[Solved] Combo/Autocomplete Retains Values Even When Model and ViewData are Cleared

[Sydney]

I have two telerik controls on a form (one is ComboBox, one is Autocomplete).  The form is for Adding a new student object.  There are two buttons:  Save, Save and New.   Save and New posts to the Controller's save method, but instead of redirecting back to a list of existing students, it is meant to return the Add Student screen.  I have the following code in the Controller action:

[AcceptVerbs(HttpVerbs.Post)]
public ActionResult AddStudent(StudentProfileDto student, int addAnother)
{
    var teacher = SessionWrapper.GetTeacher(HttpContext);
    var model = new EditStudentModel
    {
        Teacher = teacher
    };

    if (ModelState.IsValid)
    {
        AddStudentToTeacher(student);

        if (addAnother == 0)
            return RedirectToAction("StudentRoster");

        ViewData = null;
        model.Student = new StudentProfileDto();
    }
    else
    {
        model.Student = student;
    }

    return View(model);
}

All non-Telerik controls are cleared as expected.  However, the Telerik controls retain the values from the Student that was just added.

Here's one of the Telerik control's code:

@{
  Html.Telerik()
      .AutoCompleteFor(model => model.Student.TagString)
      .Encode(false)
      .BindTo(Model.Teacher.Tags)
    //.AutoFill(true)
      .HtmlAttributes(new { @class = "form-input" })
      .HighlightFirstMatch(true)
      .Filterable(filtering =>
      {
        filtering.FilterMode(AutoCompleteFilterMode.StartsWith);
      })
      .Multiple(multi =>
      {
        multi.Separator(",")
            .Enabled(true);

      })
      .Render();
}

[Georgi Krustev]

Hello Sydney,

 
In order to persist custom value sent to the server using ComboBox, we use ValueProvider of the controller. As you probably noticed the combobox UI component has two inputs, one for SelectListItem.Text and second for the SelectListItem.Value. ASP.NET MVC will persist in the ModelState only the SelectListItem.Value which corresponds to the ComboBox.Name. The SelectListItem.Text is persisted only in the FormCollection.
Hence if you need to clear ComboBox UI component I will suggest you call RedirectToAction or to clear combobox on the client-side. 

Regards,
Georgi Krustev
the Telerik team