我在另一个viewmodel中有一个viewmodel列表。 如何将参数从动作传递到控制器？

Question

I have a ViewModel containing a list of another ViewModel. I want to pass parameters to my controller. I can pass all viewmodel parameters but my list of second viewmodel is null.

This is my viewmodel:

public class Provider_Coupon_FullViewModel {
    public int pid { get; set; }
    public int cid { get; set; }
    public int crid { get; set; }
    public string opr_user { get; set; }
    public List<PackageDetailsViewModel> PackageDetails { get; set; }
}

public class PackageDetailsViewModel {
    public int packages_id { get; set; }
    public string package_title { get; set; }
}

And this is my razor page:

@model IList<myproject.Provider_Coupon_FullViewModel>
@using (Html.BeginForm())
{
    for (var i = 0; i < Model.Count; i++)
    {
    <div class="form-horizontal col-lg-12 col-md-12 col-sm-12 col-xs-12">           
        @Html.EditorFor(Model => Model[i].pid)
        @Html.EditorFor(Model => Model[i].cid)
        @Html.EditorFor(Model => Model[i].crid)

        /// I want show checkbox for list of viewmodel and pass value of them if check box checked
        @for (int j = 0; j < Model[i].PackageDetails.Count; j++)
        {
            <div class="col-lg-3 col-md-3 col-sm-3 col-xs-3 FormBox">
                <input type="checkbox" id=@Model[i].PackageDetails[j].packages_id name=@Model[i].PackageDetails[j].package_title value=@Model[i].PackageDetails[j].packages_id class="check">
                <label for="@Model[i].PackageDetails[j].packages_id">@Model[i].PackageDetails[j].package_title</label>
            </div> 
        }
        @for (int j = 0; j < Model[i].PackageDetails.Count; j++)
        {
            <div class="col-lg-3 col-md-3 col-sm-3 col-xs-3 FormBox">
                <input type="checkbox" id=@Model[i].PackageDetails[j].packages_id name=@Model[i].PackageDetails[j].package_title value=@Model[i].PackageDetails[j].packages_id class="check">
                <label for="@Model[i].PackageDetails[j].packages_id">@Model[i].PackageDetails[j].package_title</label>
            </div>
        }
    </div>
    }
}

Answer 1

Instead of rendering the checkboxes yourself, you should let MVC handle that by using Html.CheckBoxFor(m => ...) . MVC will generate form element names that exactly match what it needs when the posted data is being parsed, which is very hard to do for yourself.

Also, to render a checkbox this way you need to have a bool property in your ViewModel, but that is missing.

What follows is working code (actually tested).

(Before we continue, one more essential thing: don't use foreach as the comment above states. Reason: MVC CheckBoxFor() only generates proper form element names (that can be parsed by MVC again) if you use for + [indexes] at all levels of the ViewModel, whereas that ability would fall apart if you'd use foreach at any level. MVC needs and uses those index numbers.)

Controller:

using System.Collections.Generic;
using System.Linq;
using System.Web.Mvc;

namespace Test_MVC.Controllers
{
    public class TestController : Controller
    {
        [HttpGet]
        public ActionResult Index()
        {
            // Create some data for initial display
            var packageModels1 = new[] {
                new PackageDetailsViewModel { packages_id = 101, package_title = "Order 101", is_selected = false },
                new PackageDetailsViewModel { packages_id = 102, package_title = "Order 102", is_selected = true },
                new PackageDetailsViewModel { packages_id = 103, package_title = "Order 103", is_selected = false }
            };
            var packageModels2 = new[] {
                new PackageDetailsViewModel { packages_id = 201, package_title = "Order 201", is_selected = false },
                new PackageDetailsViewModel { packages_id = 202, package_title = "Order 202", is_selected = false }
            };
            var couponModels = new[] {
                new Provider_Coupon_FullViewModel { cid = 1, crid = 2, opr_user = "John", pid = 4, PackageDetails = packageModels1.ToList() },
                new Provider_Coupon_FullViewModel { cid = 7, crid = 8, opr_user = "Beth", pid = 6, PackageDetails = packageModels2.ToList() }
            };

            return View(couponModels.ToList());
        }

        [HttpPost]
        public ActionResult Index(List<Provider_Coupon_FullViewModel> model)
        {
            // Pass whatever was posted & parsed right back into the view for verification
            return View(model);
        }
    }
}

ViewModel classes:

public class Provider_Coupon_FullViewModel
{
    public int pid { get; set; }
    public int cid { get; set; }
    public int crid { get; set; }
    public string opr_user { get; set; }
    public List<PackageDetailsViewModel> PackageDetails { get; set; }
}

public class PackageDetailsViewModel
{
    public int packages_id { get; set; }
    public string package_title { get; set; }
    public bool is_selected { get; set; } /////// <--- BOOL PROPERTY <--- ///////
}

Razor View:

@model IList<Provider_Coupon_FullViewModel>
@using (Html.BeginForm())
{
    for (var i = 0; i < Model.Count; i++)
    {
        <div style="border: dashed 1px blue; margin: 5px; padding: 5px">
            pid: @Html.EditorFor(Model => Model[i].pid)<br />
            cid: @Html.EditorFor(Model => Model[i].cid)<br />
            crid: @Html.EditorFor(Model => Model[i].crid)<br />

            @*I want show checkbox for list of viewmodel and pass value of them if check box checked*@
            @for (int j = 0; j < Model[i].PackageDetails.Count; j++)
            {
                <div class="">
                    i = @i / j = @j / ID: @Html.DisplayFor(m => Model[i].PackageDetails[j].packages_id) / Title: @Html.DisplayFor(m => Model[i].PackageDetails[j].package_title) /
                    @Html.CheckBoxFor(m => Model[i].PackageDetails[j].is_selected)
                    @Html.LabelFor(m => Model[i].PackageDetails[j].is_selected)
                </div>
            }
        </div>
    }
    <input type="submit" value="Submit" />
}