Question

I have a model that can have a variable amount of items in a List<T>

In my view I then have the following:

@using (Html.BeginForm())
{
    int count = Model.Data.Filters.Count;
    for(int i = 0; i < count; i++)
    {
        <div>

        @Html.TextBox("filtervalue" + i)
        @Html.DropDownList("filteroptions"+i,Model.Data.Filters[i].FilterOptions)


        </div>
    }
    @Html.Hidden("LinkID", Url.RequestContext.RouteData.Values["id"])
}

Is there a way in my controller so I can set up the POST action method to bind to a model with variable items in it?

Also how would I construct the model to cope with this?

Thanks

Answer 1

You coud use editor templates, it will be much easier:

@using (Html.BeginForm())
{
    @Html.EditorFor(x => x.Data.Filters)
    @Html.Hidden("LinkID", Url.RequestContext.RouteData.Values["id"])
}

and inside the editor template (~/View/Shared/EditorTemplates/FilterModel.cshtml) which will be automatically rendered for each element of the Model.Data.Filters collection:

@model FilterModel
<div>
    @Html.TextBoxFor(x => x.FilterValue)
    @Html.DropDownListFor(x => x.SelectedFilterOption, Model.FilterOptions)
</div>

Now your POST controller action will simply look like this:

[HttpPost]
public ActionResult Foo(SomeViewModel model)
{
    // model.Data.Filters will be properly bound here
    ...
}

Thanks to editor templates you no longer have to write any foreach loops in your views or worry about how to name your input fields, invent some indexed, … so that the default model binder recognizes them on postback.