Remove ModelState errors in ASP.NET MVC

Question

Is there any way to remove model validation for some properties in a Model in ASP.Net MVC6.

I came across this post Is there a strongly-named way to remove ModelState errors in ASP.NET MVC

which suggests using, ModelBindingHelper.ClearValidationStateForModel(Type, ModelStateDictionary, IModelMetadataProvider, string).

But I am unable to find any further help on this.

Can anyone please suggest a working example of removing a model property using ClearValidationStateForModel?

What are you trying to do ? You want to remove a model validation error for few properties ? — Shyju
– Shyju, Commented Apr 1, 2016 at 16:42
Possible duplicate of Is there a strongly-named way to remove ModelState errors in ASP.NET MVC — KyleMit
– KyleMit ♦, Commented May 30, 2018 at 12:32

Shyju · Accepted Answer · 2016-04-01 18:29:31Z

6

This should remove the validation errors for the Title property of your CreatePost view model.

[HttpPost]
public ActionResult Create(CreatePost model)  
{
    if (ModelState.IsValid)
    {
      //to do : Save and return something
    }   
    ModelBindingHelper.ClearValidationStateForModel(model.GetType(),
                                              ModelState,MetadataProvider,"Title");        
    return View(model);
}

Also, ModelState.ClearValidationState will also work.

ModelState.ClearValidationState("Title");

EDIT : As per the comment, OP wants to exclude a certain property to be validated based on another property value. This should work fine.

[HttpPost]
public ActionResult Create(CreatePost model)   //CreatePost model
{
    if (model.Type == 1)
    {
        ModelBindingHelper.ClearValidationStateForModel(model.GetType(), 
                                                    ModelState, MetadataProvider, "Title");
    }
    if (ModelState.IsValid)
    {
        // to do : Do useful stuff and return something
    }
    return View(model);
}

edited Apr 1, 2016 at 18:29

answered Apr 1, 2016 at 16:53

Shyju

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5 Comments

Naveed Ahmed Over a year ago

Both of these doesn't seem to work in ASP.Net MVC 6. Below is how I am using it: [HttpPost] public ActionResult Create(CreatePost model) { //I want to skip the validation for Title, so I added this line before checking ModelState.IsValid ModelBindingHelper.ClearValidationStateForModel(model.GetType(), ModelState,MetadataProvider,"Title"); if (ModelState.IsValid) { //to do : Save and return something } return View(model); }

Shyju Over a year ago

What do you mean it does not work on MVC6 ? I just verified this in an MVC 6 project and it works fine (both dnx 451 and dnxcore50). Specifically what is not working for you ?

Naveed Ahmed Over a year ago

I have different properties in a model one of them is Type and Other is Duration, I want to skip validation of Duration if the selected type is 1 whereas I want to run the validation for all other types. In MVC5 ModelState.Remove("Duration"); before checking ModelState.IsValid was working, this doesnt seem to work in MVC 6. I also tried your suggested solution i.e. ModelState.ClearValidationState("Duration"); before checking ModelState.IsValid, but it does work the ModelState.IsValid is returned as fails. I have verified all other properties of the model have valid data.

Shyju Over a year ago

It should work ! I just verified it. See my updated answer. The code i posted works fine for me in MVC 6. Project. Put a breakpoint and see whether it is going inside your if condition.

Thomas.Benz Over a year ago

@Shyju I still use MVC 5 and I am trying to find the similar library for MVC 5. Where can I find out an open source for MVC 5? The link github.com/aspnet/Mvc/blob/… is just for MVC.Core.

Mohamad Elnaqeeb · Accepted Answer · 2022-03-25 08:21:49Z

2

For new comers use

ModelState.ClearValidationState("propertyname");
ModelState.MarkFieldValid("propertyname");

If its nested object then use objectname.propertyname.

this works on ASP.Net Core 6.0

answered Mar 25, 2022 at 8:21

Mohamad Elnaqeeb

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Comments

KyleMit · Accepted Answer · 2018-05-30 01:39:26Z

1

ModelBindingHelper is new to ASP.NET Core 2.0 / MVC6+

If you need to use against previous versions of .NET / ASP.NET, you can do the following per Simon_Weaver's answer on Is there a strongly-named way to remove ModelState errors:

Here's my solution - a RemoveFor() extension method on ModelState, modelled after MVC HTML helpers:

public static void RemoveFor<TModel>(this ModelStateDictionary modelState, 
                                     Expression<Func<TModel, object>> expression)
{
    string expressionText = ExpressionHelper.GetExpressionText(expression);

    foreach (var ms in modelState.ToArray())
    {
        if (ms.Key.StartsWith(expressionText + "."))
        {
            modelState.Remove(ms);
        }
    }
}

And here's how it's used:

if (model.CheckoutModel.ShipToBillingAddress == true) 
{
    // COPY BILLING ADDRESS --> SHIPPING ADDRESS
    ShoppingCart.ShippingAddress = ShoppingCart.BillingAddress;

    // REMOVE MODELSTATE ERRORS FOR SHIPPING ADDRESS
    ModelState.RemoveFor<SinglePageStoreModel>(x => x.CheckoutModel.ShippingAddress);
}

if (ModelState.IsValid) 
{
     // should get here now provided billing address is valid
}

answered May 30, 2018 at 1:39

KyleMit♦

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2 Comments

Dai Over a year ago

I do this, and I verified that this.ModelState.Values.All( ms => ms.Errors.Count == 0 ) however this.ModelState.IsValid == false. Why?

binco Over a year ago

@Dai you need to call MarkFieldValid() after ClearValidationState(). Otherwise the ValidationState is Unvalidated which results in ModelState.IsValid = false

Spencer Sullivan · Accepted Answer · 2020-10-22 03:03:24Z

1

I needed for validation to have an exception for a single field in the VM

In the controller, I am doing:

if ("true" == Condition)
{
    ModelState.Remove("KeyName");
}

If "KeyName" was the only error in the ModelState, it will now be true

if (ModelState.IsValid)
{   
    // ModelState.IsValid is true now
}

answered Oct 22, 2020 at 3:03

Spencer Sullivan

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