Dropdown List Not Saving The Selected Value To Database

In the following code i want to save the value selected by user from drop downlist into database. but whatever value is selected by user, first value of dropdown lsit is saved to database

View
<% =Html.DropDownList("lstUsertype", (SelectList)ViewData["UserTypeID"])%>
Controller
public ActionResult CreateUser()
{
UmUser _UmUser = new UmUser();
UMRepository _UMRepository = new UMRepository();
EvoLetDataContext db = new EvoLetDataContext();
ViewData["UserTypeID"] = new SelectList(_UMRepository.FillUserTypes(), "UserTypeID", "UserType",2);
return View(_UmUser);
}
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult CreateUser(UmUser _umUser)
{
//try
//{
if (ModelState.IsValid)
{
//try
//{
UserRepository _UserRepository = new UserRepository();
_UserRepository.Add(_umUser);
_UserRepository.Save();
return RedirectToAction("Details", new { id = _umUser.UserID });
/*}
catch
{
ModelState.AddModelErrors(_umUser.GetRuleViolations());
}*/
}
return View();
//}
/*catch
{
return View();
}*/
}