C# 将ViewModel传递给控制器不会'；我不能完全工作

我花了一整天的时间在网上搜索问题的解决方案，但是由于我的错误，我找不到解决方案。这是相当令人沮丧，我有一种感觉，这是一个脸掌的错误。我希望你们能抽出时间来帮我

我正在创建一个使用ViewModel的视图。我使用的是一个通知和提交输入类型按钮。现在，它传递ViewModel中的第一个属性，但其他所有属性都传递为null

这是我的视图模型+模型

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using FitnessSundhed.Models;
namespace FitnessSundhed.ViewModels
{
    public class WorkoutViewModel
    {
        public Workouts Workout { get; set; }
        public Sets Sets { get; set; }
        public Execises Execises { get; set; }
    }
}

这些属性中的一些应该是列表，但我选择在遇到问题之前不创建列表。别介意

以下是训练模式

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

namespace FitnessSundhed.Models
{
    public class Workouts
    {
        public int Id { get; set; }
        public string Name { get; set; }

        public string Author { get; set; }

        public string Description { get; set; }

        public string Equipment { get; set; }

        public string Targets { get; set; }

        public List<Sets> Sets { get; set; }


    }

}

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

namespace FitnessSundhed.Models
{
    public class Sets
    {
        public int Id { get; set; }
        public string SetName { get; set; }
        public string SetDesc { get; set; }

        public List<Execises> Execises { get; set; }
    }
}

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Web;

namespace FitnessSundhed.Models
{
    public class Execises
    {
        public int Id { get; set; }
        public string ImagePath { get; set; }
        public string Name { get; set; }
        public int Reps { get; set; }
        public string Note { get; set; }

    }
}

基本上，训练包含一个集合列表，其中包含一个执行列表

查看

@model FitnessSundhed.ViewModels.WorkoutViewModel

@{
    ViewBag.Title = "Action";
    Layout = "~/Views/Shared/_Layout.cshtml";
}

<h2>Action</h2>

@using (Html.BeginForm("Create", "Workouts", FormMethod.Post, null))
{
    @Html.AntiForgeryToken()

<div class="form-horizontal">
    <h4>Workouts</h4>
    <hr />
    @Html.ValidationSummary(true, "", new { @class = "text-danger" })
    <div class="form-group">
        @Html.LabelFor(model => model.Workout.Name, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.EditorFor(model => model.Workout.Name, new { htmlAttributes = new { @class = "form-control" } })
            @Html.ValidationMessageFor(model => model.Workout.Name, "", new { @class = "text-danger" })
        </div>
    </div>

    <div class="form-group">
        @Html.LabelFor(model => model.Workout.Author, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.EditorFor(model => model.Workout.Author, new { htmlAttributes = new { @class = "form-control" } })
            @Html.ValidationMessageFor(model => model.Workout.Author, "", new { @class = "text-danger" })
        </div>
    </div>

    <div class="form-group">
        @Html.LabelFor(model => model.Workout.Description, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.EditorFor(model => model.Workout.Description, new { htmlAttributes = new { @class = "form-control" } })
            @Html.ValidationMessageFor(model => model.Workout.Description, "", new { @class = "text-danger" })
        </div>
    </div>

    <div class="form-group">
        @Html.LabelFor(model => model.Workout.Equipment, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.EditorFor(model => model.Workout.Equipment, new { htmlAttributes = new { @class = "form-control" } })
            @Html.ValidationMessageFor(model => model.Workout.Equipment, "", new { @class = "text-danger" })
        </div>
    </div>

    <div class="form-group">
        @Html.LabelFor(model => model.Workout.Targets, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.EditorFor(model => model.Workout.Targets, new { htmlAttributes = new { @class = "form-control" } })
            @Html.ValidationMessageFor(model => model.Workout.Targets, "", new { @class = "text-danger" })
        </div>
    </div>


    <h4>Sets</h4>
    <hr />
    @Html.ValidationSummary(true, "", new { @class = "text-danger" })
    <div class="form-group">
        @Html.LabelFor(model => model.Sets.SetName, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.EditorFor(model => model.Sets.SetName, new { htmlAttributes = new { @class = "form-control" } })
            @Html.ValidationMessageFor(model => model.Sets.SetName, "", new { @class = "text-danger" })
        </div>
    </div>

    <div class="form-group">
        @Html.LabelFor(model => model.Sets.SetDesc, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.EditorFor(model => model.Sets.SetDesc, new { htmlAttributes = new { @class = "form-control" } })
            @Html.ValidationMessageFor(model => model.Sets.SetDesc, "", new { @class = "text-danger" })
        </div>
    </div>



    <div class="form-group">
        <div class="col-md-offset-2 col-md-10">
            <input type="submit" value="Create" class="btn btn-default" />
        </div>
    </div>
</div>
}

<div>
    @Html.ActionLink("Back to List", "Index")
</div>

Execes还没有被编码进去

总而言之。视图可以传递ViewModel，并且我可以将训练添加到数据库中（我以前已经这样做过），但是，当我尝试使用集合或Execes时，我在控制器中尝试将集合添加到训练中时会出现“System.NullReferenceException:“Object reference not set to a instance of a Object.”错误

---

我希望我已经详细描述了它。如果没有，请询问更多信息。

您的模型一开始只是一张白板

Workouts workout = new Workouts();

这意味着除非列表存在，否则无法将其添加到列表中。所以当你打电话的时候

workout.Sets.Add(model.Sets); // NullReferenceException here.

训练集为空。你的对象从不初始化它

在您的模型中执行此操作

public List<Sets> Sets { get; set; } = new List<Sets>();

公共列表集{get；set；}=new List（）；

相反，如果有时您不想初始化它（ORM绑定很生气或者其他什么），请确保在使用它之前调用它，就像这样

 Workouts workout = new Workouts();
            workout = model.Workout;
            workout.Sets = new List<Sets>();
            workout.Sets.Add(model.Sets); 

Workouts锻炼=新锻炼（）；
锻炼=模型锻炼；
workout.set=新列表（）；
锻炼。设置。添加（模型。设置）；

这是否回答了您的问题？你真漂亮！工作起来很有魅力！非常感谢你！！

 Workouts workout = new Workouts();
            workout = model.Workout;
            workout.Sets = new List<Sets>();
            workout.Sets.Add(model.Sets);