ASP.NET MVC。 如何在部分中插入SelectList？

Question

I would like to create an partial which holds a select for a previously configured list.

in the controller I'm able to create the SelectList and add it to ViewBag . However ViewBag defined on controller are not propagated to the Partial. Partials have its own ViewBag

for instance this POCO item class:

class MyItem{
    [Key] 
    public int id {get;set;}
    public int Forign_element_id {get;set;}
    public string PropB {get;set;}
}   

And its Partial like this:

@model MyItem

@Html.HiddenFor(model => model.id)

@Html.LabelFor(model => model.PropA)
@Html.DropDownListFor(model => model.Forign_element_id, (SelectList)ViewBag.MySelectList) 
//Error! ViewBag are not propageted to the EditorTemplate

@Html.LabelFor(model => model.PropB)
@Html.EditorFor(model => model.PropB)

Important. Each item in the list has a Forign_element_id value. This values must be selected in select box at rendering.

Answer 1

Pass the SelectList as an object using one of the overloads that accepts additionalViewData .

In the main view (assumes your model has a property named MyProperty which is typeof MyItem )

@Html.EditorFor(m => m.MyProperty, new { options = (SelectList)ViewBag.MySelectList })

and in your MyItem.cshtml template

@Html.DropDownListFor(m => m.Forign_element_id, (SelectList)ViewData["options"])

Answer 2

Try this in your editor template: Instead of (Dictionary) cast it to your type; in my case, I was passing Dictionary from the calling layer; so I have used it as new SelectList(list, "Key", "Value"), change accordingly

Name of Editor Template - DropdownList

@{
var defaultText = (string)ViewData["DefaultText"];
//var list = (Dictionary<string, string>) ViewData["List"]; -- my List was Dictionary
var list = (List<YourType>) ViewData["List"];
}
@Html.DropDownListFor(model => model,
new SelectList(list, "Key", "Value"),
defaultText,
new { @class = "form-  control", style="height: auto;width:90%"   })

EDIT - adding calling code

@Html.EditorFor(model => model.YourModel, "DropdownList", new { List = ViewBag.YourList, DefaultText = "Select one item"})

where "DropdownList" is editor template name

Answer 3

controller:

private IEnumerable<SelectListItem> GetMyItemsSelectItems()
{
   return (from s in _rep.GetMyItems()
           select new SelectListItem
            {
                Text = s.MyItemName,
                Value = s.ID.ToString()
             }).AsEnumerable();
 }

 public ActionResult Create()
 {
     ViewBag.MyItems = GetMyItemsSelectItems();

     return View(new MyItem { ID = 1, Forign_element_id = 2});
 }

View:

@model App.Models.MyItem

@Html.DropDownListFor(m => m.ID, new SelectList(ViewBag.MyItems, 
                                                   "Value", "Text"))
@Html.DropDownListFor(m => m.Forign_element_id, 
                        new SelectList(ViewBag.MyItems, "Value", "Text"))