asp.net mvc - No parameterless constructor defined for this object. (Debug never reaches any controller action?) -

i hate these kind of errors.

i have asp.net core mvc form. when submit form dreaded "no parameterless constructor defined object." error.

i can't seem hit in debugger me find have went wrong.

my controller:

using brand.extensions; using brand.models; using microsoft.aspnetcore.http; using microsoft.aspnetcore.mvc;  namespace brand.controllers {     public class contentcontroller : controller     {          public iactionresult index()         {             return view();         }          [httpget]         public iactionresult upload()         {             return view();         }          [httppost]         [validateantiforgerytoken]         public iactionresult upload(uploadedcontentmodel uploadedcontentmodel, formcollection formcollection, iformfilecollection uploadedfiles)         {             contentextensions contentextensions = new contentextensions();             fileextensions fileextensions = new fileextensions();             filemodel file = new filemodel();             file = fileextensions.getfilemodel(uploadedfiles["file"]);             uploadedcontentmodel.file = fileextensions.uploadfile(file).id;              filemodel thumbnail = new filemodel();             thumbnail = fileextensions.getfilemodel(uploadedfiles["thumbnail"]);             uploadedcontentmodel.thumbnail = fileextensions.uploadfile(thumbnail).id;              uploadedcontentmodel.id = contentextensions.uploadcontent(uploadedcontentmodel).id;              return view();         }     } } 

my model:

public class uploadedcontentmodel {     public guid id { get; set; }     public string title { get; set; }     public string description { get; set; }     public guid file { get; set; }     public guid thumbnail { get; set; }     public string contenttype { get; set; }      public string solutions { get; set; }     public string industries { get; set; }     public string additionaltags { get; set; }     public datetime publish { get; set; }     public datetime expire { get; set; }     public string authorizedroles { get; set; }     public string author { get; set; }     public datetime created { get; set; } }