Question

我正在制作我的MVC应用程序。我正在创建一个表格，里面有一个表格。一张桌子应该包含他们拥有的用户和成绩（如学校的标记表）。我希望标记可以修改，所以我使用默认值类型TextBox创建它们，就像在数据库中一样，但显然，当我按下＆＃34;应用更改＆＃34;按钮，控制器将所有标记的列表视为空。为什么会这样？
我的观点（其中的一部分）：

@Scripts.Render("~/bundles/jquery")
@Scripts.Render("~/bundles/bootstrap")
@model ClassDeclarationsThsesis.Models.ClassesViewViewModel


@{
    ViewBag.Title = "ClassesView";
}
<h2>ClassesView</h2>
<select id="sel">
    <option value="week">Current week</option>
    <option value="total">Total</option>
</select>
@{
    int i = 0;
    int inside = 0;
}
@using (Html.BeginForm("ClassesView", "Account", FormMethod.Post, new { @class = "form-horizontal", role = "form" }))
{
        <div id="week">
        <table border="1" width="500">
            <tr>
                <th>Surname</th>
                <th>Name</th>
                @foreach (var task in Model.current)
                {
                    <th>@task.name</th>
                }
                <th>Total</th>
            </tr>
            @{
                int counter = 0;
                int counter1 = 0;
            }
            @foreach (var user in Model.curr_users)
            {

                if (user.user_type.Replace(" ", String.Empty) == 1.ToString())
                {

                    <tr>
                        <th>@user.surname</th>
                        <th>@user.name</th>
                        @foreach (var task in Model.current)
                        {
                            foreach (var grade in Model.grading)
                            {
                                if (user.user_id == grade.user_id)
                                {
                                    if (task.task_id == grade.task_id)
                                    {
                                        inside = task.value;
                                        i = i + task.value;
                                        counter1++;
                                    }

                                }

                            }
                            <th>@Html.TextBoxFor(m => m.points[counter + counter1 - 1], new { @class = "form-control", @Value = @inside, style = "width:50px;" })</th>
                            inside = 0;
                        }
                        <th>
                            @i
                        </th>
                        @Html.HiddenFor(m => m.class_id)
                        @Html.HiddenFor(m => m.student_id)
                    </tr>
                }
                i = 0;
                counter++;
            }
        </table>
        <input type="submit" class="btn btn-default" value="Apply changes" />

    </div>
                }

我在此处使用的

points在List<int>中为ClassesViewViewModel。我做错了什么？
修改
添加了控制器：

public ActionResult ClassesView(ClassesViewViewModel value)
{
    ClassDeclarationsDBEntities4 entities = new ClassDeclarationsDBEntities4();
    ClassesViewViewModel model = new ClassesViewViewModel();
    model.users = entities.Users.ToList();
    model.tasks = entities.Tasks.ToList();
    model.group_id = value.group_id;
    model.class_id = value.class_id;
    model.grading = entities.Gradings.ToList();
    model.s_u = entities.Subjects_Users.ToList();
    model.t = new List<ClassDeclarationsThsesis.Classes.Task>();
    model.current = new List<ClassDeclarationsThsesis.Classes.Task>();
    model.curr_users = new List<ClassDeclarationsThsesis.Classes.User>();
    DateTime max = DateTime.MinValue;
    foreach (var task in model.tasks)
    {
        if (task.class_id == model.class_id)
        {
            model.t.Add(new ClassDeclarationsThsesis.Classes.Task(task.task_id, task.class_id, task.name, task.points, task.deadline));
        }


    }
    foreach (var task in model.t)
    {
        if (DateTime.Compare(task.deadline, max) > 0)
        {
            max = task.deadline;
        }
    }
    foreach (var task in model.t)
    {
        if (DateTime.Compare(task.deadline, max) == 0)
        {
            model.current.Add(task);
        }
    }
    foreach (var s_u in model.s_u)
    {
        if (s_u.class_id == model.class_id && s_u.group_id == model.group_id)
        {
            foreach (var user in model.users)
            {
                if (user.user_id == s_u.user_id)
                {
                    model.curr_users.Add(new ClassDeclarationsThsesis.Classes.User(user.name, user.surname, user.user_id, user.user_type, user.email, user.password));
                }

            }
        }

    }

    if (ModelState.IsValid)
    {
        for(int i=0;i<model.points.Count();i++)
        {
            //getting null here
        }
    }
    else
    {
        return View(model);
    }


    return View(model);
}

Answer 1

1）您应该在HttpPost操作方法中将“值”更改为“模型”。

public ActionResult ClassesView(ClassesViewViewModel model)

2）你的行动方法有很多方面。你应该学习存储库和服务模式。简而言之，你应该将db读取，插入，更新行放在存储库类中。你应该为每个实体创建存储库类。业务逻辑（验证等）必须在服务类中。

Answer 2

好的，我找到了答案。我将控制器中的value更改为model并更正了计数器以确保值是连续的，从0开始。感谢您的支持。

MVC视图返回null值

2 个答案: