使用实体框架在mvc中返回部分视图时从数据库填充下拉列表

Question

heloo m using entity framework in mvc5 i want to populate dropdown list from database in users View by picking the data from suppliers model and m also returning a partialView instead of simple View. let me share my codes here.

this is Supplier Model Class.

[MetadataType(typeof(MetadataForSupplier))]
public partial class Supplier
{
}

public class MetadataForSupplier
{
    public int SupplierId { get; set; }
    public string Name { get; set; }
    public string ContactPerson { get; set; }
    public string Address { get; set; }
}

this is usersControler Create Method i want to populate dropdown in create View

    // GET: /Frames/Create
    public ActionResult Create()
    {
        return PartialView("_Create");
    }

    // POST: /Frames/Create
    // To protect from overposting attacks, please enable the specific properties you want to bind to, for 
    // more details see http://go.microsoft.com/fwlink/?LinkId=317598.
    [HttpPost]
    [ValidateAntiForgeryToken]
    public async Task<ActionResult> Create([Bind(Include="FrameId,Name,FrameCode,FrameFor,Brand,Material,Color,FrameType,FrameShape,Bridge,LensWidth,FrameWidth,TempleLength,LensHeight,FrameWeight,Quantity,PurchaseRate,SaleRate,Supplier,Discription,Status,CreatedOn")] Frame frame)
    {

        if (ModelState.IsValid)
        {
            db.Frames.Add(frame);
            await db.SaveChangesAsync();
            return Json(new { success = true });
        }

        //IEnumerable<SelectListItem> SuppliersList = db.Suppliers.Select(c => new SelectListItem
        //{
        //    Value = c.Name,
        //    Text = c.Name

        //});

        ViewData["SupplierList"] = new SelectList(db.Suppliers, "Name", "Name");

        return PartialView("_Create", frame);
    }

and here is _Create.cshtml partialView Code

<div class="col-md-3">
                    @Html.LabelFor(model => model.Supplier)
                    @Html.DropDownList("Suppliers", (SelectList)ViewData["SupplierList"))
                    @Html.EditorFor(model => model.Supplier, new { htmlAttributes = new { @class = "form-control ", style = "width: 200px", @placeholder = "Supplier" } })
                    @Html.ValidationMessageFor(model => model.Supplier)
                </div>

Answer 1

You can use a different overload of Html.DropDownList more conveniently:

Change:

ViewData["SupplierList"] = new SelectList(db.Suppliers, "Name", "Name");

to:

ViewBag.SuppliersList = new SelectList(db.Suppliers, "Name", "Name");

in your action. Then in your view:

@Html.DropDownList("SuppliersList")

By default, setting this initial string parameter will cause the helper method to search the ViewBag for a SelectList with the "SuppliersList" identifier.

Edit: Since you've requested css changes using the Html helper, we can do it this way.

ViewBag.SuppliersList = new SelectList(db.Suppliers, "SupplierId", "Name");

Then in the view:

@Html.DropDownList("SupplierId", ViewBag.SuppliersList as SelectList, new { @class = "someCssClass" })