edit View  that not have Required Attribute   ASP NET MVC 3 Entity

User · Answer

What  Darin said is what I would recommend as well  However I would add to it  and in response to one of the comments  that you can in fact also use this method for primitive types like bit  bool  even structures like Guid by simply making them nullable  Once you do this  the Required attribute functions as expected   public UpdateViewView        Required      public Guid  Id   get  set         Required      public string Name   get  set         Required      public int  Age   get  set         Required      public bool  IsApproved   get  set              some other properties

User · Answer

The cleanest way here I believe is going to disable your client side validation and on the server side you will need to    ModelState  SomeField   Errors Clear    in your controller or create an action filter to remove errors before the controller code is executed  Add ModelState AddModelError from your controller code when you detect a violation of your detected issues    Seems even a custom view model here wont solve the problem because the number of those  pre answered  fields could vary  If they dont then a custom view model may indeed be the easiest way  but using the above technique you can get around your validations issues

User · Answer

If you just want to disable validation for a single field in client side then you can override the validation attributes as follows   Html TextBoxFor model   gt  model SomeValue                   new Dictionary lt string  object gt       quot data-val quot   false

User · Answer

If you don t want to use another ViewModel you can disable client validations on the view and also remove the validations on the server for those properties you want to ignore  Please check this answer for a deeper explanation https   stackoverflow com a 15248790 1128216

User · Answer

AFAIK you can not remove attribute at runtime  but only change their values  ie  readonly true false  look here for something similar   As another way of doing what you want without messing with attributes I will go with a ViewModel for your specific action so you can insert all the logic without breaking the logic needed by other controllers  If you try to obtain some sort of wizard  a multi steps form  you can instead serialize the already compiled fields and with TempData bring them along your steps   for help in serialize deserialize you can use MVC futures

User · Answer

I was looking for a solution where I can use the same model for an insert and update in web api  In my situation is this always a body content  The  Requiered  attributes must be skipped if it is an update method  In my solution  you place an attribute  IgnoreRequiredValidations  above the method  This is as follows   public class WebServiceController   ApiController        HttpPost      public IHttpActionResult Insert SameModel model                                HttpPut       IgnoreRequiredValidations      public IHttpActionResult Update SameModel model                                     What else needs to be done  An own BodyModelValidator must becreated and added at the startup   This is in the HttpConfiguration and looks like this  config Services Replace typeof IBodyModelValidator   new IgnoreRequiredOrDefaultBodyModelValidator      using Owin  using your namespace Web Http Validation    assembly  OwinStartup typeof your namespace Startup     namespace your namespace       public class Startup               public void Configuration IAppBuilder app                        Configuration app  new HttpConfiguration                        public void Configuration IAppBuilder app  HttpConfiguration config                        config Services Replace typeof IBodyModelValidator   new IgnoreRequiredOrDefaultBodyModelValidator                              My own BodyModelValidator is derived from the DefaultBodyModelValidator  And i figure out that i had to override the  ShallowValidate  methode  In this override i filter the requierd model validators  And now the IgnoreRequiredOrDefaultBodyModelValidator class and the IgnoreRequiredValidations attributte class   using System  using System Collections Concurrent  using System Collections Generic  using System Linq  using System Reflection  using System Web Http Controllers  using System Web Http Metadata  using System Web Http Validation   namespace your namespace Web Http Validation       public class IgnoreRequiredOrDefaultBodyModelValidator   DefaultBodyModelValidator               private static ConcurrentDictionary lt HttpActionBinding  bool gt   ignoreRequiredValidationByActionBindingCache           static IgnoreRequiredOrDefaultBodyModelValidator                          ignoreRequiredValidationByActionBindingCache   new ConcurrentDictionary lt HttpActionBinding  bool gt                        protected override bool ShallowValidate ModelMetadata metadata  BodyModelValidatorContext validationContext  object container  IEnumerable lt ModelValidator gt  validators                        var actionContext   validationContext ActionContext               if  RequiredValidationsIsIgnored actionContext ActionDescriptor ActionBinding                   validators   validators Where v   gt   v IsRequired                          return base ShallowValidate metadata  validationContext  container  validators                       region RequiredValidationsIsIgnored         private bool RequiredValidationsIsIgnored HttpActionBinding actionBinding                        bool ignore               if    ignoreRequiredValidationByActionBindingCache TryGetValue actionBinding  out ignore                    ignoreRequiredValidationByActionBindingCache TryAdd actionBinding  ignore   RequiredValidationsIsIgnored actionBinding ActionDescriptor as ReflectedHttpActionDescriptor                 return ignore                     private bool RequiredValidationsIsIgnored ReflectedHttpActionDescriptor actionDescriptor                        if  actionDescriptor    null                  return false               return actionDescriptor MethodInfo GetCustomAttribute lt IgnoreRequiredValidationsAttribute gt  false     null                      endregion             AttributeUsage AttributeTargets Method  Inherited   true       public class IgnoreRequiredValidationsAttribute   Attribute                  Sources    Using string debug   new StackTrace   ToString   to find out who is handeling the model validation  https   docs microsoft com en-us aspnet web-api overview advanced configuring-aspnet-web-api to know how set my own validator  https   github com ASP-NET-MVC aspnetwebstack blob master src System Web Http Validation DefaultBodyModelValidator cs to figure out what this validator is doing  https   github com Microsoft referencesource blob master System Web ModelBinding DataAnnotationsModelValidator cs to figure out why the IsRequired property is set on true  Here you can also find the original Attribute as a property

User · Answer

You can remove all validation off a property with the following in your controller action   ModelState Remove lt ViewModel gt  x   gt  x SomeProperty      Ian s comment regarding MVC5   The following is still possible  ModelState Remove  PropertyNameInModel      Bit annoying that you lose the static typing with the updated API  You could achieve something similar to the old way by creating an instance of HTML helper and using NameExtensions Methods

[c#] Disable Required validation attribute under certain circumstances

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