Question

I have form which is made up of a List model. When the form is submitted back to action method, the list is null. How can I set this up?

public ActionResult PendingRenewals()
{
    //get list elements
    var customers = get customer that match our criteria;

    //Build list
    List<string[]> renewals = new List<string[]>();
    foreach(var item in customers)
    {
        renewals.Add(new string[] {item.name, item.id, item.PO });
    }
    return View(renewals);
}

View

   @model List<string[]>
   @using (Html.BeginForm()
   {
       <input type="submit" value="Save"/>
       <table>
           @foreach (var item in Model)
           {
               <tr>
                   <td>item[0]</td>
                   <td>item[1]</td>
                   <td>@Html.EditorFor(model => item[2])</td>
                   </td>
               </tr>
           }
    </table>
}

Back to Controller

[HttpPost]
public ActionResult PendingRenewals(List<string[]> renewal, string EntityId)
{
    //renewals is always null
    return PendingRenewals();
}

Solution

Using FortyTwo’s idea, I used a string[][] as the model, so the view looks like this (model[i][0]) and model[i][1] are the fields that I need passed back to the controller):

            @model string[][]
            @for (int i = 0; i < Model.Length; i++ )
            {
            <tr>
                <td>@Model[i][2]</td>
                <td>@Model[i][3]</td>
                <td>@Model[i][4]</td>
                <td>@Model[i][5]</td>
                <td>@Html.HiddenFor(model => model[i][0]) @Html.TextBoxFor(model => Model[i][1])</td>
            </tr>
        }

Answer 1

You need to use an old fashioned for loop. This way, the indexer is used to respect the naming conventions needed by mvc’s model binder.

@for (int i = 0; i < Model.Count; i++)
       {
           <tr>
               <td>Model[i].item[0]</td>
               <td>Model[i].item[1]</td>
               <td>@Html.EditorFor(model => model[i].item[2])</td>
               </td>
           </tr>
       }