C# MVC Model Binding for List<T>-CodePudding

I am trying to create a form in C# MVC for a practice restaurant app with model binding. I am having a bit of a difficult time comprehending what it is exactly that I am doing wrong or how to do it. I have a form of OrderItems and a quantity. I want to make models with the quantities so that I can make the corresponding order rows in the database.

The Form (It is a Partial View):

@using FormAddOrderItemModel = Restaurant.Models.Order.Form.FormAddOrderItemModel
@model FormAddOrderItemModel;

@using (Html.BeginForm("Form_AddOrderItems", "Order", FormMethod.Post))
{
    for (var i = 0; i < Model.OrderItems.Count; i  )
    {
        var item = Model.OrderItems[i];
        <div>
            @Html.Label(item.Name)
            @Html.HiddenFor(m => m.ContentsList[i].OrderItem, item)
            @Html.LabelFor(m => m.ContentsList[i].Quantity)
            @Html.TextBoxFor(m => m.ContentsList[i].Quantity)
        </div>
    }
    <input class="btn btn-primary" type="submit" value="Submit">
}

The Model:

using System.Collections.Generic;

namespace Restaurant.Models.Order.Form
{
    public class FormAddOrderItemModel
    {
        public List<OrderItem> OrderItems { get; set; }
        public List<FormContents> ContentsList { get; set; }
    }
    
    public class FormContents
    {
        public OrderItem OrderItem { get; set; }
        public int Quantity { get; set; }
    }
}

The Controller Action:

[HttpPost]
public IActionResult Form_AddOrderItems(List<FormContents> response) {
    var test = response;
    
    return View("ManageOrder", _orderService.PrepareManageOrderViewModel(12));
}

I was under the assumption that this would populate a list of FormContents. The 'response' in the Controller Action is an instantiated List of FormContents with a count of 0.

How can I pass a List of FormContents from my Partial View to my Controller?

CodePudding user response：

since you are submitting a form , the input parameter of the action should be the same as the form model

public IActionResult Form_AddOrderItems(FormAddOrderItemModel model)

and your view model can be simplier

@model Restaurant.Models.Order.Form.FormAddOrderItemModel