Question

I have the following PagedListModel:

public class PagedClientViewModel
{
    public int? Page { get; set; }
    public PagedList.IPagedList<ClientViewModel> Clients { get; set; }               
}

public class ClientViewModel
{        
    public string ClientNumber { get; set; }
    public bool UseThisClient{ get; set; }
}

My view looks like this:

@using (Html.BeginForm("Index", "Home", FormMethod.Get, new { id = "Form" }))
{
    @foreach (var item in Model.Clients)
    {
       @Html.DisplayFor(modelItem => item.ClientNumber)
       @Html.CheckBoxFor(modelItem => item.UseThisClient)
    }    

 @Html.HiddenFor(model => model.Clients)            
}

Controller Action:

 public ActionResult Index(PagedClientViewModel model)
 {
  //...process all clients in the list
 }

I want to post the model back to the controller so that I can process which checkboxes have been ticked, but I get the following error: I kind of understand that the error is because I’m posting back an interface but I cant find a way around that. How can I get this work?

Cannot create an instance of an interface. at
System.RuntimeTypeHandle.CreateInstance(RuntimeType type, Boolean
publicOnly, Boolean noCheck, Boolean& canBeCached,
RuntimeMethodHandleInternal& ctor, Boolean& bNeedSecurityCheck) at
System.RuntimeType.CreateInstanceSlow(Boolean publicOnly, Boolean
skipCheckThis, Boolean fillCache, StackCrawlMark& stackMark) at
System.RuntimeType.CreateInstanceDefaultCtor(Boolean publicOnly,
Boolean skipCheckThis, Boolean fillCache, StackCrawlMark& stackMark)
at System.Activator.CreateInstance(Type type, Boolean nonPublic)
at System.Activator.CreateInstance(Type type) at
System.Web.Mvc.DefaultModelBinder.CreateModel(ControllerContext
controllerContext, ModelBindingContext bindingContext, Type modelType)
at System.Web.Mvc.DefaultModelBinder.BindSimpleModel(ControllerContext
controllerContext, ModelBindingContext bindingContext,
ValueProviderResult valueProviderResult) at
System.Web.Mvc.DefaultModelBinder.BindModel(ControllerContext
controllerContext, ModelBindingContext bindingContext) at
System.Web.Mvc.DefaultModelBinder.GetPropertyValue(ControllerContext
controllerContext, ModelBindingContext bindingContext,
PropertyDescriptor propertyDescriptor, IModelBinder propertyBinder)
at System.Web.Mvc.DefaultModelBinder.BindProperty(ControllerContext
controllerContext, ModelBindingContext bindingContext,
PropertyDescriptor propertyDescriptor) at
System.Web.Mvc.DefaultModelBinder.BindProperties(ControllerContext
controllerContext, ModelBindingContext bindingContext) at
System.Web.Mvc.DefaultModelBinder.BindComplexElementalModel(ControllerContext
controllerContext, ModelBindingContext bindingContext, Object model)
at
System.Web.Mvc.DefaultModelBinder.BindComplexModel(ControllerContext
controllerContext, ModelBindingContext bindingContext) at
System.Web.Mvc.DefaultModelBinder.BindModel(ControllerContext
controllerContext, ModelBindingContext bindingContext) at
System.Web.Mvc.ControllerActionInvoker.GetParameterValue(ControllerContext
controllerContext, ParameterDescriptor parameterDescriptor) at
System.Web.Mvc.ControllerActionInvoker.GetParameterValues(ControllerContext
controllerContext, ActionDescriptor actionDescriptor) at
System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c_DisplayClass25.b_1e(AsyncCallback
asyncCallback, Object asyncState) at
System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult1.Begin(AsyncCallback
callback, Object state, Int32 timeout) at
System.Web.Mvc.Async.AsyncControllerActionInvoker.BeginInvokeAction(ControllerContext
controllerContext, String actionName, AsyncCallback callback, Object
state) at
System.Web.Mvc.Controller.<>c__DisplayClass1d.<BeginExecuteCore>b__17(AsyncCallback
asyncCallback, Object asyncState) at
System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult1.Begin(AsyncCallback
callback, Object state, Int32 timeout) at
System.Web.Mvc.Controller.BeginExecuteCore(AsyncCallback callback,
Object state) at
System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult1.Begin(AsyncCallback
callback, Object state, Int32 timeout) at
System.Web.Mvc.Controller.BeginExecute(RequestContext requestContext,
AsyncCallback callback, Object state) at
System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.BeginExecute(RequestContext
requestContext, AsyncCallback callback, Object state) at
System.Web.Mvc.MvcHandler.<>c__DisplayClass8.<BeginProcessRequest>b__2(AsyncCallback
asyncCallback, Object asyncState) at
System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult1.Begin(AsyncCallback
callback, Object state, Int32 timeout) at
System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContextBase
httpContext, AsyncCallback callback, Object state) at
System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContext httpContext,
AsyncCallback callback, Object state) at
System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.BeginProcessRequest(HttpContext
context, AsyncCallback cb, Object extraData) at
System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
at System.Web.HttpApplication.ExecuteStep(IExecutionStep step,
Boolean& completedSynchronously)

Answer 1

Work around for this problem is to pass the paging meta data as separate property and reconstruct the IPagedList in the view. Like below

public class PagedClientViewModel
{
    public int? Page { get; set; }
    public List<ClientViewModel> Clients { get; set; }
    public IPagedList PagingMetaData { get; set; } 
}

gererating th metadata

pagedClientViewModel.PagingMetaData = new StaticPagedList<ClientViewModel>(pagedClientViewModel.Clients, pageIndex, pageSize, TotalClients).GetMetaData();

constructing the pager in the view

<div style="text-align: center">
    @Html.PagedListPager(new StaticPagedList<ClientViewModel>(Model.Clients, Model.PagingMetaData), page => Url.Action("<actionname>", new { page }), PagedListRenderOptions.Classic)
</div>