ASP.Net MVC将项目添加到绑定下拉列表

Question

My page view currently has a dropdownlist on it that is getting bound to a collection from the controller. This is working fine, However I want to insert an item to the top of the dropdownlist that is not in my collection eg the list currently gets the following items

Open
Closed

I want to add a third option of "All" but I don't want to add this option to my database. In Webforms I would have just bound the control then inserted another item however it seems this is not possible with MVC, am I right in thinking I will need to add some Javascript to the view to add this new item once the dropdownlist has been bound?

Thanks

Answer 1

No. Construct your data as a list of SelectListItems and prepend in the controller.

   var list = db.Table
                .Select( t => new SelectListItem
                              { 
                                  Key = t.ID.ToString(),
                                  Value = t.Name
                              } )
                .ToList();
   list.Insert( 0, new SelectListItem { Key = "-1", Value = "All" } );

   ViewData["TableSelect"] = list;

On the view side:

   <%= Html.DropDownList( "TableID",
                          (IEnumerable<SelectListItem>)ViewData["TableSelect"] ) %>

Answer 2

Newer implementation

var list = _db.Status.ToList();
list.Add(new Status(){DevelopmentStatusID = -1, DevelopmentStatusDesc = "All"});
var result = list.OrderBy(d => d.StatusID).ToList();

ViewBag.StatusID = new SelectList(result, "StatusID", "StatusDesc");

Then in the index.html

    @Html.DropDownList("StatusID", null, htmlAttributes: new {@class = "form-control"})

Answer 3

Simple

you can make it as you wish in controller.

and pass it in viewdata.

other option is directly in view page.

<%= Html.DropDownList("DropDown","all" )%>

But you can add only one option..

Make sure you are not storing added options in ur db, right? so before you save it, check option value in action and apply your logic.