So I am new to ASP.NET MVC and I would like to create a view with a text box for each item in a collection. How do I do this, and how do I capture the information when it POSTs back? I have used forms and form elements to build static forms for a model, but never dynamically generated form elements based on a variable size collection.
I want to do something like this in mvc 3:
#foreach (Guest guest in Model.Guests)
{
<div>
First Name:<br />
#Html.TextBoxFor(???) #* I can't do x => x.FirstName here because
the model is of custom type Invite, and the
lambda wants to expose properties for that
type, and not the Guest in the foreach loop. *#
</div>
}
How do I do a text box for each guest? And how do I capture them in the action method that it posts back to?
Thanks for any help.
Definitely a job for an editor template. So in your view you put this single line:
#Html.EditorFor(x => x.Guests)
and inside the corresponding editor template (~/Views/Shared/EditorTemplates/Guest.cshtml)
#model AppName.Models.Guest
<div>
First Name:<br />
#Html.TextBoxFor(x => x.FirstName)
</div>
And that's about all.
Now the following actions will work out of the box:
public ActionResult Index(int id)
{
SomeViewModel model = ...
return View(model);
}
[HttpPost]
public ActionResult Index(SomeViewModel model)
{
if (!ModelState.IsValid)
{
return View(model);
}
// TODO: do something with the model your got from the view
return RedirectToAction("Success");
}
Note that the name of the editor template is important. If the property in your view model is:
public IEnumerable<Guest> Guests { get; set; }
the editor template should be called Guest.cshtml. It will automatically be invoked for each element of the Guests collection and it will take care of properly generating ids and names of your inputs so that when you POST back everything works automatically.
Conclusion: everytime you write a loop (for or foreach) inside an ASP.NET MVC view you should know that you are doing it wrong and that there is a better way.
You can do this:
#for (int i = 0; i < Model.Guests.Count; i++) {
#Html.TextBoxFor(m => m.Guests.ToList()[i].FirstName)
}
There are more examples and details on this post by Haacked.
UPDATE: The controller post action should look like this:
[HttpPost]
public ActionResult Index(Room room)
{
return View();
}
In this example I'm considering that you have a Room class like this:
public class Room
{
public List<Guest> Guests { get; set; }
}
That's all, on the post action, you should have the Guests list correctly populated.
Related
I have a view model that is used to display a form on one view, and then is also used to represent the POST data to an action. The action then displays another view model that contains much of the same data from the first view model. However, the first view model has several "display only" properties that are also required on the second view model (for display only on the second view also).
I am wondering what the best way to pass this "display only" data to the second view would be. Currently, the best solution I have come up with is to have a bunch of hidden form fields that contain the display only property values, and then the model gets auto-populated for the action that handles the form POST. However, using hidden form fields seems very "hackish", and there seems like there should be a better solution to passing this data to another view The action doesn't need the display only information, it is only accessing it to populate the properties of the second view model that is passed to the second view.
Let me just explain my question with code, as what I am after is probably better understood through code than words.
Models:
public class SearchFilters
{
// ...
}
public class SearchResult
{
public int Id { get; set; }
public bool Selected { get; set; }
public string SomeDisplayValue1 { get; set; }
public string SomeDisplayValue2 { get; set; }
// ...
}
public class ResultsViewModel
{
public IList<SearchResult> Results { get; set; }
// ...
}
public class DoSomethingWithSelectedResultsViewModel
{
public IList<SearchResult> SelectedResults { get; set; }
public string SomeOtherProperty { get; set; }
// ...
}
Controller:
[HttpPost]
public ActionResult Results(SearchFilters filters)
{
ResultsViewModel results = new ResultsViewModel();
// ...
return new View(results);
}
[HttpPost]
public ActionResult DoSomethingWithSelectedResults(ResultsViewModel model)
{
// ...
return View(new DoSomethingWithSelectedResultsViewModel
{
SelectedResults = model.Results.Where(r => r.Selected).ToList(),
SomeOtherProperty = "...",
// ...
});
}
View: Results.cshtml
#model ResultsViewModel
#using (Html.BeginForm("DoSomethingWithSelectedResults", "Search"))
{
<table>
for (int i = 0; i < Model.Results.Count; i++)
{
<tr>
<td>
#Html.CheckBoxFor(m => Model.Results[i].Selected)
#* I would like to eliminate these hidden inputs *#
#Html.HiddenFor(m => Model.Results[i].Id)
#Html.HiddenFor(m => Model.Results[i].SomeDisplayValue1)
#Html.HiddenFor(m => Model.Results[i].SomeDisplayValue2)
</td>
<td>#Html.DisplayFor(m => Model.Results[i].SomeDisplayValue1)</td>
<td>#Html.DisplayFor(m => Model.Results[i].SomeDisplayValue2)</td>
<tr>
}
</table>
<button type="submit">Do Something With Selected Results</button>
}
As far as I know, one of the best way to pass data from View to another View through a Controller is to use ViewBag, ViewData or TempData. As an example, you can pass the data retrieved from View I as shown below:
TempData[DataToBePassed] = model.CustomData;
And then retrieve this data in View II similar to that:
#if(TempData[DataToBePassed] != null)
{
var dataFromFirstView = TempData[DataToBePassed];
}
For more information take a look at When to use ViewBag, ViewData, or TempData in ASP.NET MVC 3 applications.
You could put the model in the TempData property of the controller, that way it's automatically available in the next request.
More here
Found what I was looking for, I just hadn't worked with MVC enough yet to know about it. The Controller.UpdateModel method does exactly what I was looking for.
Example (using the code from the question):
[HttpPost]
public ActionResult DoSomethingWithSelectedResults()
{
// Load initial model data here, in this case I had simply cached the results in
// temp data in the previous action as suggested by Emeka Awagu.
ResultsViewModel model = (ResultsViewModel)TempData["results"];
// Call UpdateModel and let it do it's magic.
UpdateModel(model);
// ...
return View(new DoSomethingWithSelectedResultsViewModel
{
SelectedResults = model.Results.Where(r => r.Selected).ToList(),
SomeOtherProperty = "...",
// ...
});
}
Using this method I was able to eliminate all the hidden form fields and did not have to write any custom copy logic, since UpdateModel deals with it automatically.
Note: I did have to implement some custom model binders to get things to work correctly with dictionaries and collections (see here, here, and here).
I am making WCF service call using MyViewRequest view fields inside HttpPost ActionHandler. The goal is to show response using partial view, MyViewResponse
In brief I need to achieve these two items-
Disable load of partial view on first load.
Display Response (along with Request) after service call.
MyViewRequest.cshtml
#using (Html.BeginForm())
{
#Html.ValidationSummary(false)
//html code
}
</div>
<div id="dvResponse">
#Html.Partial("MyViewResponse");
</div>
Partial view: MyViewResponse.cshtml
#model MvcApplication3.Models.MyModel
#{
ViewBag.Title = "MyViewResponse";
}
<h2>MyView</h2>
#Html.Label(Model.MyName, "My Name")
This was pretty straight forward in Asp.Net using userControl, But stuck up here, How can we achieve this in MVC3.
I think the best way is to transfer your data using ViewModels. Let's assume you want to have an app something like stackoverflow where you have a question and user can post an answer and it will be shown after the post along with the question.
public class PostViewModel
{
public int ID { set;get;}
public string Text { set;get;}
public List<PostViewModel> Answers { set;get;}
public string NewAnswer { set;get;}
}
in your GET action, you show the question. Get the id from the url and get the Question details from your service/repositary.
public ActionResult Show(int id)
{
var post=new PostViewModel();
post=yourService.GetQuestionFromID(id);
post.Answers=yourService.GetAnswersFromQuestionID(id);
return View(post);
}
Assuming yourService.GetQuestionFromID method returns an object of PostViewModel with the propety values filled. The data can be fetched from your database or via a WCF service call. It is up to you. Also yourService.GetAnswersFromQuestionID method returns a list of PostViewModel to represent the Answers for that question. You may put both these into a single method called GetQuestionWithAnswers. I wrote 2 methods to make it more clear.
Now in your Show view
#model PostViewModel
#Html.LabelFor(x=>x.Text);
#using(Html.Beginform())
{
#Html.HiddenFor(x=>x.ID);
#Html.TextBoxFor(x=>x.NewAnswer)
<input type="submit" />
}
<h3>Answers</h3>
#if(Model.Answers!=null)
{
#Html.Partial("Responses",Model.Answers)
}
And your Partial view will be strongly typed to a collection of PostViewModel
#model List<PostViewModel>
#foreach(var item in Model)
{
<div> #item.Text </div>
}
Handling the postback is simple (HttpPost)
[HttpPost]
public ActionResult Show(PostViewModel model)
{
if(ModelState.IsValid)
{
//get your data from model.NewAnswer property and save to your data base
//or call WCF method to save it.
//After saving, Let's redirect to the GET action (PRG pattern)
return RedirectToAction("Show",new { #id=model.ID});
}
}
I am new to Asp.net MVC and have no idea as to how can i perform the search. Here's my requirement, please tell me how will you handle this :-
I need to have textbox where user can enter a search query or string. The user then clicks on a button or presses enter to submit it. The string needs to matched with a table's property name.
NOTE:- Querying the data and fetching the result isn't the main point here. All I need to know is how will you take the user input and pass it to a controller action or whatever for further processing. Just tell me how will you read the user input and where will you send it to search.
Asp.Net MVC uses standard HTTP verbs. For the html part, it's a normal html form that points to an url. Server side, that url will be routed to a controller/action which will handle the input and do what is needed.
Let's have a sample. You want to make a search form. First of all, it's a best practice to have search forms use the HTTP GET method instead of POST, so the search results can be bookmarked, linked, indexed, etc. I won't be using Html.BeginForm helper method to make things more clear.
<form method="get" action="#Url.Action("MyAction", "MyController")">
<label for="search">Search</label>
<input type="text" name="search" id="search" />
<button type="submit">Perform search</button>
</form>
That's all the html you need. Now you'll have a controller called "MyController" and the method will be something like this:
[HttpGet]
public ActionResult MyAction(string search)
{
//do whatever you need with the parameter,
//like using it as parameter in Linq to Entities or Linq to Sql, etc.
//Suppose your search result will be put in variable "result".
ViewData.Model = result;
return View();
}
Now the view called "MyAction" will be rendered, and the Model of that view will be your "result". Then you'll display it as you wish.
As always in an ASP.NET MVC application you start by defining a view model which will express the structure and requirements of your view. So far you have talked about a form containing a search input:
public class SearchViewModel
{
[DisplayName("search query *")]
[Required]
public string Query { get; set; }
}
then you write a controller:
public class HomeController : Controller
{
public ActionResult Index()
{
return View(new SearchViewModel());
}
[HttpPost]
public ActionResult Index(SearchViewModel model)
{
if (!ModelState.IsValid)
{
// There was a validation error => redisplay the view so
// that the user can fix it
return View(model);
}
// At this stage we know that the model is valid. The model.Query
// property will contain whatever value the user entered in the input
// So here you could search your datastore and return the results
// You haven't explained under what form you need the results so
// depending on that you could add other property to the view model
// which will store those results and populate it here
return View(model);
}
}
and finally a view:
#model SearchViewModel
#using (Html.BeginForm())
{
#Html.LabelFor(x => x.Query)
#Html.EditorFor(x => x.Query)
#Html.ValidationMessageFor(x => x.Query)
<button type="submit">Search</button>
}
This is the best way to do it.
Create a ViewModel
public class SearchViewModel
{
public string Query { get; set; }
}
Create a Controller
public class SearchController : Controller
{
[HttpPost]
public ActionResult Search(SearchViewModel model)
{
// perform search based on model.Query
// return a View with your Data.
}
}
Create the View
// in your view
#using (Html.BeginForm("Search", "SearchController"))
{
#Html.TextBox("Query")
<input type="submit" value="search" />
}
hope this helps
I'm making an invite system where a user when registering to the site can specify a user who refereed them.
There's also a way for existing users to send invites. The friend would recieve a link:
http://www.foo.com/account/register?referal=sandyUser216
How can I get that value sandyUser216 and place it as the value inside of a text input box?
I'm using C# and MVC3.
Check the Request.QueryString.
<input type="text" value="#Request.QueryString["referal"]" />
Or put it in a Model property rather than having it in the view.
As always in an ASP.NET MVC application you start by writing a view model that will represent the information contained in your view:
public class RegisterViewModel
{
[Required]
public string Referal { get; set; }
}
then you write controller actions for respectively showing the registration form and processing it:
public ActionResult Register(RegisterViewModel model)
{
return View(model);
}
[HttpPost]
[ActionName("Register")]
public ActionResult ProcessRegistration(RegisterViewModel model)
{
if (!ModelState.IsValid)
{
return View(model);
}
// TODO: perform the registration
return RedirectToAction("success");
}
and finally you write the corresponding strongly typed view:
#model RegisterViewModel
#using (Html.BeginForm())
{
#Html.LabelFor(x => x.Referal)
#Html.EditorFor(x => x.Referal)
#Html.ValidationMessageFor(x => x.Referal)
<button type="submit">Register</button>
}
Now all that's left is to simply navigate to /account/register?referal=sandyUser216.
And you have accomplished the whole MVC pattern. Should you skip any of those 3 letters it means that you are doing ASP.NET MVC incorrectly.
I have a List of about 20 items I want to display to the user with a checkbox beside each one (a Available property on my ViewModel).
When the form is submitted, I want to be able to pass the value of each checkbox that is checked back to my controller method via the Selections property on my ViewModel.
How would I go about doing this using the Form Helper class in MVC? Is this even possible?
PS: I don't want a listbox where the user can just highlight multiple items.
Model:
public class MyViewModel
{
public int Id { get; set; }
public bool Available { get; set; }
}
Controller:
public class HomeController: Controller
{
public ActionResult Index()
{
var model = Enumerable.Range(1, 20).Select(x => new MyViewModel
{
Id = x
});
return View(model);
}
[HttpPost]
public ActionResult Index(IEnumerable<MyViewModel> model)
{
...
}
}
View ~/Views/Home/Index.cshtml:
#model IEnumerable<AppName.Models.MyViewModel>
#using (Html.BeginForm())
{
#Html.EditorForModel()
<input type="submit" value="OK" />
}
Editor template ~/Views/Home/EditorTemplates/MyViewModel.cshtml:
#model AppName.Models.MyViewModel
#Html.HiddenFor(x => x.Id)
#Html.CheckBoxFor(x => x.Available)
The best thing to do would be to create a template that can be reused. I have some code at home that I can post later tonight.
Maybe check SO for similar posts in the mean time.
Dynamic list of checkboxes and model binding
This blog post also could help;
http://tugberkugurlu.com/archive/how-to-handle-multiple-checkboxes-from-controller-in-asp-net-mvc-sample-app-with-new-stuff-after-mvc-3-tools-update