c# - Asp:net MVC 3: @Html.EditorFor a subcollection of my model in a template?

Question

I've been stuck a long time to edit a subcollection of my model, the collection of the model was coming null.

I finally found a solution, but I find it a little dirty:

First my tests datas:

Model object:

    public class ContainerObject
    {
        public String Title { get; set; }
        public List<ContainedObject> ObjectList { get; set; }
    }

Sub collection object:

public class ContainedObject
{
    public int Id { get; set; }
    public String Text { get; set; }
    public Boolean IsSelected { get; set; }
}

Controller method which generate the object

    public ActionResult TestForm()
    {
        return View(new ContainerObject()
        {
            Title = "This is a sample title",
            ObjectList = new List<ContainedObject>()
                {
                    new ContainedObject(){Id=1, IsSelected = true, Text="ObjectOne"},
                    new ContainedObject(){Id=2, IsSelected = false, Text="ObjectTwo"},
                    new ContainedObject(){Id=3, IsSelected = true, Text="ObjectThree"},
                    new ContainedObject(){Id=4, IsSelected = false, Text="ObjectFour"},
                }
        });
    }

Controller which receive the edited object

    [HttpPost]
    public ActionResult TestFormResult(ContainerObject filledObject)
    {
        return View();
    }

The view

@model WebTestApplication.Models.ContainerObject

@{
    ViewBag.Title = "TestForm";
}
@using (Html.BeginForm("TestFormResult","Home", FormMethod.Post)){
    @Html.EditorFor(x => x.Title)
    Html.RenderPartial("ContainedObject", Model.ObjectList);
    <input type="submit"  value="Submit"/>
}

The partial view(ContainedObject.cshtml)

@model IEnumerable<WebTestApplication.Models.ContainedObject>
@{
    ViewBag.Title = "ContainedObject";
    int i = 0;
}
@foreach (WebTestApplication.Models.ContainedObject currentObject in Model)
{ 
    <br />
    @Html.Label(currentObject.Text);
    @Html.CheckBox("ObjectList[" + i + "].IsSelected", currentObject.IsSelected);                                                                                                     
    @Html.Hidden("ObjectList[" + i + "].Id", currentObject.Id);                                                                                                
    @Html.Hidden("ObjectList[" + i + "].Text", currentObject.Text);
    i++;
}

This is actually working, but I've one problem:

• I've to generate names myself and specify the property of the container object

I tried to use Html.EditorFor instead of Html.RenderPartial in the view, the problem is that it generate me the name "ObjectList.[0].Id"(with a additional . between the property name and the accessor).

I also tried to use only @Html.EditorFor in the partial view, but it create vars with the name of the object.

If I don't use any template, it works:

    @model WebTestApplication.Models.ContainerObject

@{
    ViewBag.Title = "TestForm";
}
@using (Html.BeginForm("TestFormResult", "Home", FormMethod.Post))
{
    @Html.EditorFor(x => x.Title)
    for (int i = 0; i < Model.ObjectList.Count; i++)
    {
        <br />
        @Html.Label(Model.ObjectList[i].Text);
        @Html.CheckBoxFor(m => Model.ObjectList[i].IsSelected);
        @Html.HiddenFor(m => Model.ObjectList[i].Id);
        @Html.HiddenFor(m => Model.ObjectList[i].Text);
    }

    <br /><input type="submit"  value="Submit"/>
}

But here it's a simple template, but in my real case, I will have much more data, and this will be re-used multiple time. So what is my best option?

Answer 1

You can simplify your code by introducing the EditorTemplate. Here is how:

• The main view remains pretty much the same except we replaced RenderPartial with EditorFor:

TestForm.cshtml

@model WebTestApplication.Models.ContainerObject

@{
    ViewBag.Title = "TestForm";
    Layout = "~/Views/Shared/_Layout.cshtml";
}

@using (Html.BeginForm("TestFormResult", "Home", FormMethod.Post)) {
    @Html.EditorFor(m => m.Title)
    @Html.EditorFor(m => m.ObjectList);

    <input type="submit" value="Submit" />
}

• Then create a folder named EditorTemplates under Views/Home (assuming your controller is Home):

• and add the following template for the ContainedObject:

ContainedObject.cshtml

@model WebTestApplication.Models.ContainedObject

<p>
    @Html.DisplayFor(m => m.Text)
    @Html.CheckBoxFor(m => m.IsSelected)
    @Html.HiddenFor(m => m.Id)
    @Html.HiddenFor(m => m.Text)
</p>

The editor will automatically iterate through the list of objects rendering the view for each of them. Hope it helps.