Question

My controller always gets “null” for the “adjModel” parameter.
How can I retrieve the values?

CONTROLLER

[HttpPost]
public ActionResult AdjustmentList(List<AdjustmentVM> adjModel)
{
   // adjModel is null
}

VIEW

@model List<ExtFramework.ViewModels.BillingArea.AdjustmentVM>

<div class="no-fancybox">
@using (Html.BeginForm("AdjustmentList", "Deposit", new { depositId = ViewBag.depositId }))
{
    <div>
        <table id="adjustment">
            <tr>
                <th>Description</th>
                <th>Montant</th>
            </tr>
            @foreach(var item in Model)
            {
                <tr>
                    <td>@Html.TextBoxFor(model => item.Description)</td>
                    <td>@Html.TextBoxFor(model => item.Amount)</td>
                </tr>
            }
        </table>
        <input type="submit" value="" class="save" />
    </div>
}
</div>

MODEL

namespace ExtFramework.ViewModels.BillingArea
{
    public class AdjustmentVM
    {
        public int AdjustmentId { get; set; }
        public string Description { get; set; }
        public decimal Amount { get; set; }
        public int DepositId { get; set; }
    }
}

Answer 1

This is where editor templates are useful. Instead of using a foreach loop to go through the list of view models, use @Html.EditorFor(m => m). Then, in a subfolder named EditorTemplates (an MVC naming convention) add a view with the name AdjustmentVM.cshtml. Again, this is another MVC naming convetion – using the name of the type being used. This file would look like:

@model AdjustmentVM

<tr>
    <td>@Html.TextBoxFor(model => model.Description)</td>
    <td>@Html.TextBoxFor(model => model.Amount)</td>
</tr>

The runtime will automatically loop over the items in the list and render the contents of the editor template, giving unique names for each form value, so that the default model binder can map these to the properties on the view model on postback.

You can customise the name of the editor template if you want, look a the UIHintAttribute class.