我如何在ASP.NET MVC中修复此错误

Question

Inside my Index.cshtml , I have a DropDownList populated with data. On the selection of DropDownList item, I am loading partial views using ajax . These partial views are forms, when filled, the data is inserted into the database. After the insertion, I want to go the Index.cshtml that has populated the DropDownList initially, but it doesn't work and gives the error:

An exception of type 'System.InvalidOperationException' occurred in System.Web.Mvc.dll but was not handled in user code Additional information: There is no ViewData item of type 'IEnumerable' that has the key 'TemplatesCategory'.

Here is my controller ----

 public class templateController : Controller
    {
        PulseContext db = new PulseContext();
        public ActionResult Index()
        {
            ViewBag.TemplatesCategory = new SelectList(db.Templates, "Id", "templateName");
            return View();
        }
        [HttpGet]
        public PartialViewResult Clothing()
        {
            return PartialView("_ClothingTemplate");
        }
        [HttpPost]
        public ActionResult Clothing(templateClothing tc)
        {
            db.templateClothings.Add(tc);
            db.SaveChanges();
            return View("Index");
        }

Here is my view -----

    @model Pulse.Models.Templates

    @{
        ViewBag.Title = "Index";
    }
    <div class="container">
        <script src="~/Scripts/jquery-2.2.3.min.js"></script>
        <script src="~/Scripts/bootstrap.min.js"></script>
        <h2>Select your Template</h2>
        @Html.DropDownList("TemplatesCategory")
        <script type="text/javascript">
        $(document).ready(function () {
            $("#TemplatesCategory").change(function () {
                var choice = this.value;
                if (choice === "1") {
                    $.ajax({
                        url: '/template/Footwear',
                        contentType: 'application/html;charset=utf-8',
                        type: 'GET',
                        datatype:'html'
                    })
                    .success(function(result){
                    $('#templateContainer').html(result)
                })
                }
                else if (choice === "2") {
                    $.ajax({
                        url: '/template/Accessory',
                        contentType: 'application/html;charset=utf-8',
                        type: 'GET',
                        datatype: 'html'
                    })
                    .success(function (result) {
                        $('#templateContainer').html(result)
                    })
                }
                else if (choice === "3") {
                    $.ajax({
                        url: '/template/Clothing',
                        contentType: 'application/html;charset=utf-8',
                        type: 'GET',
                        datatype: 'html'
                    })
                    .success(function (result) {
                        $('#templateContainer').html(result)
                    })
                }
            });
        });
        </script>
        <div id="templateContainer"></div>
    </div>

Here is my model --

namespace Pulse.Models
{
    using System;
    using System.Collections.Generic;

    public partial class Templates
    {
        public Templates()
        {
            this.templateAccessoriesTbls = new HashSet<templateAccessories>();
            this.templateClothingTbls = new HashSet<templateClothing>();
            this.templateFootwearTbls = new HashSet<templateFootwear>();
        }

        public int Id { get; set; }
        public string templateName { get; set; }

        public virtual ICollection<templateAccessories> templateAccessoriesTbls { get; set; }
        public virtual ICollection<templateClothing> templateClothingTbls { get; set; }
        public virtual ICollection<templateFootwear> templateFootwearTbls { get; set; }
    }
}

Please help me how i can fix this error and also, how to redirect to index page with populated dropdown.

Answer 1

In your case this is what could be done to call the Index method before rendering the View you want

return RedirectToAction("Index"); 

instead of : return View("Index");

So your Clothing should be like below

    [HttpPost]
    public ActionResult Clothing(templateClothing tc)
    {
        db.templateClothings.Add(tc);
        db.SaveChanges();
        return RedirectToAction("Index");
    }

This will recall the Index method and render the View you want