ASP NET MVC No parameterless constructor defined for this object

Question

Server Error in     Application  --------------------------------------------------------------------------------  No parameterless constructor defined for this object   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 MissingMethodException  No parameterless constructor defined for this object   Source Error     Line 16              HttpContext Current RewritePath Request ApplicationPath  false   Line 17              IHttpHandler httpHandler   new MvcHttpHandler    Line 18              httpHandler ProcessRequest HttpContext Current   Line 19              HttpContext Current RewritePath originalPath  false   Line 20              I was following Steven Sanderson s  Pro ASP NET MVC Framework  book  On page 132  in accordance with the author s recommendation  I downloaded the ASP NET MVC Futures assembly  and added it to my MVC project   Note  This could be a red herring    After this  I could no longer load my project  The above error stopped me cold   My question is not   Could you help me fix my code    Instead  I d like to know more generally    How should I troubleshoot this issue  What should I be looking for    What might the root cause be    It seems like I should understand routing and controllers at a deeper level than I do now

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In my case  my class had the  Serializable  attribute    You are required to have a constructor that takes no parameters if your class is  Serializable

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I got the same error  the culprit in my case was the constructor which was neither public nor private      No parameterless constructor defined for this object       Exception Details  System MissingMethodException  No parameterless constructor defined for this object    Repro code  Make sure the constructor has public before it   public class Chuchi          Chuchi         The problem is this line  Public is missing                    initialization          name  Tom Hanks               public string name               get          set

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All of the answers say to create a parameters less constructor which isn t ideal if you don t want any other devs using it and only the model binder   The attribute  Obsolete  For model binding only   true   above a public constructor will throw a compiler error if another dev tries to use this  Took me ages to find this  hope it helps someone

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You can get this exception at many different places in the MVC framework  e g  it can t create the controller  or it can t create a model to give that controller    The only easy way I ve found to diagnose this problem is to override MVC as close to the exception as possible with your own code   Then your code will break inside Visual Studio when this exception occurs  and you can read the Type causing the problem from the stack trace   This seems like a horrible way to approach this problem  but it s very fast  and very consistent   For example  if this error is occurring inside the MVC DefaultModelBinder  which you will know by checking the stack trace   then replace the DefaultModelBinder with this code   public class MyDefaultModelBinder   System Web Mvc DefaultModelBinder       protected override object CreateModel System Web Mvc ControllerContext controllerContext  System Web Mvc ModelBindingContext bindingContext  Type modelType                return base CreateModel controllerContext  bindingContext  modelType             And update your Global asax cs   public class MvcApplication   System Web HttpApplication           protected void Application Start object sender  EventArgs e                ModelBinders Binders DefaultBinder   new MyDefaultModelBinder              Now the next time you get that exception  Visual Studio will stop inside your MyDefaultModelBinder class  and you can check the  modelType  property to see what type caused the problem   The example above works for when you get the  No parameterless constructor defined for this object  exception during model binding  only   But similar code can be written for other extension points in MVC  e g  controller construction

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I had a similar problem  and basically the point is that there are some arguments in the action method that were not supplied by the Model Binding process   and in other words these fields were not submitted by the submitting page    This problem will come up even if all arguments but one are supplied  and even if the one missing is a nullable type   The problem might also be a result of a typo  in which the name of the argument and name of the form field will not be identical   The solution is to 1  verify that the names match up 2  provide a default value for the argument 3  or provide another action method without this argument

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This can also be caused if your Model is using a SelectList  as this has no parameterless constructor   public class MyViewModel       public SelectList Contacts   get set        You ll need to refactor your model to do it a different way if this is the cause  So using an IEnumerable lt Contact gt  and writing an extension method that creates the drop down list with the different property definitions   public class MyViewModel       public Contact SelectedContact   get set        public IEnumerable lt Contact gt  Contacts   get set       public static MvcHtmlString DropDownListForContacts this HtmlHelper helper  IEnumerable lt Contact gt  contacts  string name  Contact selectedContact           Create a List lt SelectListItem gt   populate it  return DropDownList         Or you can use the  Mark and  krilovich approach  just need replace SelectList to IEnumerable  it s works with MultiSelectList too    public class MyViewModel               public Contact SelectedContact   get set            public IEnumerable lt SelectListItem gt  Contacts   get set

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I had this problem as well and thought I d share since I can t find my problem above   This was my code  return RedirectToAction  Overview   model Id    Calling this ActionResult   public ActionResult Overview int id   I assumed it would be smart enough to figure out that the value I pass it is the id paramter for Overview  but it s not  This fixed it   return RedirectToAction  Overview   new  id   model Id

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This error started for me when I added a new way to instantiate a class     Example       public class myClass                public string id  get  set             public List lt string gt  myList get  set                error happened after I added this          public myClass string id  List lt string gt  lst                          this id  id               this myList  lst                      The error was resolved when I added when I made this change  adding a parameterless constructor   I believe the compiler creates a parameterless constuctor by default but if you add your own then you must explicitly create it       public class myClass                public string id  get  set             public List lt string gt  myList get  set                error doesn t happen when I add this          public myClass                    error happened after I added this  but no longer happens after adding above          public myClass string id  List lt string gt  lst                          this id  id               this myList  lst

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So I have gotten that message before as well  when doing an ajax call   So what it s basically asking for is a constructor in that model class that is being called by the contoller  doesn t have any parameter   Here is an example   public class MyClass        public MyClass        so here would be your parameterless constructor

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I  got this error  I was using interfaces in my constructor and my dependency resolver wasn t able to resolve  when i registered it then the error went away

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You need the action that corresponds to the controller to not have a parameter   Looks like for the controller   action combination you have   public ActionResult Action int parameter         but you need   public ActionResult Action          Also  check out Phil Haack s Route Debugger to troubleshoot routes

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I got the same error when   Using a custom ModelView  both Actions  GET and POST  were passing the ModelView that contained two objects   public ActionResult Add int  categoryID                ProductViewModel productViewModel   new ProductViewModel              product              rootCategories                    return View productViewModel        And the POST also accepting the same model view    HttpPost   ValidateInput false   public ActionResult Add ProductModelView productModelView          Problem was the View received the ModelView  needed both product and list of categories info   but after submitted was returning only the Product object  but as the POST Add expected a ProductModelView it passed a NULL but then the ProductModelView only constructor needed two parameters Product  RootCategories   then it tried to find another constructor with no parameters for this NULL case then fails with  no parameterles      So  fixing the POST Add as follows correct the problem    HttpPost   ValidateInput false   public ActionResult Add Product product          Hope this can help somebody  I spent almost half day to find this out

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This happened to me  and the results on this page were a good resource that led me in many directions  but I would like to add another possibility   As stated in other replies  creating a constructor with parameters removes the implicit parameterless constructor  so you have to explicitly type it   What was my problem was that a constructor with default parameters also triggered this exception   Gives errors   public CustomerWrapper CustomerDto customer   null         Works   public CustomerWrapper CustomerDto customer       public CustomerWrapper   this null

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The same for me  My problem appeared because i forgot that my base model class already has property with the name which was defined in the view   public class CTX   DbContext       context with domain models     public DbSet lt Products gt  Products   get  set         Products  is the source property     public CTX     base  Entities         public class BaseModel   CTX         public class ProductModel   BaseModel         public class OrderIndexModel   OrderModel                and controller processing model      HttpPost   ValidateInput false   public ActionResult Index OrderIndexModel order            Nothing special  right  But then i define the view       lt div class  dataItem  gt       lt   Html Label  Products    gt       lt   Html Hidden  Products   Model index   gt       I FORGOT THAT I ALREADY HAVE PROPERTY CALLED  Products       lt   Html DropDownList  ProductList   Model products   gt       lt   Html ActionLink  Delete    D    gt   lt  div gt        which causes  Parameterless constructor  error on POST request   Hope that helps

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I d added a DropDownList to my form  however in my case it wasn t  and wasn t intended to be  submitted with the form as it was outside of the  lt form gt  lt  form gt  tags    Html DropDownList  myField   Model MyField    As the Model contained the field for display only  this also caused the No parameterless constructor defined for this object error because the field wasn t submitted at all   In this case I fixed it by adding an exclude binding   public ActionResult Foo int id  int  page   Bind Exclude    MyField   MyModel model

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By default  MVC Controllers require a default constructor with no parameters  The simplest would be to make a default constructor that calls the one with parameters    public MyController     this new Helper         public MyController IHelper helper      this helper   helper      However  you can override this functionality by rolling your own ControllerFactory  This way you can tell MVC that when you are creating a MyController give it an instance of Helper   This allows you to use Dependency Injection frameworks with MVC  and really decouple everything  A good example of this is over at the StructureMap website  The whole quickstart is good  and he gets specific to MVC towards the bottom at  Auto Wiring

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I had the same problem   Just Removed HttpFileCollectionBase files from Post Action method argument  and added like HttpFileCollectionBase files   Request Files  in method body

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I added a parameterless constructor to the model inside of DOMAIN Folder  and the problem is solved     public User

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I just had a similar problem  The same exception occurs when a Model has no parameterless constructor   The call stack was figuring a method responsible for creating a new instance of a model      System Web Mvc DefaultModelBinder CreateModel ControllerContext controllerContext  ModelBindingContext bindingContext  Type modelType      Here is a sample   public class MyController   Controller       public ActionResult Action MyModel model                  public class MyModel       public MyModel IHelper helper     MVC cannot call that                                 public MyModel      MVC can call that

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I had the same problem     If your using a interface to decouple your connection against your DbContext  like me  you can use structuremap mvc  3 or 4 - nudget package  to be able to use a constructure in your controller class  This will give you a DependencyResolution folder  Just change the commented line with your For lt  InterfaceClass     and to Use lt  DbContextClass

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This error also occurs when using an IDependencyResolver  such as when using an IoC container  and the dependency resolver returns null  In this case ASP NET MVC 3 defaults to using the DefaultControllerActivator to create the object  If the object being created does not have a public no-args constructor an exception will then be thrown any time the provided dependency resolver has returned null   Here s one such stack trace    MissingMethodException  No parameterless constructor defined for this object      System RuntimeTypeHandle CreateInstance RuntimeType type  Boolean publicOnly  Boolean noCheck  Boolean amp  canBeCached  RuntimeMethodHandleInternal amp  ctor  Boolean amp  bNeedSecurityCheck   0    System RuntimeType CreateInstanceSlow Boolean publicOnly  Boolean skipCheckThis  Boolean fillCache   98    System RuntimeType CreateInstanceDefaultCtor Boolean publicOnly  Boolean skipVisibilityChecks  Boolean skipCheckThis  Boolean fillCache   241    System Activator CreateInstance Type type  Boolean nonPublic   69    System Web Mvc DefaultControllerActivator Create RequestContext requestContext  Type controllerType   67   InvalidOperationException  An error occurred when trying to create a controller of type  My Namespace MyController   Make sure that the controller has a parameterless public constructor      System Web Mvc DefaultControllerActivator Create RequestContext requestContext  Type controllerType   182    System Web Mvc DefaultControllerFactory GetControllerInstance RequestContext requestContext  Type controllerType   80    System Web Mvc DefaultControllerFactory CreateController RequestContext requestContext  String controllerName   74    System Web Mvc MvcHandler ProcessRequestInit HttpContextBase httpContext  IController amp  controller  IControllerFactory amp  factory   232    System Web Mvc  lt  gt c  DisplayClass6  lt BeginProcessRequest gt b  2    49    System Web Mvc  lt  gt c  DisplayClassb 1  lt ProcessInApplicationTrust gt b  a    13    System Web Mvc SecurityUtil  lt GetCallInAppTrustThunk gt b  0 Action f   7    System Web Mvc SecurityUtil ProcessInApplicationTrust Action action   22    System Web Mvc SecurityUtil ProcessInApplicationTrust Func 1 func   124    System Web Mvc MvcHandler BeginProcessRequest HttpContextBase httpContext  AsyncCallback callback  Object state   98    System Web Mvc MvcHandler BeginProcessRequest HttpContext httpContext  AsyncCallback callback  Object state   50    System Web Mvc MvcHandler System Web IHttpAsyncHandler BeginProcessRequest HttpContext context  AsyncCallback cb  Object extraData   16    System Web CallHandlerExecutionStep System Web HttpApplication IExecutionStep Execute    8963444    System Web HttpApplication ExecuteStep IExecutionStep step  Boolean amp  completedSynchronously   184

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First video on http   tekpub com conferences mvcconf  47 10 minutes in show the error and shows how to override the default ControllerFactory  I e  to create structure map controller factory   Basically  you are probably trying to implement dependency injection    The problem is that is the interface dependency

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I had same problem but later found adding any new interface and corresponding class requires it to be registered under Initializable Module for dependency injection  In my case it was inside code as follows    InitializableModule   ModuleDependency typeof EPiServer Web InitializationModule    public class DependencyResolverInitialization   IConfigurableModule        public void ConfigureContainer ServiceConfigurationContext context                context Container Configure ConfigureContainer           var structureMapDependencyResolver   new StructureMapDependencyResolver context Container           DependencyResolver SetResolver structureMapDependencyResolver           GlobalConfiguration Configuration Services Replace typeof IHttpControllerActivator   structureMapDependencyResolver              private void ConfigureContainer ConfigurationExpression container                container For lt IAppSettingService gt    Use lt AppSettingService gt             container For lt ISiteSettingService gt    Use lt SiteSettingService gt             container For lt IBreadcrumbBuilder gt    Use lt BreadcrumbBuilder gt             container For lt IFilterContentService gt    Use lt FilterContentService gt    Singleton            container For lt IDependecyFactoryResolver gt    Use lt DependecyFactoryResolver gt             container For lt IUserService gt    Use lt UserService gt             container For lt IGalleryVmFactory gt    Use lt GalleryVmFactory gt             container For lt ILanguageService gt    Use lt LanguageService gt             container For lt ILanguageBranchRepository gt    Use lt LanguageBranchRepository gt             container For lt ICacheService gt    Use lt CacheService gt              container For lt ISearchService gt    Use lt SearchService gt             container For lt IReflectionService gt    Use lt ReflectionService gt             container For lt ILocalizationService gt    Use lt LocalizationService gt             container For lt IBookingFormService gt    Use lt BookingFormService gt             container For lt IGeoService gt    Use lt GeoService gt             container For lt ILocationService gt    Use lt LocationService gt             RegisterEnterpriseAPIClient container             public void Initialize InitializationEngine context                   public void Uninitialize InitializationEngine context                   public void Preload string   parameters

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While this may be obvious to some  the culprit of this error for me was my MVC method was binding to a model that contained a property of type Tuple lt  gt   Tuple lt  gt  has no parameterless constructor

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Most probably you might have parameterized constructor in your controller and whatever dependency resolver you are using is not able to resolve the dependency properly  You need to put break-point where the dependency resolver method is written and you will get the exact error in inner exception

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I got same exception due to there was no parameterless public contructor  Code was like this   public class HomeController   Controller               private HomeController                  repo   new Repository            changed to    public class HomeController   Controller               public HomeController                  repo   new Repository            problem resolved to me

[asp.net-mvc] ASP.NET MVC: No parameterless constructor defined for this object

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