Question

I have a list that I would like to group and edit within a razor view.

If the POCO is:

public class FooBar {

public string GroupName {get;set;}
public string SomeValue {get;set;}

// etc.

}

And the model in the View:

@model IEnumerable<FooBar>

And the Post action is like this:

[HttpPost]
        public ActionResult FooBarPost(IEnumerable<FooBar> model)

Normally to edit a list I would use this syntax in my view:

@Html.EditorForModel()

Which works great, it creates lovely little inputs like:

<input id="[0].SomeValue" />

And the post back is perfect.

Now if I want to change my view to the much less awesome:

<fieldset>
                        <legend>Legendary</legend>
                        @foreach (var group in Model.GroupBy(x => x.GroupName))
                        {
                            <h3>@group.Key</h3>

                            @Html.EditorFor(x => group)
                        }
                    </fieldset>

Then when I post my list comes back as null?

I remember there being a trick to fixing this, I just can’t remember what it was?

Thanks.

Edit:

added [Bind(Prefix="group")] to my action which now brings back just one of the input values.

I noticed the HTML generated looks like this (all on same page):

Group 1:

<input id="group_0__SomeValue" name="group[0].SomeValues" type="hidden" value="bla">  
<input id="group_1__SomeValue" name="group[1].SomeValues" type="hidden" value="bla">

Next group:

<input id="group_0__SomeValue" name="group[0].SomeValues" type="hidden" value="bla">

Answer 1

Assuming your goal is to render an editor for each unique instance of GroupName, change your code to look like the following:

@model IEnumerable<PlayMvc.Models.FooBar>
<fieldset>
    <legend>Legendary</legend>
    @using(Html.BeginForm("Test","Home", FormMethod.Post)){
        var groups = Model.GroupBy(x => x.GroupName).Select(x => x.First()) .ToList();
        for (int i = 0; i < groups.Count(); i++ )
        {
            <h3>@groups[i].GroupName</h3>

            @Html.EditorFor(x => groups[i])
        }
        <input type="submit" />
    }
</fieldset>

On your controller side do something as this:

public ActionResult Test([Bind(Prefix="groups")]List<FooBar> model)

Sidenote

Don’t use foreach when trying to work with enumerables to render items in the view, otherwise they will not have an indexer in the name. @Html.EditorFor(x => groups[i]) and @Html.EditorFor(x => group) would render different name tag in HTML, so model binder wouldn’t recognize it as part of a collection that it should reconstruct as input for your action.