I just start do work on MVC4 Asp.Net
I have this class in my models
namespace PhoneBook.Models
{
public class User
{
public string Username { get; set; }
public string Password { get; set; }
public static String writeasd(){
return "asd";}
}
I have this method in my controller:
public ActionResult Main()
{
ViewBag.Username = Request.Form["username"];
ViewBag.Password = Request.Form["password"];
var user = new User()
return View(user);
}
However when I tried to call this method from my view like this:
#User.writeasd()
It gives error. What is the problem? Can you help me?
Note : I have #using PhoneBook.Models in the beginning of my view
When using a strongly typed view as you are there, you need two things.
One is a model directive
#model PhoneBook.Models.User
Then you can reference your model using the Model property of the view page.
So in your instance, you would use
#Model.writeasd()
HTH
Related
I am trying to write a specific value to a page in ASP.NET Core 6. I found multiple solutions with iterators but I am not able to write a single value from non-iteratable models / instances (no enumerators & lists) to a page.
public class UserViewModel
{
public string Id { get; set; }
public string UserName { get; set; }
public string Email { get; set; }
}
This models purpose is to get filled with values from the Identity Framework.
public UserViewModel umodel { get; set; }
Said model gets instanced, filled without any problems - it holds values (checked via console) in page.cshtml.cs:
var user = await _userManager.FindByIdAsync(id);
UserViewModel UserModel = new UserViewModel();
UserModel.UserName = user.UserName;
UserModel.Email = user.Email;
UserModel.Id = user.Id;
Console.WriteLine(UserModel.UserName);
Console.WriteLine(UserModel.Id);
Console.WriteLine(UserModel.Email);
If I try to access it on the corresponding page (page.cshtml) I can only access its name without any problems:
#Html.DisplayNameFor(model => model.umodel.Email)
When I want to access its content there is no value on the page.
#Html.DisplayFor(model => model.umodel.Email)
How can I access the values in this model on a razor page? All the solutions I found based on some kind of iterator and therefore models that had some kind of enumerator or where instanced and filled as a list.
From the code you posted, you aren't populating the page's UserViewModel property. You instantiated a different UserViewModel instance. You wrote the values of that to the Console, but the actual model property (umodel) has not been populated.
Try this in the OnGet method:
var user = await _userManager.FindByIdAsync(id);
umodel.UserName = user.UserName;
umodel.Email = user.Email;
umodel.Id = user.Id;
When rendering property values, you don't need the DisplayFor helper (unless you are using display templates). You just need to prefix the property with #:
#Model.umodel.UserName
I figured it out. There hast to be an instance of the model / class but in a specific way and naming. See following example:
Model:
public class IdentityUserModel
{
public string Id { get; set; }
public string ?UserName { get; set; }
public string ?Email { get; set; }
}
Reference to model in the Main class of the Page (page.cshtml.cs):
public IdentityUserModel IUserModel { get; set; }
Then the important part in the OnGet/OnGetAsync function(?) (page.cshtml.cs):
IUserModel = new(); // <-- instance
var user = [whatever...]
IUserModel.UserName = user.UserName;
IUserModel.Email = user.Email;
IUserModel.Id = user.Id;
Then to write on the page.cshtml:
#Model.IUserModel.Id
My understanding is that there has to be an instance of the class in die page context with exactly the same name (therefore = new() without instance name). I may have been blind but reading throug microsofts learn pages again this is was not clear at all to me.
Thanks to Mike Brind for sending me in the right direction with his input.
I have a view-model like this:
public class U1MyProfile1ViewModel : U1Profile
{
public List<SelectListItem> CountryList { get; set; }
}
Thinking that I want the model accessible to the view, plus a some extra fields that aren't really part of the model, such as a drop down list of countries.
Then in the controller I try to "pass the model over to the view-model"
var myProfile = await _mainDbContext.U1Profiles
.AsNoTracking()
.FirstOrDefaultAsync(i => i.SiteUserId == mySiteUserId);
U1MyProfile1ViewModel myProfileViewModel = (U1MyProfile1ViewModel)myProfile;
this compiles, but I get a runtime error of:
InvalidCastException: Unable to cast object of type 'WebApp.Models.U1Profile' to type 'WebApp.ViewModels.U1MyProfile1ViewModel'.
Any ideas on how to do this easily?
Something simpler than assigning the model to the view-model field by field.
Set your View model like follow:
View modal
public class U1MyProfile1ViewModel
{
public List<SelectListItem> CountryList { get; set; }
public U1Profile U1Profile{get;set;}
public string othervariable{get;set;}
}
Controller
var myProfile = await _mainDbContext.U1Profiles
.AsNoTracking()
.FirstOrDefaultAsync(i => i.SiteUserId == mySiteUserId);
U1MyProfile1ViewModel myProfileViewModel = new U1MyProfile1ViewModel;
U1MyProfile1ViewModel.U1Profile=myProfile;
U1MyProfile1ViewModel.CountryList=yourcountrylist;
And finally just passed your viewmodal to View and you get your result.
For better understanding just see below link:
Link1
Link2
I want to assign my url parameters to Model properties, passed as a parameter to the associated Action. For example;
Say, my url is http://www.example.com/Item/Index?color=red&size=50
My action inside the controller is like below:
public class ItemController : Controller
{
public ActionResult Index(MyModel myModel)
{
//
return View(myModel);
}
}
I want to configure the model or whatever necessary so that my model takes the color and size as field values. The following didn't work:
public class MyModel
{
[Display(Name = "color")]
public string Color{ get; set; }
[Display(Name = "size")]
public string Size{ get; set; }
}
What would be the correct way to solve the problem?
Thanks for any suggestion.
Update
Well, yes! The code above would work correctly, because Url parameter names are the same as model property names. I should explain my problem exactly as I encounter for the next time, sorry.
I must correct a part of my question to make it clear. The url should have been: http://www.example.com/Item/Index?c=red&s=50 to detect the problem.
If the url is like that, the code would not work. Because Url parameters don't have the same name as Model properties.
Updated model is below:
public class MyModel
{
[Display(Name = "c")]
public string Color{ get; set; }
[Display(Name = "s")]
public string Size{ get; set; }
}
Try adding [FromUri] in front of the parameter.
public class ItemController : Controller
{
public ActionResult Index([FromUri] MyModel myModel)
{
// do something
return View();
}
}
debugging the issue
Here are some suggestions in debugging the issue, as it should work out of the box.
try binding to primitive types
public class ItemController : Controller
{
public ActionResult Index(string color, string size)
{
// do something
return View();
}
}
Try reading out of the request object directly
var size = this.Request["size"];
If either of those work there is an issue with your model binding.
Update
If you want to have the query string parameters different to the model in MVC you'll need to have a custom model binder. Take a look at Asp.Net MVC 2 - Bind a model's property to a different named value and http://ole.michelsen.dk/blog/bind-a-model-property-to-a-different-named-query-string-field.html which extends the answer a little.
https://github.com/yusufuzun/so-view-model-bind-20869735 has an example with some html helpers that could be useful.
Model:
public partial class TBLAppUser
{
public bool isActive { get; set; }
}
View:
#Html.CheckBoxFor(u => u.useredit.isActive)
you initialize an instance of TBLAppUser, set the IsActive of that instance to true, and pass that instance to the view. This is quite a simple situation. I think you better look at introductory tutorials found in here asp.net/mvc/overview/getting-started .
following is how your controller action would look like
[HttpGet]
public ActionResult Index()
{
var mainModel = //what ever the model you represent by u in the view
mainModel.useredit = new TBLAppUser{ isActive = true};
return View(mainModel);
}
ASP.NET MVC (or rather Html.Helpers and base page implementation) assumes that there will be one type for both rendering and posting (namely Model).
This is a violation of ISP, isn't it?
I am tempted to derive my Edit views (those that have different render-data, and post-data) from a custom EditPageBaseView<TViewModel, TFormData>.
The problem is I want my validation and post work against FormData instance (stored inside ViewModel), but MVC assumes that entire ViewModel will be POSTed back.
Is there an OOB way to facilitate that? (I didn't find one if there is).
Is it a bad idea (in concept) to have separate data types for different operations exposed by a service (a view in this case).
I tend to follow the CQRS model when constructing my view models. All rendering is done with ViewModel classes and all posting back is done with Command classes. Here's a contrived example. Let's say we have a View with a small form for creating users.
The ViewModel and Command classes looks like this:
public abstract class ViewModel {}
public abstract class Command: ViewModel
public class CreateUserViewModel : ViewModel
{
public string Username { get; set; }
public string Password { get; set; }
public string PasswordConfirm { get; set; }
}
public class CreateUserCommand : Command
{
public string Username { get; set; }
public string Password { get; set; }
public string PasswordConfirm { get; set; }
}
The UserController creates a CreateUserViewModel as the model for the Get request and expects a CreateUserCommand for the Post request:
public ActionResult CreateUser()
{
// this should be created by a factory of some sort that is injected in
var model = new CreateUserViewModel();
return View(model);
}
[HttpPost]
public ActionResult CreateUser(CreateUserCommand command)
{
// validate and then save the user, create new CreateUserViewModel and re-display the view if validation fails
}
Model binding takes care of ensuring that the properties of the Posted CreateUserCommand are populated properly, even though the Get View is bound to a CreateUserViewModel.
They don't have to match, but they do match by default.
If you don't want them to match, you can specify a different model in your Form or ActionLink:
Example of a Mismatch using Razor and C#:
Index.chtml:
#model FirstModel
<div>
#using (Html.BeginForm("Action", "ControllerName", new { ParameterName = new SecondModel { First = "First", Second = "Second" } }, FormMethod.Post)) {
<input type="submit" value="Submit Button" />
}
</div>
The Controller:
public class ControllerName : Controller {
public ActionResult Index() {
return View(new FirstModel());
}
public ActionResult Action(SecondModel ParameterName) {
return View() // Where to now?
}