Can't find the proper solution to this problem.
I am using [Serializable] (MVC3 Futures) in order to have a "wizard" with separate views. Here is the code in my controller to serialize:
private MyViewModel myData;
protected override void OnActionExecuting(ActionExecutingContext filterContext)
{
var serialized = Request.Form["myData"];
if (serialized != null) //Form was posted containing serialized data
{
myData = (MyViewModel)new MvcSerializer().Deserialize(serialized, SerializationMode.Signed);
TryUpdateModel(myData);
}
else
myData = (MyViewModel)TempData["myData"] ?? new MyViewModel();
TempData.Keep();
}
protected override void OnResultExecuted(ResultExecutedContext filterContext)
{
if (filterContext.Result is RedirectToRouteResult)
TempData["myData"] = myData;
}
Further along in my controller I do something like this (just a snippet - code goes through wizard with next and back button strings):
public ActionResult Confirm(string backButton, string nextButton)
{
if (backButton != null)
return RedirectToAction("Details");
else if ((nextButton != null) && ModelState.IsValid)
return RedirectToAction("Submitted");
else
return View(myData);
}
In my .cshtml view, I have this:
#using (Html.BeginFormAntiForgeryPost())
{
#Html.Hidden("myData", new MvcSerializer().Serialize(Model, SerializationMode.Signed))
...
#Html.TextBoxFor(m => model.Step.EMail)
...
}
Because I am using dynamics, I have to use a variable instead in the view:
var model = (MyViewModel) Model.myData;
in order to do the #Html.TextBoxFor above. And herein lies my probelm, because if I do #model MyViewModel instead, then I can't do model.Step.EMail. But because of dynamics, the #Html.Hidden won't work and I get the following error:
Compiler Error Message: CS1973: 'System.Web.Mvc.HtmlHelper'
has no applicable method named 'Hidden' but appears to have an
extension method by that name. Extension methods cannot be dynamically
dispatched. Consider casting the dynamic arguments or calling the
extension method without the extension method syntax.
I can switch to some other way of doing this without [Serializable], but then I have to convert a LOT of code. Is there any way to make this work?
The extension method is not identifying the method because, the data type does not match.
Try cast as object.
#Html.Hidden("myData", new MvcSerializer().Serialize(Model, SerializationMode.Signed) as Object)
or
#Html.Hidden("myData", (Object)new MvcSerializer().Serialize(Model, SerializationMode.Signed))
It will works.
You can call
#(InputExtensions.Hidden(Html, "myData", new MvcSerializer().Serialize(Model, SerializationMode.Signed)))
instead of #Html.Hidden(...)
It is calling the extension method without the extension method syntax.
Related
I am looking for a method to switch from serializing data (which I originally did using Mvc Futures) and passing it around my controller actions to something that does not use serialize. My previous implementation was for a wizard that passed data from action to action until it was submitted and the data was saved. However, I am unable to use serialization in a new project and am looking for an alternative.
Here is an example of what I did in my controller:
private MyViewModel myViewModel;
protected override void OnActionExecuting(ActionExecutingContext filterContext)
{
var serialized = Request.Form["myViewModel"];
if (serialized != null) //Form was posted containing serialized data
{
myViewModel = (MyViewModel)new MvcSerializer()
.Deserialize(serialized, SerializationMode.Signed);
TryUpdateModel(myViewModel);
}
else
myViewModel= (MyViewModel)TempData["myViewModel"] ?? new MyViewModel();
TempData.Keep();
}
protected override void OnResultExecuted(ResultExecutedContext filterContext)
{
if (filterContext.Result is RedirectToRouteResult)
TempData["myViewModel"] = myViewModel;
}
Then in some actions:
// STEP 1:
public ActionResult Step1()
{
return View(myViewModel);
}
[HttpPost]
[ActionName("Step1")]
public ActionResult Step1POST(string nextButton)
{
if ((nextButton != null) && ModelState.IsValid)
return RedirectToAction("Step2");
return View(myViewModel);
}
// STEP 2:
[Themed]
public ActionResult Step2()
{
return View(myViewModel);
}
[HttpPost]
[ActionName("Step2")]
public ActionResult Step2POST(string backButton, string nextButton)
{
if (backButton != null)
return RedirectToAction("Step1");
else if ((nextButton != null) && ModelState.IsValid)
return RedirectToAction("Step3");
return View(myViewModel);
}
My view would contain this inside the #Html.BeginForm block:
#Html.Hidden("myViewModel",
new MvcSerializer().Serialize(Model, SerializationMode.Signed))
My first thought is that I have no other alternative (other than maybe jQuery, which I also cannot use right now). In this scenario I have to figure out how to use TempData in each ActionResult, which will get messy if I have 10 or so inputs in each view.
So my question would probably be two-fold:
Is there a clean alternative to using serialize in this manner?
If there is no clean alternative and I am forced to do it in each
ActionResult, I am not sure of how to do so if, for example, I kept
it to one input view and one submit/confirm view and just wanted to
pass two values to the "Submit" step (not shown above), such as
FirstName an EMail. How might I do that using TempData?
Thanks.
The website that I'm working on is heavily depending on ajax/json and knockout.js.
I would like to have a lot of my Controllers return view-tailored 'json objects', without wrapping them in a JsonResult when returning the method.
This would mean I could easily composite multiple calls into one parent object, but still be able to call the Actions separately too.
Simplified example:
public object Main(int groupId)
{
var viewModel = new
{
Persons = Employees(groupId),
Messages = AllMessages()
};
return viewModel;
}
public object Employees(int groupId)
{
return DatabaseContext.Employees.Where(e => e.GroupId == groupId).ToList();
}
public object AllMessages()
{
return DatabaseContext.Messages.ToList();
}
I was hoping I could capture the returned object in OnActionExecuted and at that point wrap the whole result up in a final JsonResult.
The result is already converted to a string and captured in a ContentResult though.
Any ideas? :) Thanks,
A good approach on this is to create helper methods for your entity calls. Or if you have those methods already somewhere, they can actually serve as the helper methods. In that manner you can return a list of strongly-typed Messages and Employees as well as returning your desired parent object. You can then have individual controller methods that returns json objects. In addition, you can extend the parent viewmodel to return additional fields.
The Parent ViewModel
public class ParentModel {
public Employee Persons {get;set;}
public Message Messages {get;set;}
}
The Helper Methods
The beauty of using helper methods similar to what is defined here is that you can apply a few more logic to your query, and more, and you don't have to change anything in your controller methods.
public ParentModel GetMain(int groupId)
{
var viewModel = new ParentModel
{
Persons = Employees(groupId),
Messages = AllMessages()
};
return viewModel;
}
public IEnumerable<Employee> Employees(int groupId)
{
return DatabaseContext.Employees.Where(e => e.GroupId == groupId).ToList();
}
public IEnumerable<Message> AllMessages()
{
return DatabaseContext.Messages.ToList();
}
The Controller Methods
public ActionResult GetParent(int groupId){
return Json(helperinstance.GetMain());
}
public ActionResult GetEmployees(int groupId){
return Json(helperinstance.Employees());
}
public ActionResult GetMessages(int groupId){
return Json(helperinstance.AllMessages());
}
Thanks for the answer. I'm not going for the solution of von v. because I like to keep the boilerplate as small as possible.
In the end I am trying out the following approach. It seems to work pretty well for now, but I still have to test it in real production.
If anyone has some (security) concerns with this, I'm happy to hear them in the comments.
// BaseController
protected override void OnActionExecuting(ActionExecutingContext filterContext)
{
var returnType = ((ReflectedActionDescriptor)filterContext.ActionDescriptor).MethodInfo.ReturnType;
// is the returnType not deriving from ActionResult? Automatically wrap it in a JsonResult
if ( !typeof(ActionResult).IsAssignableFrom(returnType) )
{
var result = filterContext.ActionDescriptor.Execute(filterContext, filterContext.ActionParameters);
filterContext.Result = Json( result );
}
}
I have a base Controller like follow
public abstract class BaseController
{
protected ActionResult LogOn(LogOnViewModel viewModel)
{
SaveTestCookie();
var returnUrl = "";
if (HttpContext != null && HttpContext.Request != null && HttpContext.Request.UrlReferrer != null)
{
returnUrl = HttpContext.Request.UrlReferrer.LocalPath;
}
TempData["LogOnViewModel"] = viewModel;
return RedirectToAction("ProceedLogOn", new { returnUrl });
}
public ActionResult ProceedLogOn(string returnUrl)
{
if (CookiesEnabled() == false)
{
return RedirectToAction("logon", "Account", new { area = "", returnUrl, actionType, cookiesEnabled = false });
}
var viewModel = TempData["LogOnViewModel"] as LogOnViewModel;
if (viewModel == null)
{
throw new NullReferenceException("LogOnViewModel is not found in tempdata");
}
//Do something
//the problem is I missed the values which are set in the ViewBag
}
}
and another Controller
public class MyController : BaseController
{
[HttpPost]
public ActionResult LogOn(LogOnViewModel viewModel)
{
// base.LogOn is used in differnet controller so I saved some details in view bag
ViewBag.Action = "LogonFromToolbar";
ViewBag.ExtraData = "extra data related only for this action";
return base.LogOn(viewModel);
}
}
the problem is I missed the view bag values in ProceedLogOn action method.
I have the values in Logon method in BaseController.
How can I copy the values of ViewBag from one Action to another Action?
So I can not simply say this.ViewBag=ViewBag;
because ViewBag doesn't have setter. I was thinking of Iterating through viewbag.
I tried ViewBag.GetType().GetFields() and ViewBag.GetType().GetProperties() but they return nothing.
ViewData reflects ViewBag
You can iterate the values you've stored like this :
ViewBag.Message = "Welcome to ASP.NET MVC!";
ViewBag.Answer = 42;
foreach (KeyValuePair<string, object> item in ViewData)
{
// if (item.Key = "Answer") ...
}
This link should also be useful
I'm afraid I don't have the answer how to copy ViewBag.
However, I would never use ViewBag that way.
ViewBag is some data the Controller gives to the View to render output if someone does not like to use ViewModel for some reasons. The View should never know anything about the Controller but your ViewBag is holding a ActionName ;).
Anyway, the ProceedLogOn action method has pretty much parameters which is ... not a nice code actually so why hesitate to add more parameters which are currently being hold in MyController.Logon ViewBag? Then inside method ProceedLogOn you have what you want.
;)
I need some help with this error "The ObjectContext instance has been disposed and can no longer be used for operations that require a connection."
It's a asp.net mvc3, EF4, and ms sql.
Here is the razor with two dropdowns:
<div class="editRow">
#Html.DropDownListFor(m=>m.IndustryId, (SelectList)ViewBag.Industry, #Empower.Resource.General.ddlDefaultVal, new { #class = "ddl400" })
#Html.ValidationMessageFor(m => m.IndustryId)
</div>
<div class="editRow">
#Html.DropDownListFor(m=>m.ProvinceId, (SelectList)ViewBag.Province, #Empower.Resource.General.ddlDefaultVal, new {#class = "ddl400"})
#Html.ValidationMessageFor(m => m.ProvinceId)
</div>
Controller:
IndustryService indService = new IndustryService();
ViewBag.Industry = new SelectList(indService.GetAllIndustry(), "IndustryId", "IndustryName");
ProvinceService proService = new ProvinceService();
ViewBag.Province = new SelectList(proService.GetAllProvince(), "ProvinceId", "ProvinceName");
return View();
ProvinceService:
public IEnumerable<Province> GetAllProvince()
{
using (var context = DBContext.ObjectContext)
{
var pros = context.Provinces;
return pros;
}
}
IndustryService is identical as above...
public class DBContext
{
private static EmpowerDBEntities _empowerContext;
public static EmpowerDBEntities ObjectContext
{
get
{
if (_empowerContext == null)
_empowerContext = new EmpowerDBEntities();
return _empowerContext;
}
}
}
I know the problem occurs in second dropdown when it tries to retrive data while the connection is desposed by previous query. Please help me with this, thanks.
The fix is simple - convert to a .ToList() or First() before using. LINQ has deferred execution and tries to run this command after the context is disposed (when your object results are referenced) - not when you actually make the call.. You need to force it to run now while the context is in scope.
using (var context = DBContext.ObjectContext)
{
var pros = context.Provinces;
return pros.ToList();
}
Also - your code above is checking for null in the get accessor. However this object won't be null - it will be disposed, so you cannot do your check this way, you need to check if its null and not disposed.
public class DBContext
{
private static EmpowerDBEntities _empowerContext;
public static EmpowerDBEntities ObjectContext
{
get
{
if (_empowerContext == null || _empowerContext.IsDisposed())
_empowerContext = new EmpowerDBEntities();
return _empowerContext;
}
}
}
something like that anyways :)
I ran into a similar problem. I had been following this pattern, which I had seen in many code examples on the web:
public ActionResult Show(int id)
{
using (var db = new MyDbContext())
{
var thing = db.Things.Find(id);
return View(thing);
}
}
However, this was causing the ObjectDisposedException listed above whenever I tried to access anything that hadn't been loaded into memory in the View code (in particular, one-to-many relationships in the main view model).
I found a different pattern in this example:
public class MyController : Controller
{
private MyDbContext _db;
public MyController()
{
_db = new MyDbContext();
}
public ActionResult Show(int id)
{
// Do work such as...
var thing = _db.Things.Find(id);
return View(thing);
}
protected override void Dispose(bool disposing)
{
_db.Dispose();
base.Dispose(disposing);
}
}
This pattern keeps the database connection alive until the View has finished rendering, and neatly disposes of it when the Controller itself is disposed.
Here is the problem when you are using
using(var context=new CustomerContext())
{
return View(context.Customers.ToList());
}
when the block of code executes all references are disposed that you are lazzy loading so that's why it is throwing this error.
so i used
return View(context.Customers.ToList()) directly it will work perfectly fine.
In my MVC website, I am creating a small forum. For a single post I am rendering my "Single(Post post)" action in my "PostController" like below
<% Html.RenderAction<PostController>(p => p.Single(comment)); %>
Also When a user reply a post I am sending reply as an ajax request to my "CreatePost" action then return "Single" view as result of this action like below
public ActionResult CreatePostForForum(Post post)
{
//Saving post to DB
return View("Single", postViewData);
}
When I do like that only the view is being rendered, Codes in "Single" Actions body isn't beig executed.
What is the best way to do this?
Also I want to return "Single" action result as string in my JsonObject like below
return Json(new{IsSuccess = true; Content= /*HERE I NEED Single actions result*/});
You can use something like this, but be very careful with this. It can actually cause badly traceable errors (for example when you forget to explicitly set view name in Single method).
public ActionResult Single(PostModel model) {
// it is important to explicitly define which view we should use
return View("Single", model);
}
public ActionResult Create(PostModel model) {
// .. save to database ..
return Single(model);
}
Cleaner solution would be to do the same as if it was post from standard form - redirect (XMLHttpRequest will follow it)
For returning ajax views wrapped in json I use following class
public class AjaxViewResult : ViewResult
{
public AjaxViewResult()
{
}
public override void ExecuteResult(ControllerContext context)
{
if (!context.HttpContext.Request.IsAjaxRequest())
{
base.ExecuteResult(context);
return;
}
var response = context.HttpContext.Response;
response.ContentType = "application/json";
using (var writer = new StringWriter())
{
var oldWriter = response.Output;
response.Output = writer;
try
{
base.ExecuteResult(context);
}
finally
{
response.Output = oldWriter;
}
JavaScriptSerializer serializer = new JavaScriptSerializer();
response.Write(serializer.Serialize(new
{
action = "replace",
html = writer.ToString()
}));
}
}
}
It is probably not the best solution, but it works quite well. Note that you will need to manually set View, ViewData.Model, ViewData, MasterName and TempData properties.
My recommendation:
Post your forum reply (and whatever options) via Ajax.
Return your JSONResult, using this method: ASP MVC View Content as JSON to render your content.
In the OnSuccess handler of your ajax call, check if IsSuccess is true. If successful, append the content to the appropriate container using JQuery