title: First item in DropDownListFor control should not be selected initially
body: <p>My OpenTestplanListViewModel has a DisplayList with 3 items bound to the DropDownList.</p>
  
  <p>When the user selects explicitly no item in the DropDownList always the first is automatically selected.</p>
  
  <p>Using a ListBoxFor instead a DropDownListFor I have not this problem.
  Is it somehow possible to tell the DropDownListFor "Do not select any item initially!" ?</p>
  
  <pre><code>@model ITMS.Web.Models.OpenTestplanListViewModel
  
  @{
      Layout = null;   
  } 
  
  @using (Html.BeginForm("Open", "Testplan"))
  { 
      @Html.ValidationSummary(false)      
      @Html.DropDownListFor(x =&gt; x.TestplanIdAndTemplateId, new SelectList(Model.DisplayList, "TestplanIdAndTemplateId", "Name"), new { @class = "listviewmodel" })  
  }
  
  public class OpenTestplanListViewModel
  {
      [Required(ErrorMessage = "No item selected.")]
      public string TestplanIdAndTemplateId { get; set; } 
      public IEnumerable&lt;OpenTestplanViewModel&gt; DisplayList { get; set; }
  
      public int? SelectedTestplanId
      {
          get
          {
              return !String.IsNullOrEmpty(TestplanIdAndTemplateId) ? Convert.ToInt32(TestplanIdAndTemplateId.Split(new[] { '_' }).First()) : (int?)null;
          }
      }
      public int? SelectedTemplateId
      {
          get
          {
              return !String.IsNullOrEmpty(TestplanIdAndTemplateId) ? Convert.ToInt32(TestplanIdAndTemplateId.Split(new[] { '_' }).Last()) : (int?)null;
          }
      }
  }
  </code></pre>