ado.net mvc3 元组在模型和单个视图中使用 [英] ado.net mvc3 tuple using in model and single views

问题描述

我有以下 ADO 模型

学生身份证、姓名和课程Id,Name,Student_ID

我为它做了如下视图

@model 元组

它的控制器如下

public ActionResult Create(){返回视图()；}////POST:/Default3/创建[HttpPost]public ActionResult Create(Tuplet){尝试{//TODO: 在此处添加插入逻辑db.Students.AddObject(t.Item1);db.SaveChanges();t.Item2.S_ID = t.Item1.Id；db.Courses.AddObject(t.Item2);db.SaveChanges();return RedirectToAction("复制");}抓住{返回视图()；}}

但是当我点击创建按钮时，它会给出以下错误

<块引用><块引用>

/"应用程序中的服务器错误.

没有为此对象定义无参数构造函数.

解决方案

Tuple<X, Y> 类没有默认构造函数，所以如果你想让它工作，你需要编写一个自定义模型绑定器.另一种可能性是使用我建议您使用的自定义视图模型:

公共类 MyViewModel{公共课程课程{得到;放;}公共学生学生{得到;放;}}

然后:

public ActionResult Create(){返回视图(新的 MyViewModel())；}////POST:/Default3/创建[HttpPost]公共 ActionResult 创建(MyViewModel 模型){尝试{//TODO: 在此处添加插入逻辑db.Students.AddObject(t.Student);db.SaveChanges();t.Course.S_ID = t.Student.Id；db.Courses.AddObject(t.Course);db.SaveChanges();return RedirectToAction("复制");}抓住{返回视图(模型)；}}

最后:

@model MvcApplication4.Models.MyViewModel@{ViewBag.Title = "创建";}<h2>创建</h2>@using (Html.BeginForm()) {@Html.ValidationSummary(true)<字段集><传奇>课程</传奇><div class="编辑器标签">@Html.LabelFor(model => model.Student.Name)</div><div class="编辑器字段">@Html.EditorFor(model => model.Student.Name)@Html.ValidationMessageFor(model => model.Student.Name)</div><div class="编辑器标签">@Html.LabelFor(model => model.Student.S_ID, "学生")</div><字段集><传奇>学生</传奇><div class="编辑器标签">@Html.LabelFor(model => model.Course.Name)</div><div class="编辑器字段">@Html.EditorFor(model => model.Course.Name)@Html.ValidationMessageFor(model => model.Course.Name)</div><div class="编辑器标签">@Html.LabelFor(model => model.Course.Class)</div><div class="编辑器字段">@Html.EditorFor(model => model.Course.Class)@Html.ValidationMessageFor(model => model.Course.Class)</div><p><输入类型=提交"值=创建"/></p></字段集>}

I have the following ADO Model

Student Id,Name and Course Id,Name,Student_ID

I have made the following view for it

@model Tuple<MvcApplication4.Models.Course, MvcApplication4.Models.Student >
@{
    ViewBag.Title = "Create";
}
<h2>Create</h2>
@using (Html.BeginForm()) {
    @Html.ValidationSummary(true)
    <fieldset>
        <legend>Course</legend>

        <div class="editor-label">
            @Html.LabelFor(model => model.Item1.Name)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.Item1.Name)
            @Html.ValidationMessageFor(model => model.Item1.Name)
        </div>
        <div class="editor-label">
            @Html.LabelFor(model => model.Item1.S_ID, "Student")
        </div>
            <fieldset>
        <legend>Student</legend>

        <div class="editor-label">
            @Html.LabelFor(model => model.Item2.Name)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.Item2.Name)
            @Html.ValidationMessageFor(model => model.Item2.Name)
        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.Item2.Class)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.Item2.Class)
            @Html.ValidationMessageFor(model => model.Item2.Class)
        </div>

        <p>
            <input type="submit" value="Create" />
        </p>
    </fieldset>

    </fieldset>
}

And the controller for it is as

public ActionResult Create()
{
      return View();
} 

//
// POST: /Default3/Create

[HttpPost]
public ActionResult Create(Tuple<Student ,Course > t)
{

    try
    {
        // TODO: Add insert logic here

        db.Students.AddObject(t.Item1);
        db.SaveChanges();

        t.Item2.S_ID = t.Item1.Id;
        db.Courses.AddObject(t.Item2);
        db.SaveChanges();

        return RedirectToAction("Copy");
    }
    catch
    {
        return View();
    }
}

But When i click the Creat button it gives the following Error

Server Error in '/' Application.

No parameterless constructor defined for this object.

解决方案

The Tuple<X, Y> class doesn't have a default constructor so you will need to write a custom model binder if you want this to work. Another possibility is to use a custom view model which is what I would recommend you:

public class MyViewModel
{
    public Course Course { get; set; }
    public Student Student { get; set; }
}

and then:

public ActionResult Create()
{
    return View(new MyViewModel());
} 

//
// POST: /Default3/Create

[HttpPost]
public ActionResult Create(MyViewModel model)
{
    try
    {
        // TODO: Add insert logic here
        db.Students.AddObject(t.Student);
        db.SaveChanges();

        t.Course.S_ID = t.Student.Id;
        db.Courses.AddObject(t.Course);
        db.SaveChanges();

        return RedirectToAction("Copy");
    }
    catch
    {
        return View(model);
    }
}

and finally:

@model MvcApplication4.Models.MyViewModel
@{
    ViewBag.Title = "Create";
}
<h2>Create</h2>
@using (Html.BeginForm()) {
    @Html.ValidationSummary(true)
    <fieldset>
        <legend>Course</legend>

        <div class="editor-label">
            @Html.LabelFor(model => model.Student.Name)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.Student.Name)
            @Html.ValidationMessageFor(model => model.Student.Name)
        </div>
        <div class="editor-label">
            @Html.LabelFor(model => model.Student.S_ID, "Student")
        </div>
            <fieldset>
        <legend>Student</legend>

        <div class="editor-label">
            @Html.LabelFor(model => model.Course.Name)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.Course.Name)
            @Html.ValidationMessageFor(model => model.Course.Name)
        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.Course.Class)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.Course.Class)
            @Html.ValidationMessageFor(model => model.Course.Class)
        </div>

        <p>
            <input type="submit" value="Create" />
        </p>
    </fieldset>
}

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