ASP.NET MVC3/Razor newbie question:
I am setting up a model with custom validation. While the properties that I decorate with things like [Required] and [RegularExpression(...)] are performing as expected, I'm finding that the custom validation is not working. I made my model implement IValidatableObject, and I can hit a breakpoint inside the Validate() method and watch the method doing a yield return new ValidationResult(...); - but the form nonetheless gets posted.
Is there some secret switch that I'm missing?
If you are talking about server side validation, do you have the ModelState.Isvalid check?
http://weblogs.asp.net/scottgu/archive/2010/01/15/asp-net-mvc-2-model-validation.aspx
The form will be posted when you use IValidatableObject to validate model properties. As Joeri Jans says, you can still prevent this and return the page to the user during your action method:
public ActionResult MyAction(MyModel model)
{
if (ModelState.IsValid)
{
// code to perform action when input is valid
return [return something]
}
return View(model); // re-display form because ModelState.IsValid == false
}
If you want your custom validation to prevent the form from being posted, you need to validate on the client. The easiest way to do this is with the RemoteAttribute.
public class MyModel
{
[Remote("MyValidateAction", "MyController", HttpMethod = "POST")]
public string MyProperty { get; set; }
}
You can still keep your code in IValidatableObject, and validate it from an action method like so:
[HttpPost]
public virtual JsonResult MyValidateAction(string myProperty)
{
var model = new MyModel{ MyProperty = myProperty, };
var results = new List<ValidationResult>();
var isValid = Validator.TryValidateObject(model,
new ValidationContext(model, null, null), results, true);
return isValid
? Json(true)
: Json(results[0].ErrorMessage);
}
The above action method does virtually the same thing as the default model binder. It constructs an instance of your viewmodel, then validates it. All validation rules will be checked, including your IValidatableObject code. If you need to send more properties to the action method for the construction of your viewmodel, you can do so with the AdditionalFields property of the RemoteAttribute.
Hope this helps.
Related
I have this issue since yesterday.
In my User model I have a [NotMapped] called "ConfirmPassword". I don´t save it on the database but I use it on my Create form as a always to validate the data input for new users.
Since than, it´s ok. The problem is on my [HttpPost] Edit action. I should be able to edit some user's data without type and confirm the password. I use both Password and ConfirmPassword as a way to confirm the old password and informe the new one, if I wanna change the password. But, if I don´t, I leave them blank.
I have used already the code below to be able to pass the ModelState.IsValid() condition and it worked:
ModelState["Password"].Errors.Clear();
ModelState["ConfirmPassword"].Errors.Clear();
But, just before the db.SaveChanges(), as User user view model is considered, it has both properties empty and I got:
Property: ConfirmPassword Error: The field ConfirmPassword is invalid.
The question is: How could I skip de Required model validation when I want to update an object?
I read already about custom ModelValidations with classes extending ValidationAttribute and
DataAnnotationsModelValidator but I am not doing it right.
Any idea? How could I create a custom model validation that checks if the UserId property is null or not. It´s a nice way to check if I'm in Create or Edit action.
Thanks,
Paulo
Using the domain objects as your ViewModel will leads you to a condition of less scalability. I would opt for seperate ViewModels specific for the Views. When i have to save the data i map the ViewModel to the Domain model and save that. In your speciific case, i would create 2 ViewModels
public class CustomerViewModel
{
public string FirstName { set;get;}
public string LastName { set;get;}
}
And i will Have another ViewModel which inherits from the above class, for the Create View
public class CustomerCreateViewModel :CustomerViewModel
{
[Required]
public string Password { set;get;}
[Required]
public string ConfirmPassword { set;get;}
}
Now in my Get actions, i use this ViewModel
public ActionResult Create()
{
var vm=new CustomerCreateViewModel();
return View(vm);
}
and of course my View(create.cshtml) is now binded to this ViewModel
#model CustomerCreateViewModel
<h2>Create Csustomer</h2/>
//Other form stuff
Similarly for My Edit Action,
public ActionResult Edit(int id)
{
var vm=new CustomerViewModel();
var domainCustomer=repo.GetCustomerFromID(id);
if(domainCustomer!=null)
{
//This manual mapping can be replaced by AutoMapper.
vm.FirstName=domainCustomer.FirstName;
vm.LastName=domainCustomer.LastName;
}
return View(vm);
}
This view is bounded to CustomerViewModel
#model CustomerViewModel
<h2>Edit Info of #Model.FirstName</h2>
//Other form stuff
In your POST Actions, Map it back to the Domain object and Save
[HttpPost]
public ActionResult Create(CustomerCreateViewModel model)
{
if(ModelState.IsValid)
{
var domainCust=new Customer();
domainCust.FirstName=model.FirstName;
repo.InsertCustomer(domainCust);
//Redirect if success (to follow PRG pattern)
}
return View(model);
}
Instead of writing the Mapping yourself, you may consider using AutoMapper library to do it for you.
My model contains a string field called "longdescription" which gets the value of the tinymce editor's content
Public class ArticleModel:BaseModel{
[StringLength(8000, ErrorMessage = "Long description must be in 8000 characters or less"), AllowHtml]
public string LongDescription { get; set; }
}
Here is my controller code
[HttpPost]
public ActionResult AddEdit(ArticleModel model)
{
string buttonName = Request.Form["Button"];
if (buttonName == "Cancel")
return RedirectToAction("Index");
// something failed
if (!ModelState.IsValid)
{
}
// Update the articles
}
My problem is when I use Request.Form to access the post value, it's working fine without throwing "A potentially dangerous...." error, but when I use Request.Params["Button"], it threw that errors. Is something I am missing?
Thanks
Updated
Sorry the answer Adam gave doesn't really answer my question. Can anyone give more suggestion?
Ideally you shouldn't really be using either. Those are more Web Forms centric values even though they 'can' be used.
Either pass in a FormsCollection item and check it there using collection["Button"] or even better - your cancel button itself should probably just do the redirect. Why post when you do nothing but redirect?
In your view you can emit the url via Url.Action() and put that into your button's click handler (client side)
It is the HttpRequest.Params getter that is throwing this exception. This getter basically builds and returns a key/value pair collection which is the aggregation of the QueryString, Form, Cookies and ServerVariables collections in that order. Now what is important is that when you use this getter it will always perform request validation and this no matter whether you used the [AllowHtml] attribute on some model property or if you decorated the controller action with the [ValidateInput(false)] attribute and disabled all input validation.
So this is not really a bug in the AllowHtml attribute. It is how the Params property is designed.
As #Adam mentioned in his answer you should avoid accessing request values manually. You should use value providers which take into account things such as disabled request validation for some fields.
So simply add another property to your view model:
public class ArticleModel: BaseModel
{
[StringLength(8000, ErrorMessage = "Long description must be in 8000 characters or less")]
[AllowHtml]
public string LongDescription { get; set; }
public string Button { get; set; }
}
and then in your controller action:
[HttpPost]
public ActionResult AddEdit(ArticleModel model)
{
string buttonName = model.Button;
if (buttonName == "Cancel")
{
return RedirectToAction("Index");
}
// something failed
if (!ModelState.IsValid)
{
}
// Update the articles
}
I need to do late binding of a complex type with DataAnnotations within an Action if condition X is true. I cant bind everything up front in the method params as a couple of them will not exist unless X == true so Model.IsValid will be false (since it tried to bind non existant params) due to validation failing on the complex type.
MonoRail solved this by allowing you to manually bind when needed, this is the exact scenario i have so im wondering if theres something similar available in MVC3?
I cant overload the Action as it blows up with an ambiguous call, i cant post to a different action as the form is all dynamic content, so i see the only alternative is rolling my own validation / binding mechanism pulling out data annotations to validate with.... boooo :(
I think what you need is the ControllerBase.TryUpdateModel method (it has a lots of overloads).
You can use it similarly like BindObject:
Some model:
public class MyModel
{
[Required]
public string Name { get; set; }
public string Description { get; set; }
}
In the controller action:
[HttpPost]
public ActionResult UpdateModel(bool? acceptedConditions)
{
var model = new MyModel();
if (acceptedConditions ?? false)
{
if (TryUpdateModel(model))
{
//Do something when the model is valid
}
else
{
//Do something else when the model is invalid
}
}
return View();
}
Could any body explain, when to use
TempData
ViewBag
ViewData
I have a requirement, where I need to set a value in a controller one, that controller will redirect to Controller Two and Controller Two will render the View.
I have tried to use ViewBag, the value gets lost by the time I reach Controller Two.
Can I know when to use and advantages or disadvantages?
Thanks
1)TempData
Allows you to store data that will survive for a redirect. Internally it uses the Session as backing store, after the redirect is made the data is automatically evicted. The pattern is the following:
public ActionResult Foo()
{
// store something into the tempdata that will be available during a single redirect
TempData["foo"] = "bar";
// you should always redirect if you store something into TempData to
// a controller action that will consume this data
return RedirectToAction("bar");
}
public ActionResult Bar()
{
var foo = TempData["foo"];
...
}
2)ViewBag, ViewData
Allows you to store data in a controller action that will be used in the corresponding view. This assumes that the action returns a view and doesn't redirect. Lives only during the current request.
The pattern is the following:
public ActionResult Foo()
{
ViewBag.Foo = "bar";
return View();
}
and in the view:
#ViewBag.Foo
or with ViewData:
public ActionResult Foo()
{
ViewData["Foo"] = "bar";
return View();
}
and in the view:
#ViewData["Foo"]
ViewBag is just a dynamic wrapper around ViewData and exists only in ASP.NET MVC 3.
This being said, none of those two constructs should ever be used. You should use view models and strongly typed views. So the correct pattern is the following:
View model:
public class MyViewModel
{
public string Foo { get; set; }
}
Action:
public Action Foo()
{
var model = new MyViewModel { Foo = "bar" };
return View(model);
}
Strongly typed view:
#model MyViewModel
#Model.Foo
After this brief introduction let's answer your question:
My requirement is I want to set a value in a controller one, that
controller will redirect to ControllerTwo and Controller2 will render
the View.
public class OneController: Controller
{
public ActionResult Index()
{
TempData["foo"] = "bar";
return RedirectToAction("index", "two");
}
}
public class TwoController: Controller
{
public ActionResult Index()
{
var model = new MyViewModel
{
Foo = TempData["foo"] as string
};
return View(model);
}
}
and the corresponding view (~/Views/Two/Index.cshtml):
#model MyViewModel
#Html.DisplayFor(x => x.Foo)
There are drawbacks of using TempData as well: if the user hits F5 on the target page the data will be lost.
Personally I don't use TempData neither. It's because internally it uses Session and I disable session in my applications. I prefer a more RESTful way to achieve this. Which is: in the first controller action that performs the redirect store the object in your data store and user the generated unique id when redirecting. Then on the target action use this id to fetch back the initially stored object:
public class OneController: Controller
{
public ActionResult Index()
{
var id = Repository.SaveData("foo");
return RedirectToAction("index", "two", new { id = id });
}
}
public class TwoController: Controller
{
public ActionResult Index(string id)
{
var model = new MyViewModel
{
Foo = Repository.GetData(id)
};
return View(model);
}
}
The view stays the same.
TempData
Basically it's like a DataReader, once read, data will be lost.
Check this Video
Example
public class HomeController : Controller
{
public ActionResult Index()
{
ViewBag.Message = "Welcome to ASP.NET MVC!";
TempData["T"] = "T";
return RedirectToAction("About");
}
public ActionResult About()
{
return RedirectToAction("Test1");
}
public ActionResult Test1()
{
String str = TempData["T"]; //Output - T
return View();
}
}
If you pay attention to the above code, RedirectToAction has no impact over the TempData until TempData is read. So, once TempData is read, values will be lost.
How can i keep the TempData after reading?
Check the output in Action Method Test 1 and Test 2
public class HomeController : Controller
{
public ActionResult Index()
{
ViewBag.Message = "Welcome to ASP.NET MVC!";
TempData["T"] = "T";
return RedirectToAction("About");
}
public ActionResult About()
{
return RedirectToAction("Test1");
}
public ActionResult Test1()
{
string Str = Convert.ToString(TempData["T"]);
TempData.Keep(); // Keep TempData
return RedirectToAction("Test2");
}
public ActionResult Test2()
{
string Str = Convert.ToString(TempData["T"]); //OutPut - T
return View();
}
}
If you pay attention to the above code, data is not lost after RedirectToAction as well as after Reading the Data and the reason is, We are using TempData.Keep(). is that
In this way you can make it persist as long as you wish in other controllers also.
ViewBag/ViewData
The Data will persist to the corresponding View
ViewBag, ViewData, TempData and View State in MVC
http://royalarun.blogspot.in/2013/08/viewbag-viewdata-tempdata-and-view.html
ASP.NET MVC offers us three options ViewData, VieBag and TempData for passing data from controller to view and in next request. ViewData and ViewBag are almost similar and TempData performs additional responsibility.
Similarities between ViewBag & ViewData :
Helps to maintain data when you move from controller to view. Used to
pass data from controller to corresponding view. Short life means
value becomes null when redirection occurs. This is because their goal
is to provide a way to communicate between controllers and views. It’s
a communication mechanism within the server call.
Difference between ViewBag & ViewData:
ViewData is a dictionary of objects that is derived from
ViewDataDictionary class and accessible using strings as keys. ViewBag
is a dynamic property that takes advantage of the new dynamic features
in C# 4.0. ViewData requires typecasting for complex data type and
check for null values to avoid error. ViewBag doesn’t require
typecasting for complex data type.
ViewBag & ViewData Example:
public ActionResult Index()
{
ViewBag.Name = "Arun Prakash";
return View();
}
public ActionResult Index()
{
ViewData["Name"] = "Arun Prakash";
return View();
}
In View, we call like below:
#ViewBag.Name
#ViewData["Name"]
TempData:
Helps to maintain data when you move from one controller to other
controller or from one action to other action. In other words when you
redirect, “Tempdata” helps to maintain data between those redirects.
It internally uses session variables. TempData is meant to be a very
short-lived instance, and you should only use it during the current
and the subsequent requests only
The only scenario where using TempData will reliably work is when you are redirecting. This is because a redirect kills the current request (and sends HTTP status code 302 Object Moved to the client), then creates a new request on the server to serve the redirected view.
It requires typecasting for complex data type and check for null values to avoid error.
public ActionResult Index()
{
var model = new Review()
{
Body = "Start",
Rating=5
};
TempData["ModelName"] = model;
return RedirectToAction("About");
}
public ActionResult About()
{
var model= TempData["ModelName"];
return View(model);
}
void Keep()
Calling this method with in the current action ensures that all the items in TempData are not removed at the end of the current request.
#model MyProject.Models.EmpModel;
#{
Layout = "~/Views/Shared/_Layout.cshtml";
ViewBag.Title = "About";
var tempDataEmployeet = TempData["emp"] as Employee; //need typcasting
TempData.Keep(); // retains all strings values
}
void Keep(string key)
Calling this method with in the current action ensures that specific item in TempData is not removed at the end of the current request.
#model MyProject.Models.EmpModel;
#{
Layout = "~/Views/Shared/_Layout.cshtml";
ViewBag.Title = "About";
var tempDataEmployeet = TempData["emp"] as Employee; //need typcasting
TempData.Keep("emp"); // retains only "emp" string values
}
TempData
will be always available until first read, once you read it its not available any more can be useful to pass quick message also to view that will be gone after first read.
ViewBag
Its more useful when passing quickly piece of data to the view, normally you should pass all data to the view through model , but there is cases when you model coming direct from class that is map into database like entity framework
in that case you don't what to change you model to pass a new piece of data, you can stick that into the viewbag
ViewData is just indexed version of ViewBag and was used before MVC3
Also the scope is different between viewbag and temptdata. viewbag is based on first view (not shared between action methods) but temptdata can be shared between an action method and just one another.
I have an Action like this:
Update([Bind(Prefix = "CurrentModel")] dynamic edited)
but when I use dynamic the ModelState.IsValid always returns true so it seems like there is no validation on the dynamic object? If not, how can I solve this?
There are two cases:
You are using view models as action arguments in which case the default model binder automatically assigns the properties and sets possible errors to the model state:
public ActionResult Update([Bind(Prefix = "CurrentModel")] EditViewModel edited)
{
if (ModelState.IsValid)
{
}
...
}
You are using some weak typing with either dynamic or FormCollection in which case the default model binder doesn't kick in and doesn't perform any validation at all as it is not capable of infering your real model type. In this case you need to manually call TryUpdateModel and indicate your model type:
public ActionResult Update(dynamic edited)
{
var model = new MyViewModel();
if (!TryUpdateModel(model, "CurrentModel"))
{
// The model was not valid
}
...
}
Conclusion: using dynamic as action argument in a controller action makes very little sense.