Unobtrusive javascript adding data to #Html.HiddenFor - asp.net-mvc

Question

I have a hidden field on a form that is created in Razor using the #Html.HiddenFor helper:
#Html.HiddenFor(model => model.BidID, new { id="bidItemID" })
My View model looks like this:
public class BidEditVM
{
[Display(Name = "Bid ID")]
public int BidID { get; set; }
[StringLength(51)]
[Display(Name = "Customer Name")]
public string CustomerName { get; set; }
[StringLength(75)]
[Display(Name = "Bid Name")]
public string BidName { get; set; }
[Display(Name = "Amount")]
public decimal Amount { get; set; }
[Display(Name = "Time")]
public DateTime BidTime { get; set; }
}
When the HTML is rendered, unobtrusive javascript adds it's stuff to the hidden input field even though it will never require validation:
<input id="bidItemID" type="hidden" value="5198" name="BidID" data-val-required="The Bid ID field is required." data-val-number="The field Bid ID must be a number." data-val="true">
What's odder is that the message and validation it adds aren't even part of the view model for this partial view. The view looks like this:
#model AuctionAdmin.Models.ViewModels.BidEditVM
#using (Ajax.BeginForm("UpdateBid", new AjaxOptions { HttpMethod = "Post", UpdateTargetId = "modalBidInfo" }))
{
#Html.ValidationSummary(true)
#Html.HiddenFor(model => model.BidID, new { id="bidItemID" })
<fieldset>
<legend>Edit Bid</legend>
<div class="display-label">#Html.LabelFor(model => model.CustomerName)</div>
<div class="display-field">
#Html.DisplayFor(model => model.CustomerName)
</div>
<div class="display-label">#Html.LabelFor(model => model.BidName)</div>
<div class="display-field">
#Html.DisplayFor(model => model.BidName)
</div>
<div class="editor-label">#Html.LabelFor(model => model.Amount)</div>
<div class="editor-field">
#Html.EditorFor(model => model.Amount)
</div>
<div class="editor-label">#Html.LabelFor(model => model.BidTime)</div>
<div class="editor-field">
#Html.EditorFor(model => model.BidTime)
</div>
</fieldset>
}
Where is it getting this metadata from and how can I stop it?

Answer 1

It's marked as such since the type in the view model is an int.
It's adding the html due to this line:
#Html.HiddenFor(model => model.BidID, new { id="bidItemID" })
Why is it a problem that the extra attributes are present?
If it really is problematic, try changing the type of BidId to int? (a nullable int).