c# - The model item passed into the dictionary is of type 'System.Linq.GroupedEnumerable`3 but this requires 'System.Collections.Generic.IEnumerable`1 -
i following error when trying run application:
the model item passed dictionary of type 'system.linq.groupedenumerable'3[webapplication1.question,system.int32,webapplication1.question]', dictionary requires model item of type 'system.collections.generic.ienumerable`1[webapplication1.question]'.
here stack trace:
[invalidoperationexception: model item passed dictionary of type 'system.linq.groupedenumerable`3[webapplication1.question,system.int32,webapplication1.question]', dictionary requires model item of type 'system.collections.generic.ienumerable`1[webapplication1.question]'.] system.web.mvc.viewdatadictionary`1.setmodel(object value) +175 system.web.mvc.viewdatadictionary..ctor(viewdatadictionary dictionary) +107 system.web.mvc.webviewpage`1.setviewdata(viewdatadictionary viewdata) +49 system.web.mvc.razorview.renderview(viewcontext viewcontext, textwriter writer, object instance) +99 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() +9765901 system.web.httpapplication.executestep(iexecutionstep step, boolean& completedsynchronously) +155 and questionscontroller :
// get: questions public actionresult index() { var questions = db.questions.include(q => q.step); return view(questions.tolist().groupby(x=>x.idstep)); } // get: questions/details/5 public actionresult details(int? id) { if (id == null) { return new httpstatuscoderesult(httpstatuscode.badrequest); } question question = db.questions.find(id); if (question == null) { return httpnotfound(); } return view(question); } // get: questions/create public actionresult create() { viewbag.idstep = new selectlist(db.steps, "idstep", "namestep"); return view(); } // post: questions/create // protect overposting attacks, please enable specific properties want bind to, // more details see http://go.microsoft.com/fwlink/?linkid=317598. [httppost] [validateantiforgerytoken] public actionresult create([bind(include = "idquestion,idstep,question1")] question question) { if (modelstate.isvalid) { db.questions.add(question); db.savechanges(); return redirecttoaction("index"); } viewbag.idstep = new selectlist(db.steps, "idstep", "namestep", question.idstep); return view(question); } // get: questions/edit/5 public actionresult edit(int? id) { if (id == null) { return new httpstatuscoderesult(httpstatuscode.badrequest); } question question = db.questions.find(id); if (question == null) { return httpnotfound(); } viewbag.idstep = new selectlist(db.steps, "idstep", "namestep", question.idstep); return view(question); } // post: questions/edit/5 // protect overposting attacks, please enable specific properties want bind to, // more details see http://go.microsoft.com/fwlink/?linkid=317598. [httppost] [validateantiforgerytoken] public actionresult edit([bind(include = "idquestion,idstep,question1")] question question) { if (modelstate.isvalid) { db.entry(question).state = entitystate.modified; db.savechanges(); return redirecttoaction("index"); } viewbag.idstep = new selectlist(db.steps, "idstep", "namestep", question.idstep); return view(question); } // get: questions/delete/5 public actionresult delete(int? id) { if (id == null) { return new httpstatuscoderesult(httpstatuscode.badrequest); } question question = db.questions.find(id); if (question == null) { return httpnotfound(); } return view(question); } // post: questions/delete/5 [httppost, actionname("delete")] [validateantiforgerytoken] public actionresult deleteconfirmed(int id) { question question = db.questions.find(id); db.questions.remove(question); db.savechanges(); return redirecttoaction("index"); } protected override void dispose(bool disposing) { if (disposing) { db.dispose(); } base.dispose(disposing); } } } and view :
@model ienumerable<webapplication1.question> @{ viewbag.title = "index"; } <h2>index</h2> <p> @html.actionlink("create new", "create") </p> <table class="table"> <tr> <th> </th> <th> @html.displaynamefor(model => model.step.namestep) </th> <th> @html.displaynamefor(model => model.question1) </th> <th></th> </tr> @foreach (var item in model) { <tr> <td> @html.actionlink("edit", "edit", new { id = item.idquestion }) | @html.actionlink("details", "details", new { id = item.idquestion }) | @html.actionlink("delete", "delete", new { id = item.idquestion }) </td> <td> @html.displayfor(modelitem => item.step.namestep) </td> <td> @html.displayfor(modelitem => item.question1) </td> </tr> } </table>
the problem originated how returning view page code:
return view(questions.tolist().groupby(x => x.idstep)); the groupby linq method produces groupedenumerable result (not ienumerable) , since model expects ienumerable collection given @model directive, there's no direct conversion groupedenumerable ienumerable unless using method returns ienumerable, i.e. tolist.
try using groupby before tolist given below, action method returns list<question> implements ienumerable:
public actionresult index() { var questions = db.questions.include(q => q.step).groupby(x => x.idstep).tolist(); return view(questions); } nb: if you're not sure putting groupby directly after include, use asenumerable convert join query collection before start grouping.
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