If I have the usual Edit actions, one for GET to retrieve an object by it's ID and to display it in an edit form. The next for POST to take the values in the ViewModel and update the object in the database.
public virtual ActionResult Edit(int id)
[HttpPost]
public ActionResult Edit(VehicleVariantEditSaveViewModel viewModel)
If an error occurs during model binding in the POST action, I understand I can RedirectToAction back to the GET action and preserve the ModelState validation errors by copying it to TempData and retrieving it after the redirect in the GET action.
if (TempData["ViewData"] != null)
{
ViewData = (ViewDataDictionary)TempData["ViewData"];
}
How do I then convert that ViewData, which includes the previous invalid ModelState, into a new model to send to the view so the user sees their invalid input with validation warnings? Oddly enough if I pass in a new instance of my ViewModel retrieved from the database (with the original valid data) to the View() this is ignored and the (invalid) data in the ViewData is displayed!
Thanks
I had a similar problem and decided to use the following pattern:
public ActionResult PersonalRecord(Guid id)
{
if (TempData["Model"] == null)
{
var personalRecord = _context.PersonalRecords.Single(p => p.UserId == id);
var model = personalRecord.ToPersonalRecordModel();
return View(model);
}
else
{
ViewData = (ViewDataDictionary) TempData["ViewData"];
return View(TempData["Model"]);
}
}
[HttpPost]
public ActionResult PersonalRecord(PersonalRecordModel model)
{
try
{
if (ModelState.IsValid)
{
var personalRecord = _context.PersonalRecords.Single(u => u.UserId == model.UserId);
personalRecord.Email = model.Email;
personalRecord.DOB = model.DOB;
personalRecord.PrimaryPhone = model.PrimaryPhone;
_context.Update(personalRecord);
_context.SaveChanges();
return RedirectToAction("PersonalRecord");
}
}
catch (DbEntityValidationException ex)
{
var errors = ex.EntityValidationErrors.First();
foreach (var propertyError in errors.ValidationErrors)
{
ModelState.AddModelError(propertyError.PropertyName, propertyError.ErrorMessage);
}
}
TempData["Model"] = model;
TempData["ViewData"] = ViewData;
return RedirectToAction("PersonalRecord", new { id = model.UserId });
}
Hope this helps.
I noticed that the Model is included in ViewData so you don't need to pass it in addition to the ViewData, what I don't understand is how you get at it to then return it to the view.
public ViewResult Edit(int id)
{
// Check if we have ViewData in the session from a previous attempt which failed validation
if (TempData["ViewData"] != null)
{
ViewData = (ViewDataDictionary)TempData["ViewData"];
}
VehicleVariantEditViewModel viewModel = new VehicleVariantControllerViewModelBuilder()
.BuildForEdit(id);
return View(viewModel);
}
The above works but obviously it's making an unnecessary call to the database to build a new Model (which gets automagically overwritten with the invalid values from the Model in the passed ViewData)
Confusing.
Related
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.
;)
how can i send data between actions with redirectAction??
I am using PRG pattern. And I want to make something like that
[HttpGet]
[ActionName("Success")]
public ActionResult Success(PersonalDataViewModel model)
{
//model ko
if (model == null)
return RedirectToAction("Index", "Account");
//model OK
return View(model);
}
[HttpPost]
[ExportModelStateToTempData]
[ActionName("Success")]
public ActionResult SuccessProcess(PersonalDataViewModel model)
{
if (!ModelState.IsValid)
{
ModelState.AddModelError("", "Error");
return RedirectToAction("Index", "Account");
}
//model OK
return RedirectToAction("Success", new PersonalDataViewModel() { BadgeData = this.GetBadgeData });
}
When redirect you can only pass query string values. Not entire complex objects:
return RedirectToAction("Success", new {
prop1 = model.Prop1,
prop2 = model.Prop2,
...
});
This works only with scalar values. So you need to ensure that you include every property that you need in the query string, otherwise it will be lost in the redirect.
Another possibility is to persist your model somewhere on the server (like a database or something) and when redirecting only pass the id which will allow to retrieve the model back:
int id = StoreModel(model);
return RedirectToAction("Success", new { id = id });
and inside the Success action retrieve the model back:
public ActionResult Success(int id)
{
var model = GetModel(id);
...
}
Yet another possibility is to use TempData although personally I don't recommend it:
TempData["model"] = model;
return RedirectToAction("Success");
and inside the Success action fetch it from TempData:
var model = TempData["model"] as PersonalDataViewModel;
You cannot pass data between actions using objects, as Darin mentioned, you can only pass scalar values.
If your data is too large, or does not consist only of scalar values, you should do something like this
[HttpGet]
public ActionResult Success(int? id)
{
if (!(id.HasValue))
return RedirectToAction("Index", "Account");
//id OK
model = LoadModelById(id.Value);
return View(model);
}
And pass that id from RedirectToAction
return RedirectToAction("Success", { id = Model.Id });
RedirectToAction method returns an HTTP 302 response to the browser, which causes the browser to make a GET request to the specified action. So you can not pass complex objects like you calling other methods with complex objects.
Your possible solution is to pass an id using with the GET action can build the object again. Some thing like this
[HttpPost]
public ActionResult SuccessProcess(PersonViewModel model)
{
//Some thing is Posted (P)
if(ModelState.IsValid)
{
//Save the data and Redirect (R)
return RedirectToAction("Index",new { id=model.ID});
}
return View(model)
}
public ActionResult Index(int id)
{
//Lets do a GET (G) request like browser requesting for any time with ID
PersonViewModel model=GetPersonFromID(id);
return View(id);
}
}
You can keep data (The complex object) between This Post and GET request using Session also (TempData is internally using session even). But i believe that Takes away the purity of PRG Pattern.
Here's my code:
[HttpGet]
public ActionResult Register()
{
RegisterViewModel model = new RegisterViewModel();
using (CityRepository city = new CityRepository())
{
model.SelectCityList = new SelectList(city.FindAllCities().ToList(), "CityID", "CityName");
}
using (CountryRepository country = new CountryRepository())
{
model.SelectCountryList = new SelectList(country.FindAllCountries().ToList(), "CountryID", "CountryName");
}
return View(model);
}
[HttpPost]
public ActionResult Register(RegisterViewModel model)
{
if (ModelState.IsValid)
{
//Actually register the user here.
RedirectToAction("Index", "Home");
}
//Something went wrong, redisplay the form for correction.
return View(model);
}
Is this the best approach or is there another better tested way? Keep in mind that my database tables/field names are nothing like what I declared in my models. I have to scrape the values from the ViewModel and put them into an entity framework generated class to persist the information.
Anything here that screams out at you as wrong?
I use that pattern and another pattern which looks like this (important part is the AutoMapper part):
[HttpPost]
public ActionResult Register(RegisterViewModel model)
{
if (!ModelState.IsValid)
{
// repopulate any input or other items set in GET
// prefer to do at top due to ^^^ is easy to overlook
return View(model);
}
// if it's an edit, pull to new instance
// from the database and use automapper to
// map over the submitted values from model to instance
// then update instance in database
//
// VALUE: useful if form only shows
// some of the properties/fields of model
// (otherwise, those not shown would be null/default)
// if it's new, insert
RedirectToAction("Index", "Home");
}
That's the pattern I generally use.
I prefer this pattern:
Controller:
[HttpGet]
public ActionResult Index()
{
var cities= (from m in db.cities select m);
ViewBag.Cities= cities;
var states = (from m in db.States select m);
ViewBag.States = states;
return View();
}
[HttpPost]
public ActionResult Index(RegisterViewModel model)
{
if (ModelState.IsValid)
{
// Saving the data
return View("ActionName", model);
}
return View();
}
View:
#Html.DropDownList("DDLCities",new SelectList(ViewBag.Cities, "CityId" , "CityName" ), new { #class = "className" })
#Html.DropDownList("DDLStates",new SelectList(ViewBag.States, "StateId" , "StateName" ), new { #class = "className" })
Advised changes to [HttpGet]:
[HttpGet]
public ActionResult Register()
{
// Get
var cities = new List<City>();
var countries = new List<Country>();
using (CityRepository city = new CityRepository())
{
cities = city.FindAllCities().ToList();
}
using (CountryRepository country = new CountryRepository())
{
counties = country.FindAllCountries().ToList();
}
// Map.
var aggregatedObjects = new SomePOCO(cities, countries);
var model = Mapper.Map<SomePOCO,RegisterViewModel>(aggregatedObjects );
// Return
return View(model);
}
Summary of changes:
Layout your logic in such a way the controller's job makes sense. Get - Map - Return. Exactly the tasks (in order) for which a Controller is designed for.
Use AutoMapper to do the heavy lifting of ViewModel creation for you.
Advised changes to your [HttpPost]:
[HttpPost]
public ActionResult Register(RegisterViewModel model)
{
if (!ModelState.IsValid)
return View(model);
try
{
var dbObj = Mapper.Map<RegisterViewModel,SomeDomainObj>(model);
_repository.Save(dbObj);
return RedirectToAction("Index");
}
catch (Exception exc)
{
if (exc is BusinessError)
ModelState.AddModelError("SomeKey", ((BusinessError)exc).FriendlyError);
else
ModelState.AddModelError("SomeKey", Resources.Global.GenericErrorMessage);
}
return View(model);
}
Summary of changes:
Try/catch. Always need to capture exceptions, whether they are domain exceptions or lower-level (database ones)
Check ModelState validity first. As #Cymen says - do it first so you don't forget later
Add exceptions to ModelState. Use custom exception classes for business errors with descriptive, resource-based messages. If the error is too low-level for the user (foreign key constraint, etc), show a generic message
I'm trying to create a very basic MVC app based on a tutorial. I am using the default routing, and simple Views and Model.
The problem I am having is with the HttpPost Edit function. I am expecting an object of my "MyObject" type to be passed as the parameter, but it always comes back null.
Here are my Edit functions from the controller (the Get function works properly):
public ActionResult Edit(int? id)
{
if (!id.HasValue)
return RedirectToAction("Index");
var item = (from obj in mDB.MyDatabaseObjects
where obj.Id == id
select obj).First();
return View(item);
}
//
// POST: /Main/Edit/5
[HttpPost]
public ActionResult Edit(MyDatabaseObject someObject)
{
var original = (from obj in mDB.MyDatabaseObjects
where obj.Id == someObject.Id
select obj).First();
if (!ModelState.IsValid)
return View(original);
mDB.ApplyCurrentValues(original.EntityKey.EntitySetName, someObject);
mDB.SaveChanges();
return RedirectToAction("Index");
}
Note that my (nearly identical) Create method works as expected:
[HttpPost]
public ActionResult Create([Bind(Exclude="Id")] MyDatabaseObject newObject)
{
if (!ModelState.IsValid)
return View();
int max = mDB.MyDatabaseObjects.Max(data => data.TaskOrder);
newObject.TaskOrder = max + 1;
mDB.AddToMyDatabaseObjects(newObject);
mDB.SaveChanges();
return RedirectToAction("Index");
}
Thanks,
wTs
Ensure the values on your view for MyDatabaseObject are inside of the form. Validate these values are being posted over - inspect Request.Form or use change the method signature to use
FormsCollection collection
simply to validate the values are getting posted. If its choosing that method - it should be matching the properties to the form field - its generally very simple.
I'm a beginner of MVC3 with ASP.Net (C#) but I don't get the next situation to delete a record.
I have a View that ask the user to confirm delete a item (record). As code I have this to initialize the view:
public ActionResult KeywordsDelete(Guid id)
{
_db = new BlaContext();
return _db.SearchTerms.Where(x => x.id.Equals(id)).First();
}
But when confirmed, then I have the next code.
[HttpPost]
public ActionResult KeywordsDelete(Guid id)
{
_db = new BlaContext();
var term = _db.SearchTerms.Where(x => x.id == id).First();
_db.SearchTerms.Remove(term);
_db.SaveChanges();
return View("Keywords", _db.SearchTerms.ToList());
}
Building is not possible because the signature of this method is already exists (same parameters and method name).
So I don't get how to delete a record in this situation. The view is created with a default Scaffold template (delete).
I found an alternative solution to this problem while reading up on MVC. Check out: Improving the Details and Delete Methods
[HttpPost, ActionName("Delete")]
public ActionResult DeleteConfirmed(int id = 0)
{
// Delete stuff...
}
This will route the action Delete to the method DeleteConfirmed.
You can give your post function another additional parameter
[HttpPost]
public ActionResult KeywordsDelete(Guid id, FormCollection collection)
{
_db = new BlaContext();
var term = _db.SearchTerms.Where(x => x.id == id).First();
_db.SearchTerms.Remove(term);
_db.SaveChanges();
return View("Keywords", _db.SearchTerms.ToList());
}
But your GET Action should also return a View not a data object, I think.
public ActionResult KeywordsDelete(Guid id)
{
_db = new BlaContext();
return View(_db.SearchTerms.Where(x => x.id.Equals(id)).First());
}