The model item passed into the dictionary is of type 'System.Collections.Generic.List error

Question

I get the following error when trying to run my application:

'The model item passed into the dictionary is of type 'System.Collections.Generic.List1[MvcApplication2.Models.Blog]', but this dictionary requires a model item of type 'System.Collections.Generic.IEnumerable1[MvcApplication2.Models.BlogDataEntities]'. '

Here is the stack trace:

          [InvalidOperationException: The model item passed into the dictionary is of type          'System.Collections.Generic.List`1[MvcApplication2.Models.Blog]', but this dictionary requires a model item of type 'System.Collections.Generic.IEnumerable`1[MvcApplication2.Models.BlogDataEntities]'.]
           System.Web.Mvc.ViewDataDictionary`1.SetModel(Object value) +324899
   System.Web.Mvc.ViewDataDictionary..ctor(ViewDataDictionary dictionary) +377
System.Web.Mvc.WebViewPage`1.SetViewData(ViewDataDictionary viewData) +48
System.Web.Mvc.RazorView.RenderView(ViewContext viewContext, TextWriter writer, Object instance) +99
 System.Web.Mvc.BuildManagerCompiledView.Render(ViewContext viewContext, TextWriter writer) +115
 System.Web.Mvc.ViewResultBase.ExecuteResult(ControllerContext context) +303
  System.Web.Mvc.ControllerActionInvoker.InvokeActionResult(ControllerContext controllerContext, ActionResult actionResult) +13
 System.Web.Mvc.<>c__DisplayClass1c.<InvokeActionResultWithFilters>b__19() +23
 System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilter(IResultFilter filter,   ResultExecutingContext preContext, Func`1 continuation) +260
 System.Web.Mvc.<>c__DisplayClass1e.<InvokeActionResultWithFilters>b__1b() +19
               System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext controllerContext, IList`1 filters, ActionResult actionResult) +177
System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext controllerContext, String actionName) +343
 System.Web.Mvc.Controller.ExecuteCore() +116
System.Web.Mvc.ControllerBase.Execute(RequestContext requestContext) +97
System.Web.Mvc.ControllerBase.System.Web.Mvc.IController.Execute(RequestContext requestContext) +10
System.Web.Mvc.<>c__DisplayClassb.<BeginProcessRequest>b__5() +37
System.Web.Mvc.Async.<>c__DisplayClass1.<MakeVoidDelegate>b__0() +21
System.Web.Mvc.Async.<>c__DisplayClass8`1.<BeginSynchronous>b__7(IAsyncResult _) +12
System.Web.Mvc.Async.WrappedAsyncResult`1.End() +62
System.Web.Mvc.<>c__DisplayClasse.<EndProcessRequest>b__d() +50
System.Web.Mvc.SecurityUtil.<GetCallInAppTrustThunk>b__0(Action f) +7
System.Web.Mvc.SecurityUtil.ProcessInApplicationTrust(Action action) +22
System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +60
System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result) +9
      System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +8969117
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +184

And here is my BlogController:

         using System;
         using System.Collections.Generic;
           using System.Linq;
           using System.Web;
           using System.Web.Mvc;
           using MvcApplication2.Models;

               namespace MvcApplication2.Controllers
              {
       public class BlogController : Controller
       {
    //
    // GET: /Blog/

    public ActionResult Index()
    {
        using (var db = new BlogDataEntities())
        {
            return View(db.Blogs.ToList());
        }

    }

    //
    // GET: /Blog/Details/5

    public ActionResult Details(int id)
    {
        return View();
    }

    //
    // GET: /Blog/Create

    public ActionResult Create()
    {
        return View();
    }

    //
    // POST: /Blog/Create

    [HttpPost]
    public ActionResult Create(Blog blog)
    {
        try
        {
            using (var db = new BlogDataEntities())
            {
                db.Blogs.Add(blog);
                db.SaveChanges();
            }

            return RedirectToAction("Index");
        }
        catch
        {
            return View();
        }
    }


    //
    // GET: /Blog/Edit/5

    public ActionResult Edit(int id)
    {
        using (var db = new BlogDataEntities())
        {
            return View(db.Blogs.Find(id));
        }

    }

    //
    // POST: /Blog/Edit/5

    [HttpPost]
    public ActionResult Edit(int id, Blog blog)
    {
        try
        {
            using (var db = new BlogDataEntities())
            {
                db.Entry(blog).State = System.Data.EntityState.Modified;
                db.SaveChanges();
                return RedirectToAction("Index");
            }
        }
        catch
        {
            return View();
        }
    }



    //
    // GET: /Blog/Delete/5

    public ActionResult Delete(int id)
    {
        using (var db = new BlogDataEntities())
        {
            return View(db.Blogs.Find(id));
        }
    }

    [HttpPost]
    public ActionResult Delete(int id, Blog blog)
    {
        try
        {
            using (var db = new BlogDataEntities())
            {
                db.Entry(blog).State = System.Data.EntityState.Deleted;
                db.SaveChanges();
            }
            return RedirectToAction("Index");
        }
        catch
        {
            return View();
        }
    }
}

}

Solution

The problem is that you have a controller action which passes a List<Blog> instance to a view which is strongly typed to IEnumerable<BlogDataEntities> which is not possible.

So you have a controller action like this:

public ActionResult Foo()
{
    List<Blog> blogs = ...
    return View(blogs);
}

and the corresponding view:

@model IEnumerable<BlogDataEntities>
...

Another possibility for this error occurring is that your view is typed to the correct model that the controller action passed but inside this view you tried to render a partial which is typed to a different model:

@model List<Blog>
...
@Html.Partial("_MyPartial")

where _MyPartial.cshtml looks like this:

@model IEnumerable<BlogDataEntities>
...

which once again is not possible. In this case you could use the second argument to the Html.Partial helper to provide a correct model for this partial.