jQuery validation for nullable data type

Question

I am not sure why the jquery validation fires when the property is nullable int? and not marked with any data annotation attribute. Its asp.net MVC 4 application

public class MyViewModel{

   public int? ResourceId { get; set; }

}

MyView.cshtml

@model MyViewModel

@Html.DropDownListFor(m => m.ResourceId, 
     ((IEnumerable<SelectListItem>)ViewData["resourceLookup"]),"--Select--")

Generated HTML

<select data-val="true" data-val-number="The field ResourceId must be a number." 
           id="ResourceId" name="ResourceId">
  <option value="">--Select--</option>
  <option value="1">Type 1</option>
</select>

This select box is an optional one. User may ignore it. But when they ignore i am getting error message The field ResourceId must be a number.

In Global.asax.cs, I tried setting AddImplicitRequiredAttributeForValueTypes property to prevent adding the data-* attributes to unwanted fields. But as the name says it prevents only adding data-required-* attributes.

protected void Application_Start()
{
 DataAnnotationsModelValidatorProvider.AddImplicitRequiredAttributeForValueTypes=false;
}

How can I prevent the data type checking attribute(data-val-number) here?

EDIT:

Tried setting DataType also no use, still having same issue. It looks like this will not be applied for <select> and may be applied only for <input> and set type="text"

    [DataType(DataType.Text)]
    public int? ResourceId { get; set; }

Answer 1

I had the same problem and just switched off client-side validation for my dropdown list. You can deactivate validation for this field by setting data-val = "false":

@Html.DropDownListFor(m => m.ResourceId, 
 ((IEnumerable<SelectListItem>)ViewData["resourceLookup"]),"--Select--", new { @data_val = "false" })

This will not remove the data-val-number attribute but prevent the validation.

Answer 2

When you set the ViewData["resourceLookup"] try adding -1 for the option Select .

Thanks!