Using the EditorFor templates is a really nice feature of ASP.Net MVC 3, but is it possible to get EditorFor to render an unpopulated template to allow for creation of records?
Or is there some other way to do this?
The ways in which I am trying to do this is as follows:
#Html.EditorFor(model => model)
#Html.EditorFor(x => new List<Business.ViewModel.Affiliate.Contact>())
#Html.EditorFor(new List<Business.ViewModel.Affiliate.Contact>())
#Html.EditorFor(new Business.ViewModel.Affiliate.Contact())
The first one obviously works, however the subsequent ones (which demonstrate what I am trying to do) all fail with the following error:
Templates can be used only with field access, property access, single-dimension array index, or single-parameter custom indexer expressions.
The model in question is:
IEnumerable<Business.ViewModel.Affiliate.Contact>
It's the responsibility of the controller to prepare the view model that will be passed to the view. So if you need for example to initialize your view view model with 5 empty contact rows you could do this simply in your controller:
public ActionResult Index()
{
var model = new MyViewModel
{
// Add 5 empty contacts
Contacts = Enumerable.Range(1, 5).Select(x => new Contact()).ToList()
};
return View(model);
}
and in your view use the EditorFor helper as usual:
#model MyViewModel
...
#Html.EditorFor(x => x.Contacts)
This will render the corresponding editor template for each of the 5 elements we have added to the Contacts collection.
If your question doesn't involve AJAX, then I would design the ViewModel as following:
class MyList
{
public List<MyRow> Rows {get;set;}
public MyRow NewRow {get;set;}
}
Then you can easily add a blank editor bound to NewRow property. And in the controller you add the NewRow to Rows on subsequent calls.
Related
It has been intriguing that my MVC3 razor form renders duplicated values inside a foreach code block in spite of correctly receiving the data from the server. Here is my simple form in MVC3 Razor...
-- sample of my .cshtml page
#model List<Category>
#using (#Html.BeginForm("Save", "Categories", FormMethod.Post))
{
foreach (Category cat in Model)
{
<span>Test: #cat.CategoryName</span>
<span>Actual: #Html.TextBoxFor(model => cat.CategoryName)</span>
#Html.HiddenFor(model => cat.ID)
<p>---</p>
}
<input type="submit" value="Save" name="btnSaveCategory" id="btnSaveCategory" />
}
My controller action looks something like this -
[HttpPost]
public ActionResult Save(ViewModel.CategoryForm cat)
{
... save the data based on posted "cat" values (I correctly receive them here)
List<Category> cL = ... populate category list here
return View(cL);
}
The save action above returns the model with correct data.
After submitting the form above, I expect to see values for categories similar to the following upon completing the action...
Test: Category1, Actual:Category1
Test: Category2, Actual:Category2
Test: Category3, Actual:Category3
Test: Category4, Actual:Category4
However #Html.TextBoxFor duplicates the first value from the list. After posting the form, I see the response something like below. The "Actual" values are repeated even though I get the correct data from the server.
Test: Category1, Actual:Category1
Test: Category2, Actual:Category1
Test: Category3, Actual:Category1
Test: Category4, Actual:Category1
What am I doing wrong? Any help will be appreciated.
The helper methods like TextBoxFor are meant to be used with a ViewModel that represent the single object, not a collection of objects.
A normal use would be:
#Html.TextBoxFor(c => c.Name)
Where c gets mapped, inside the method, to ViewData.Model.
You are doing something different:
#Html.TextBoxFor(c => iterationItem.Name)
The method internall will still try to use the ViewData.Model as base object for the rendering, but you intend to use it on the iteration item. That syntax, while valid for the compiler, nets you this problem.
A workaround is to make a partial view that operates on a single item: inside that view you can use html helpers with correct syntax (first sample), and then call it inside the foreach, passing the iteration item as parameter. That should work correctly.
A better way to do this would be to use EditorTemplates.
In your form you would do this:
#model List<Category>
#using (#Html.BeginForm("Save", "Categories", FormMethod.Post))
{
#Html.EditorForModel()
<input type="submit" value="Save" name="btnSaveCategory" id="btnSaveCategory" />
}
Then, you would create a folder called EditorTemplates, either in the ~/Views/Shared folder or in your Controllers View folder (depending on whether you want to share the template with the whole app or just this controller), and in the EditorTemplates folder, create a Category.cshtml file which looks like this:
#model Category
<span>Test: #Model.CategoryName</span>
<span>Actual: #Html.TextBoxFor(model => model.CategoryName)</span>
#Html.HiddenFor(model => model.ID)
<p>---</p>
MVC will automatically iterate over the collection and call your template for each item in it.
I've noticed that using foreach loops within Views causes the name attributes of text boxes to be rendered the same for every item in the collection. For your example, every text box will be rendered with the following ID and Name attributes:
<input id="cat_CategoryName" name="cat.CategoryName" value="Category1" type="text">
When your controller receives the form data collection, it won't be able reconstruct the collection as different values.
The solution
A good pattern I've adopted is to bind your View to the same class you want to post back. In the example, model is being bound to List<Category> but the controller Save method receives a model ViewModel.CategoryForm. I would make them both the same.
Use a for loop instead of a foreach. The name/id attributes will be unique and the model binder will be able to distinguish the values.
My final code:
View
#model CategoryForm
#using TestMvc3.Models
#using (#Html.BeginForm("Save", "Categories", FormMethod.Post))
{
for (int i = 0; i < Model.Categories.Count; i++)
{
<span>Test: #Model.Categories[i].CategoryName</span>
<span>Actual: #Html.TextBoxFor(model => Model.Categories[i].CategoryName)</span>
#Html.HiddenFor(model => Model.Categories[i].ID)
<p>---</p>
}
<input type="submit" value="Save" name="btnSaveCategory" id="btnSaveCategory" />
}
Controller
public ActionResult Index()
{
// create the view model with some test data
CategoryForm form = new CategoryForm()
{
Categories = new List<Category>()
};
form.Categories.Add(new Category() { ID = 1, CategoryName = "Category1" });
form.Categories.Add(new Category() { ID = 2, CategoryName = "Category2" });
form.Categories.Add(new Category() { ID = 3, CategoryName = "Category3" });
form.Categories.Add(new Category() { ID = 4, CategoryName = "Category4" });
// pass the CategoryForm view model
return View(form);
}
[HttpPost]
public ActionResult Save(CategoryForm cat)
{
// the view model will now have the correct categories
List<Category> cl = new List<Category>(cat.Categories);
return View("Index", cat);
}
I'm experimenting with ASP.NET MVC3 and want to simply populate a dropdown list with data I get from a LINQ2SQL class, like so
controller (I know, Linq doesn't belong in the controller)
var allUsers = (from u in _userDataContext.Users
select u).ToList();
ViewBag.allUsers = allUsers.ToList();
return View();
view:
<select id="drop_heroes">
#foreach (var u in ViewBag.allUsers)
{
<option value="#u.pk_userid">#u.email</option>
}
</select>
That works fine, but I would like to use Razor #Html.Dropdownlist to create the same dropdown list, but can't find any info to make this work with Linq data.
I know, Linq doesn't belong in the controller
Then why are you using it in a controller? Anyway, at least it's fine that you know it.
Here's an example. As always in an ASP.NET MVC application you start by defining a view model which will represent the data that you need in the view. So in your case you need to display a dropdown so you define a list of users and a selected user id:
public class MyViewModel
{
public string SelectedUserId { get; set; }
public IEnumerable<SelectListItem> Users { get; set; }
}
then you define a controller action which will populate this view model from your repository and handle it to the view:
public ActionResult Index()
{
var model = new MyViewModel
{
Users = _userDataContext.Users.ToList().Select(x => new SelectListItem
{
Value = x.pk_userid.ToString(),
Text = x.email
})
}
return View(model);
}
and finally you will have a view which will be strongly typed to your view model and use HTML helpers to generate the dropdownlist:
#model MyViewModel
#using (Html.BeginForm())
{
#Html.DropDownListFor(x => x.SelectedUserId, Model.Users)
<button type="submit">OK</button>
}
Things to notice:
Usage of view models
Usage of a strongly typed view
Usage of strongly typed HTML helpers to generate markup such as form elements and input fields
Getting rid of weakly typed structures such as ViewBag
If you follow these simple rules you will see how much easier your life as an ASP.NET MVC developer will become.
I'm using Entity Framework Code First to generated my database, so I have an object defined like the following:
public class Band
{
public int Id { get; set; }
[Required(ErrorMessage = "You must enter a name of this band.")]
public string Name { get; set; }
// ...
public virtual ICollection<Genre> Genres { get; set; }
}
Now I'm looking at a create view for this and the default scaffolding isn't adding Genres to my form, which from past experience is about what I expect.
Looking online I've found Using ASP.NET MVC v2 EditorFor and DisplayFor with IEnumerable<T> Generic types which seems to come closest to what I want, but doesn't seem to make sense with Razor and possibly MVC 3, per ASP.NET MVC 3 Custom Display Template With UIHint - For Loop Required?.
At present I've added the listing of genres to the ViewBag and then loop through that listing in my create view:
#{
List<Genre> genreList = ViewBag.Genres as List<Genre>;
}
// ...
<ul>
#for (int i = 0; i < genreList.Count; i++)
{
<li><input type="checkbox" name="Genres" id="Genre#(i.ToString())" value="#genreList[i].Name" /> #Html.Label("Genre" + i.ToString(), genreList[i].Name)</li>
}
</ul>
Outside of not yet handling cases where the user has JavaScript disabled and the checkboxes need to be re-checked, and actually updating the database with this information, it does output the genres as I'd like.
But this doesn't feel right, based on how good MVC 3 has become.
So what's the most effective way to handle this in MVC 3?
I don't send lists into my View via the ViewBag, instead I use my viewmodel to do this. For instance, I did something like this:
I have an EditorTemplate like this:
#model IceCream.ViewModels.Toppings.ToppingsViewModel
<div>
#Html.HiddenFor(x => x.Id)
#Html.TextBoxFor(x =x> x.Name, new { #readonly="readonly"})
#Html.CheckBoxFor(x => x.IsChecked)
</div>
which I put in my Views\IceCream\EditorTemplates folder. I use this to display some html for allowing the user to "check" any particular topping.
Then in my View I've got something like this:
#HtmlEditorFor(model => model.Toppings)
and that will use that result in my EditorTemplate being used for each of the toppings in the Toppings property of my viewmodel.
And then I've got a viewmodel which, among other things, includes the Toppings collection:
public IEnumerable<ToppingsViewModel> Toppings { get; set; }
Over in my controller, among other things, I retrieve the toppings (however I do that in my case) and set my viewmodel's property to that collection of toppings. In the case of an Edit, where toppings may have been selected previously, I set the IsChecked member of the TopingsViewModel and it'll set the corresponding checkboxes to checked.
Doing it this way provided the correct model binding so that when the user checked a few toppings, the underlying items in the collection reflected those selections. Worked well for me, hope it's helpful for you.
Im creating an application that allows me to record recipes. Im trying to create a view that allows me to add the basics of a recipe e.g. recipe name,date of recipe, temp cooked at & ingredients used.
I am creating a view that contains some jquery to load a partial view clientside.
On post im having a few troubles trying to get the values from the partial view that has been loaded using jquery.
A cut down version of my main view looks like (I initially want 1 partial view loaded)
<div id="ingredients">
#{ Html.RenderPartial("_AddIngredient", new IngredientViewModel()); }
</div>
<script type="text/javascript">
$(document).ready(function () {
var dest = $("#ingredients");
$("#add-ingredient").click(function () {
loadPartial();
});
function loadPartial() {
$.get("/Recipe/AddIngredient", {}, function (data) { $('#ingredients').append(data); }, "html");
};
});
</script>
My partial view looks like
<div class="ingredient-name">
#Html.LabelFor(x => Model.IngredientModel.IngredientName)
#Html.TextBoxFor(x => Model.IngredientModel.IngredientName)
</div>
<div class="ingredient-measurementamount">
#Html.LabelFor(x => Model.MeasurementAmount)
#Html.TextBoxFor(x => Model.MeasurementAmount)
</div>
<div class="ingredient-measurementtype">
#Html.LabelFor(x => Model.MeasurementType)
#Html.TextBoxFor(x => Model.MeasurementType)
</div>
Controller Post
[HttpPost]
public ActionResult Create(RecipeViewModel vm,IEnumerable<string>IngredientName, IEnumerable<string> MeasurementAmount, IEnumerable<string> MeasurementType)
{
Finally my viewmodel looks like
public class IngredientViewModel
{
public RecipeModel RecipeModel { get; set; }
public IEnumerable<IngredientModel> Ingredients { get; set; }
}
My controller is pretty ugly......im using Inumerble to get the values for MeasurementAmount & MeasurementType (IngredientName always returns null), Ideally I thought on the httppost Ingredients would be populated with all of the on I would be able Ingredients populated
What do I need to do to get the values from my partial view into my controller?
Why don't you take a look at the MVC Controlstoolkit
I think they would do what you want.
Without getting in too much detail. Can you change the public ActionResult Create to use FormCollection instead of a view model? This will allow you to see what data is coming through if any. It would help if you could post it then.
Your view model gets populated by using Binding - if you haven't read about it, it might be a good idea to do that. Finally I would consider wrapping your lists or enums into a single view model.
Possible Problem
The problem could lay with the fact that the new Partial you just rendered isn't correctly binded with your ViewModel that you post later on.
If you inspect the elements with firebug then the elements in the Partial should be named/Id'ed something like this: Ingredients[x].Property1,Ingredients[x].Property2 etc.
In your situation when you add a partial they are probably just called Property1,Property2.
Possible Solution
Give your properties in your partial the correct name that corresponds with your List of Ingredients. Something like this:
#Html.TextBox("Ingredients[x].Property1","")
Of, after rendering your partial just change all the names en ID's with jquery to the correct value.
It happens because fields' names from partial view do not fit in default ModelBinder convention. You should analyze what names fields have in your partial view.
Also you should implement correct way of binding collections to MVC controller. You could find example in Phil's Haack post
Assuming RecipeViewModel is the model being supplied to the partial view, try just accepting that back in your POST controller like this:
[HttpPost]
public ActionResult Create(RecipeViewModel vm)
{
//
}
You should get the model populated with all the values supplied in the form.
If i have a ViewModel like this:
public class SignupViewModel
{
[Required]
[DisplayName("Email:")]
public string EmailAddress { get; set; }
}
And use EditorFor to render out the form fields:
#Html.EditorFor(model => model.EmailAddress )
It will render <input type="text">. Cool.
But in this particular scenario, i have already retrieved Email from a different source, and i wish to pre-fill the form with this data, and show a label instead of a textbox (as i don't want them to change their email - don't worry about why).
I know i can use [UIHint], but can i do that programatically from the controller?
E.g:
var model = new SignupViewModel();
model.EmailAddress = GetFromMysterySource(); // How do i set a UIHint?
What's the best way to approach this? Should i use a seperate ViewModel altogether, which could mean changing my View from being strongly-typed to being dynamic, or should i not use EditorFor, or should i use a custom editor template?
Suggestions/advise would be greatly appreciated.
You can't apply an attribute at runtime. My suggestion would be to build a bit of logic into your view to control how the view renders the data. You may need to augment your model to indicate to the view which display to choose.
#if (Model.EmailAddressIsFixed)
{
#Html.DisplayFor( m => m.EmailAddress )
#Html.HiddenFor( m => m.EmailAddress ) // only if you need it to post back
}
else
{
#Html.EditorFor( m => m.EmailAddress )
}
If you are doing this in more than one place, then a custom editor template doing the same thing would probably be in order.
#Html.EditorFor( m => m.EmailAddress,
"FixedAddressTemplate",
new { Fixed = Model.EmailAddressIsFixed } )