The viewdata item that has the key 'institutionid' is of type 'system.int32' but must be of type 'ienumerable<selectlistitem>

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Hello,

I have interrelated tables, Students has one to many relation with Enrollment, while Enroll further has relations with Institution, Session , Class and Section Tables, I created a ViewModel StudentVM

and wanted to insert data in Student table as well as Enrollment.

When I enter data in form and submit then it works ok.

but when I submit blank and leave some required fields I get this error. the Error is below

HTML

Server Error in '/' Application.
The ViewData item that has the key 'InstitutionID' is of type 'System.Int32' but must be of type 'IEnumerable<SelectListItem>'.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.InvalidOperationException: The ViewData item that has the key 'InstitutionID' is of type 'System.Int32' but must be of type 'IEnumerable<SelectListItem>'.

Source Error:


Line 19:             @Html.Label("Institution", htmlAttributes: new { @class = "control-label col-md-2" })
Line 20:             <div class="col-md-10">
Line 21:                 @Html.DropDownList("InstitutionID", ViewBag.InstitutionID as SelectList, "-Select Institution-",  new { @class = "form-control" } )
Line 22:             </div>
Line 23:         </div>

Source File: D:\Projects\ASP.net\MVC\School Management\SchoolMVC\SchoolMVC\Views\Students\Create.cshtml    Line: 21

Stack Trace:


[InvalidOperationException: The ViewData item that has the key 'InstitutionID' is of type 'System.Int32' but must be of type 'IEnumerable<SelectListItem>'.]
   System.Web.Mvc.Html.SelectExtensions.GetSelectData(HtmlHelper htmlHelper, String name) +355
   System.Web.Mvc.Html.SelectExtensions.SelectInternal(HtmlHelper htmlHelper, ModelMetadata metadata, String optionLabel, String name, IEnumerable`1 selectList, Boolean allowMultiple, IDictionary`2 htmlAttributes) +118
   System.Web.Mvc.Html.SelectExtensions.DropDownList(HtmlHelper htmlHelper, String name, IEnumerable`1 selectList, String optionLabel, Object htmlAttributes) +38
   ASP._Page_Views_Students_Create_cshtml.Execute() in D:\Projects\ASP.net\MVC\School Management\SchoolMVC\SchoolMVC\Views\Students\Create.cshtml:21
   System.Web.WebPages.WebPageBase.ExecutePageHierarchy() +197
   System.Web.Mvc.WebViewPage.ExecutePageHierarchy() +105
   System.Web.WebPages.StartPage.RunPage() +17
   System.Web.WebPages.StartPage.ExecutePageHierarchy() +64
   System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage) +78
   System.Web.Mvc.RazorView.RenderView(ViewContext viewContext, TextWriter writer, Object instance) +235
   System.Web.Mvc.BuildManagerCompiledView.Render(ViewContext viewContext, TextWriter writer) +107
   System.Web.Mvc.ViewResultBase.ExecuteResult(ControllerContext context) +291
   System.Web.Mvc.ControllerActionInvoker.InvokeActionResult(ControllerContext controllerContext, ActionResult actionResult) +13
   System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +56
   System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +420
   System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext controllerContext, IList`1 filters, ActionResult actionResult) +52
   System.Web.Mvc.Async.<>c__DisplayClass2b.<BeginInvokeAction>b__1c() +173
   System.Web.Mvc.Async.<>c__DisplayClass21.<BeginInvokeAction>b__1e(IAsyncResult asyncResult) +100
   System.Web.Mvc.Async.WrappedAsyncResult`1.CallEndDelegate(IAsyncResult asyncResult) +10
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
   System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) +27
   System.Web.Mvc.Controller.<BeginExecuteCore>b__1d(IAsyncResult asyncResult, ExecuteCoreState innerState) +13
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +29
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
   System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) +36
   System.Web.Mvc.Controller.<BeginExecute>b__15(IAsyncResult asyncResult, Controller controller) +12
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +22
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
   System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) +26
   System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.EndExecute(IAsyncResult asyncResult) +10
   System.Web.Mvc.MvcHandler.<BeginProcessRequest>b__5(IAsyncResult asyncResult, ProcessRequestState innerState) +21
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +29
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
   System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +28
   System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result) +9
   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +9836613
   System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step) +50
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +163

What I have tried:

view Model is:

HTML

namespace SchoolMVC.Models.ViewModel
{
    public class StudentsVM
    {
        public int StudentID { get; set; }
        [Required(ErrorMessage = "Admission number is required.")]
        public string AdmissionNo { get; set; }
        public string awrno { get; set; }
        public string boardregno { get; set; }
        [Required(ErrorMessage = "Student Name is required.")]
        public string StudentName { get; set; }
        [Required(ErrorMessage = "Father Name is required.")]
        public string FatherName { get; set; }
        public string MotherName { get; set; }
        public string FatherCNO { get; set; }
        public string FatherCNIC { get; set; }
        public string PermanentAddress { get; set; }
        public string TemporaryAddress { get; set; }
        public string ContactNo { get; set; }
        public string EmailID { get; set; }
        public Nullable<System.DateTime> DOB { get; set; }
        public string Gender { get; set; }
        public Nullable<System.DateTime> AdmissionDate { get; set; }
        public string Religion { get; set; }
        public byte[] Photo { get; set; }
        public string Nationality { get; set; }
        public string LastSchoolAttended { get; set; }
        public string Result { get; set; }
        public string PassPercentage { get; set; }
        public string House { get; set; }
        public string AccountNo { get; set; }
        public string AccountName { get; set; }
        public string Bank { get; set; }
        public string Branch { get; set; }
        public string IBANCode { get; set; }
        public int EnrollID { get; set; }
        public int InstitutionID { get; set; }
        public int SessionID { get; set; }
        public int ClassID { get; set; }
        public int SectionID { get; set; }
    }
}

And my Create Get and Post Methods are as below:

HTML

   public ActionResult Create()
        {
            ViewBag.ClassID = new SelectList(db.tblClasses, "ClassID", "ClassName");
            ViewBag.InstitutionID = new SelectList(db.tblInstitutes, "InstitutionID", "Institution");
            ViewBag.SessionID = new SelectList(db.tblSessions, "SessionID", "SessionName");
            return View();
        }

        // POST: Students/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 ActionResult Create( StudentsVM Student)
        {
            if (ModelState.IsValid)
            {
                tblStudent st = new tblStudent();
                st.StudentName = Student.StudentName;
                st.FatherName = Student.FatherName;
                st.AdmissionNo = Student.AdmissionNo;
                db.tblStudents.Add(st);
                db.SaveChanges();
                // InsertEnrollmet(Student);
                var stuID = st.StudentID;
                tblEnrollment en = new tblEnrollment();
                en.StudentID = stuID;
                en.InstitutionID = Student.InstitutionID;
                en.SessionID = Student.SessionID;
                en.ClassID = Student.ClassID;
                en.SectionID = Student.SectionID;
                db.tblEnrollments.Add(en);
                db.SaveChanges();
                return RedirectToAction("Index");
            }
ViewBag.ClassID = new SelectList(db.tblClasses, "ClassID", "ClassName");
            ViewBag.InstitutionID = new SelectList(db.tblInstitutes, "InstitutionID", "Institution");
            ViewBag.SessionID = new SelectList(db.tblSessions, "SessionID", "SessionName");

            return View(Student);
        }

In View it is like below

HTML

<div class="form-group">
          @Html.Label("Institution", htmlAttributes: new { @class = "control-label col-md-2" })
          <div class="col-md-10">
              @Html.DropDownList("InstitutionID", (IEnumerable<SelectListItem>) ViewData["InstitutionID"] as SelectList , "-Select Institution-",  new { @class = "form-control" } )
              @Html.ValidationMessageFor(model => model.InstitutionID, "", new { @class = "text-danger" })
          </div>
      </div>

Posted 21-Jul-20 21:05pm

nyt1972

Updated 23-Jul-20 21:23pm

v3

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Comments

[no name] 22-Jul-20 13:33pm

Does "SelectList" sound like it should return a scalar or a collection?

nyt1972 22-Jul-20 13:36pm

It should return a collection, and it does, but the error comes if I don't select any or if I leave any required field blank.

I expect the error message that InstitutionID not selected or something like this but it throws this IENUMERABLE error.

[no name] 22-Jul-20 16:32pm

If that's the case, you're assigning collections to scalar properties.

nyt1972 23-Jul-20 3:04am

Passing Select List to Post create method resolved the issue

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Sandeep Mewara · Answer 1 · 2020-07-23T21:23:00

Quote:
The ViewData item that has the key 'InstitutionID' is of type 'System.Int32' but must be of type 'IEnumerable<selectlistitem>'.

Quote:
@Html.DropDownList("InstitutionID", (IEnumerable<selectlistitem>) ViewData["InstitutionID"] as SelectList , "-Select Institution-", new { @class = "form-control" } )

Quote:
ViewBag.InstitutionID = new SelectList(db.tblInstitutes, "InstitutionID", "Institution");

Try below:

@Html.DropDownList("InstitutionID", (IEnumerable<SelectListItem>)ViewBag.InstitutionID, "-Select Institution-", new { @class ="form-control" })

Reference: http://msdn.microsoft.com/en-us/library/system.web.mvc.html.selectextensions.dropdownlistfor%28v=vs.108%29.aspx[^]

The viewdata item that has the key 'institutionid' is of type 'system.int32' but must be of type 'ienumerable<selectlistitem>

1 solution

Solution 1

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