Remove ModelState errors in ASP.NET MVC

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?

Answers:

Thank you for visiting the Q&A section on Magenaut. Please note that all the answers may not help you solve the issue immediately. So please treat them as advisements. If you found the post helpful (or not), leave a comment & I’ll get back to you as soon as possible.

Method 1

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);
}

Method 2

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
}

Method 3

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
}

Method 4

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

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0