Unrequired property keeps getting data-val-required attribute - asp.net-mvc

Question

This is the model with it's validation:
[MetadataType(typeof(TagValidation))]
public partial class Tag
{
}
public class TagValidation
{
[Editable(false)]
[HiddenInput(DisplayValue = false)]
public int TagId { get; set; }
[Required]
[StringLength(20)]
[DataType(DataType.Text)]
public string Name { get; set; }
//...
}
Here is the view:
<h2>Create</h2>
<script src="#Url.Content("~/Scripts/jquery.validate.min.js")" type="text/javascript"></script>
<script src="#Url.Content("~/Scripts/jquery.validate.unobtrusive.min.js")" type="text/javascript"></script>
#using (Html.BeginForm()) {
#Html.ValidationSummary(true)
<fieldset>
<legend>Tag</legend>
<div>#Html.EditorForModel()</div>
<p>
<input type="submit" value="Create" />
</p>
</fieldset>
}
<div>
#Html.ActionLink("Back to List", "Index")
</div>
And here is what get's renderd:
<form action="/Tag/Create" method="post">
<fieldset>
<legend>Tag</legend>
<div><input data-val="true" data-val-number="The field TagId must be a number." data-val-required="The TagId field is required." id="TagId" name="TagId" type="hidden" value="" />
<div class="editor-label"><label for="Name">Name</label></div>
<div class="editor-field"><input class="text-box single-line" data-val="true" data-val-length="The field Name must be a string with a maximum length of 20." data-val-length-max="20" data-val-required="The Name field is required." id="Name" name="Name" type="text" value="" /> <span class="field-validation-valid" data-valmsg-for="Name" data-valmsg-replace="true"></span></div>
...
</fieldset>
</form>
The problem is that TagId validation gets generated althoug thare is no Required attribute set on TagId property. Because of that I can't even pass the client-side validation in order to create new Tag in db.
What am I missing?

Answer 1

I found the answer. Just add this to Application_Start:
DataAnnotationsModelValidatorProvider.AddImplicitRequiredAttributeForValueTypes = false;

Answer 2

Make the view-model value-types nullable. Then they won't be Required by default.
Note also if you put the attribute 'required="false"' in html 5 (if you set html 5 in your doctype meta data), it will see "required" and make it required. You can use dojo-data-props="required:false".

Answer 3

frennky's solution only removed data-val-required but in my case I still had data-val-number and data-val
I had to add the two lines below to Application_Start to get rid of everything.
ModelValidatorProviders.Providers.Clear();
ModelValidatorProviders.Providers.Add(new DataAnnotationsModelValidatorProvider());

Answer 4

The problem is that the value of the hidden field is empty. This shouldn't happen if you use integer type. I suppose that the TagId property is defined as a nullable type in the Tag class. So either assign it a value before rendering the view or use an integer type:
[MetadataType(typeof(TagValidation))]
public partial class Tag
{
public int TagId { get; set; }
public string Name { get; set; }
}
so that the generated hidden field looks like this:
<input
data-val="true"
data-val-number="The field TagId must be a number."
data-val-required="The TagId field is required."
id="TagId"
name="TagId"
type="hidden"
value="0"
/>
Also normally client side validation shouldn't be triggered for this hidden field.

Answer 5

jquery validate target cheking "disabled" html attribute.
$(function () {
$("#TagId").attr("disabled", "disabled")
});
or use Nullable.
hope this code!

Answer 6

With MVC4 you can also use this:
#{ Html.EnableClientValidation(false); }
#Html.EditorForModel()
#{ Html.EnableClientValidation(true); }

Answer 7

Make your Model or View-Model property value-types "nullabel". This will solve your problem.One important thing that remove "required" attribute from your tag otherwise it will take i "required"
Example:-
public class ViewModle
{
public int? foo{get;set;}
}
Here in example foo is integer nullable type, this will no longer required in mvc.
Hope this will help you.

Answer 8

I had the unfortunate experience that my model attributes were suddenly required causing my web APIs to return 400 errors when attributes were missing from web requests.
I found out this was caused by an accidental change of the "Nullable" setting in the project (Project properties -> Build -> Nullable: Enable"
After changing Nullable to Disable, all was good again.
I found a more detailed explanation of the issue here:
https://learn.microsoft.com/en-us/dotnet/csharp/nullable-references#nullable-contexts