Apply class to parent when validation error

Question

I'm using Bootstrap with ASP.NET MVC and using @Html.TextboxFor<...>(...) helper to create textboxes for my model.

My current code looks as below.

<div class="form-group">
  @Html.LabelFor(m=>m.Email,"Email Address")

  <div class="input-group">
    @Html.TextBoxFor(m=> m.Email, 
            new { @class = "form-control", placeholder = "Enter e-mail" })
            <span class="input-group-addon">@@mydomain.com</span>
   </div>
   <span>@Html.ValidationMessageFor(m=>m.Email) </span>
 </div>

This works fine, though I want to add 'has-error' css class to the top div (the one with class=form-group). This is because I want to use the bootstrap classes when there's an error.

I understand that the HTML helper and validation adds 'input-validation-error' class, but I want the bootstrap class instead, and instead of the input, I want it on the parent div, so the styling works as expected.

How can I accomplish this ?