Set DropdownList SelectedItem after submit

I have a dropdownlist is set to '--Select Item--' when the form is loaded first time. I don't see the Selected Item getting selected after I submit the for开发者_C百科m. It is set to '--Selected Item--' again. What could be the problem?

<%= Html.DropDownList("lstDetails", new SelectList((IEnumerable)ViewData["DetailList"], "ID", "Details"), "--Select Item--")%>

Thanks..

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I assume you wish to save the selected item somewhere.

<%: Html.DropDownFor(selectedId, new SelectList((IEnumerable)ViewData["DetailList"], "ID", "Details", (IEnumerable)ViewData["DetailList"].FirstOrDefulft(x => x.Id == selectedId), "--SelectItem--") %>

You need to store the information which item was selected. I used here an int called

int selectedId

I assumed you have a Id field in your detailList items.

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The easiest way is to put SelectList in the model. (Just make sure you are creating the SelectList in the constructor of the model).

View:

<%= Html.DropDownList("lstDetails", Model.DetailList)%>

Controller:

[AcceptVerbs(HttpVerbs.Post)]
public ActionResult MyController(MyModel model)
{
     return View(model);
}

Model:

class MyModel
{
   public SelectList DetailList;

   public MyModel()
   {
      DetailList = new SelectList(....
   }
}

So after you post back, if you return the view with the same model then the form will look the same as before you submitted the form.