单个视图中的多个模型 (C# MVC3)

Question

我正在使用 C# 和 MVC3。

我有一个页面，例如一个学生列表，它显示了数据库驱动的学生列表。同时我的菜单是数据库驱动的，所以我还必须将它发送到视图。

如何将两个模型发送到一个视图？

Answer 1

您应该始终为您的视图创建单独的 ViewModel。从你的视图到你的领域模型应该有一个抽象。在演示/教程中，他们通过简单地将视图强输入到领域模型来展示这一切都非常简单，但这不是一个好的策略。视图不应依赖于业务对象。

即使需要将域模型映射到另一个视图模型类，您也应该为当前场景以及所有其他视图实施 David Glenn 提出的解决方案。

编辑：

如果你有一个顶级菜单 > TopMenu.aspx 而且你里面有多个局部视图 > StudentMenu.ascx, ResultMenu.ascx

您将为顶部菜单创建一个视图模型 > TopMenuViewModel.cs 您还将为局部视图创建视图模型 > StudentMenuViewModel 、 ResultMenuViewModel 等。

而您的 TopMenuViewModel 将同时拥有 >

class TopMenuViewModel 
{
   //all the stuff required in TopMenu.aspx
   StudentMenuViewModel studentvm;
   ResultMenuViewModel resultvm;
}

在TopMenu.aspx 渲染部分时，您将传递相关的视图模型>

Html.RenderPartial('StudentView', Model.studentvm)

希望有意义

Answer 2

您可以创建一个 ViewModel，它代表您的视图而不是您的业务模型

public class StudentPage {

  public IEnumerable<Student> Students { get; set; }

  public Menu Menu { get; set; }

}

然后您的控制器将 ViewModel 返回到您的视图

public ViewResult Students() {

   var menu = GetMenu();
   var students = Repository.Students();

   var model = new StudentPage {
     Menu = menu,
     Students = students
   }

   return View(model);

}

我假设菜单是您页面上重复出现的功能，因此您可能希望将其分解为有点像

public class BasePage {

  public Menu Menu { get; set; }

}

public class StudentPage : BasePage {

  public IEnumerable<Student> Students { get; set; }

}

您还可以创建一个具有GetMenu() 功能的基本控制器，以便跨多个控制器重复使用。

Answer 3

注意：以下类应在 .net 3.5 及更低版本中使用，因为 .net 4 引入了类似的名为 Tuple 的类，应改为使用。

MultiObject<O1, O2, ..> 和 MultiList<L1, L2, ...>

这就是我编写此类控制器操作和视图的方式：

public ActionResult MultiModel()
{
    MultiList<User, Company> result = MultiList.New(
        this.repository.GetUsers(),
        this.repository.GetCompanies()
    );
    return View(result);
}

我的观点是这样的：

ViewPage<MultiList<User, Company>>

我正在使用这个可重用的便利类：

#region MultiObject static helper class

/// <summary>
/// Provides static methods for creating multi objects with type inference.
/// </summary>
[SuppressMessage("Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly", MessageId = "Multi")]
public static class MultiObject
{
    /// <summary>
    /// Creates a new <see cref="MultiObject{T1, T2}"/> object instance.
    /// </summary>
    /// <typeparam name="T1">The type of the first object.</typeparam>
    /// <typeparam name="T2">The type of the second object.</typeparam>
    /// <param name="first"><typeparamref name="T1"/> object instance.</param>
    /// <param name="second"><typeparamref name="T2"/> object instance.</param>
    /// <returns>
    /// Returns a <see cref="MultiObject{T1, T2}"/> of <typeparamref name="T1"/> and <typeparamref name="T2"/> object instances.
    /// </returns>
    public static MultiObject<T1, T2> New<T1, T2>(T1 first, T2 second)
    {
        return new MultiObject<T1, T2>(first, second);
    }

    /// <summary>
    /// Creates a new <see cref="MultiObject{T1, T2, T3}"/> object instance.
    /// </summary>
    /// <typeparam name="T1">The type of the first object.</typeparam>
    /// <typeparam name="T2">The type of the second object.</typeparam>
    /// <typeparam name="T3">The type of the third object.</typeparam>
    /// <param name="first"><typeparamref name="T1"/> object instance.</param>
    /// <param name="second"><typeparamref name="T2"/> object instance.</param>
    /// <param name="third"><typeparamref name="T3"/> object instance.</param>
    /// <returns>
    /// Returns a <see cref="MultiObject{T1, T2, T3}"/> of <typeparamref name="T1"/>, <typeparamref name="T2"/> and <typeparamref name="T3"/> objects instances.
    /// </returns>
    public static MultiObject<T1, T2, T3> New<T1, T2, T3>(T1 first, T2 second, T3 third)
    {
        return new MultiObject<T1, T2, T3>(first, second, third);
    }
}

#endregion

#region MultiObject<T1, T2>

/// <summary>
/// Represents a 2-multi object, or pair.
/// </summary>
/// <typeparam name="T1">The type of the multi object's first component.</typeparam>
/// <typeparam name="T2">The type of the multi object's second component.</typeparam>
[SuppressMessage("Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly", MessageId = "Multi")]
public class MultiObject<T1, T2>
{
    /// <summary>
    /// Gets or sets the value of the first multi object component.
    /// </summary>
    /// <value>The first.</value>
    public T1 First { get; set; }

    /// <summary>
    /// Gets or sets the value of the second multi object component.
    /// </summary>
    /// <value>The second multi object component value.</value>
    public T2 Second { get; set; }

    /// <summary>
    /// Initializes a new instance of the <see cref="MultiObject{T1, T2}"/> class.
    /// </summary>
    /// <param name="first">Multi object's first component value.</param>
    /// <param name="second">Multi object's second component value.</param>
    public MultiObject(T1 first, T2 second)
    {
        this.First = first;
        this.Second = second;
    }
}

#endregion

#region MultiObject<T1, T2, T3>

/// <summary>
/// Creates a new 3-multi object, or triple.
/// </summary>
/// <typeparam name="T1">The value of the first component of the multi object.</typeparam>
/// <typeparam name="T2">The value of the second component of the multi object.</typeparam>
/// <typeparam name="T3">The value of the third component of the multi object.</typeparam>
[SuppressMessage("Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly", MessageId = "Multi")]
[SuppressMessage("Microsoft.Design", "CA1005:AvoidExcessiveParametersOnGenericTypes")]
public class MultiObject<T1, T2, T3> : MultiObject<T1, T2>
{
    /// <summary>
    /// Gets or sets the value of the third multi object component.
    /// </summary>
    /// <value>The third multi object component value.</value>
    public T3 Third { get; set; }

    /// <summary>
    /// Initializes a new instance of the <see cref="MultiObject{T1, T2, T3}"/> class.
    /// </summary>
    /// <param name="first">Multi object's first component value.</param>
    /// <param name="second">Multi object's second component value.</param>
    /// <param name="third">Multi object's third component value.</param>
    public MultiObject(T1 first, T2 second, T3 third)
        : base(first, second)
    {
        this.Third = third;
    }
}

#endregion

当我必须传递多个列表时

#region MultiObject static helper class

/// <summary>
/// Provides static methods for creating multi objects with type inference.
/// </summary>
[SuppressMessage("Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly", MessageId = "Multi")]
public static class MultiList
{
    /// <summary>
    /// Creates a new <see cref="MultiObject{T1, T2}"/> object instance.
    /// </summary>
    /// <typeparam name="T1">The type of the first object.</typeparam>
    /// <typeparam name="T2">The type of the second object.</typeparam>
    /// <param name="first"><typeparamref name="T1"/> object instance.</param>
    /// <param name="second"><typeparamref name="T2"/> object instance.</param>
    /// <returns>
    /// Returns a <see cref="MultiObject{T1, T2}"/> of <typeparamref name="T1"/> and <typeparamref name="T2"/> object instances.
    /// </returns>
    public static MultiList<T1, T2> New<T1, T2>(IList<T1> first, IList<T2> second)
    {
        return new MultiList<T1, T2>(first, second);
    }

    /// <summary>
    /// Creates a new <see cref="MultiObject{T1, T2, T3}"/> object instance.
    /// </summary>
    /// <typeparam name="T1">The type of the first object.</typeparam>
    /// <typeparam name="T2">The type of the second object.</typeparam>
    /// <typeparam name="T3">The type of the third object.</typeparam>
    /// <param name="first"><typeparamref name="T1"/> object instance.</param>
    /// <param name="second"><typeparamref name="T2"/> object instance.</param>
    /// <param name="third"><typeparamref name="T3"/> object instance.</param>
    /// <returns>
    /// Returns a <see cref="MultiObject{T1, T2, T3}"/> of <typeparamref name="T1"/>, <typeparamref name="T2"/> and <typeparamref name="T3"/> objects instances.
    /// </returns>
    public static MultiList<T1, T2, T3> New<T1, T2, T3>(IList<T1> first, IList<T2> second, IList<T3> third)
    {
        return new MultiList<T1, T2, T3>(first, second, third);
    }
}

#endregion

#region MultiList<T1, T2>

/// <summary>
/// Represents a 2-multi object, or pair.
/// </summary>
/// <typeparam name="T1">The type of the multi object's first component.</typeparam>
/// <typeparam name="T2">The type of the multi object's second component.</typeparam>
[SuppressMessage("Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly", MessageId = "Multi")]
public class MultiList<T1, T2> : MultiObject<IList<T1>, IList<T2>>
{
    /// <summary>
    /// Initializes a new instance of the <see cref="MultiList&lt;T1, T2&gt;"/> class.
    /// </summary>
    /// <param name="first">The first.</param>
    /// <param name="second">The second.</param>
    public MultiList(IList<T1> first, IList<T2> second) : base(first, second) { }
}

#endregion

#region MultiList<T1, T2, T3>

/// <summary>
/// Creates a new 3-multi object, or triple.
/// </summary>
/// <typeparam name="T1">The value of the first component of the multi object.</typeparam>
/// <typeparam name="T2">The value of the second component of the multi object.</typeparam>
/// <typeparam name="T3">The value of the third component of the multi object.</typeparam>
[SuppressMessage("Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly", MessageId = "Multi")]
[SuppressMessage("Microsoft.Design", "CA1005:AvoidExcessiveParametersOnGenericTypes")]
public class MultiList<T1, T2, T3> : MultiObject<IList<T1>, IList<T2>, IList<T3>>
{
    /// <summary>
    /// Initializes a new instance of the <see cref="MultiList&lt;T1, T2, T3&gt;"/> class.
    /// </summary>
    /// <param name="first">The first.</param>
    /// <param name="second">The second.</param>
    /// <param name="third">The third.</param>
    public MultiList(IList<T1> first, IList<T2> second, IList<T3> third) : base(first, second, third) { }
}

#endregion

每个视图的数据

但是在您想要传递菜单的情况下，最好有一个您的所有页面都继承自的基本页面类，并且该页面类提供所有常见属性（菜单数据是一个）。

Answer 4

为了在单个视图中处理多个模型，我个人使用 ViewBag。

请注意，如果您使用 ViewBag，则您从编译器获得的所有帮助都将被禁用，并且运行时错误/错误发生的可能性要高于该属性位于“正常”对象上并且编译器会捕捉到拼写错误的情况.

这是使用动态对象的缺点，但是，还有许多其他优点。在您的控制器中，您只需将数据/模型传递到 ViewBag：

public ActionResult Index() {
            ViewBag.TopMenu = TopMenu();
            ViewBag.Student = Student();
            return View();
        }

然后在视图中，把它们叫出来：

@{
    ViewBag.Title = "Index_ViewBag";
}

<h2>Index View Bag</h2>

<table>
   <tr>
   @foreach (var menu in ViewBag.TopMenu) 
   {
      <td>
      <a href="@menu.URL">@menu.Name</a>
      </td>
   }
   </tr>
</table>

<p>
 <ul>
  @foreach (var student in ViewBag.Student) 
  {
   <li>
    <a href="@student.URL">@student.Name</a>
   </li>   
  }
 </ul>
</p>

Answer 5

对此还有另一种选择，它被一些 MVC 纯粹主义者提出，但我发现它对我很有效。您可以在学生视图中像这样显示您的菜单，而不是在您有“菜单”的每个页面上都包含这两个模型（我假设几乎是所有页面）：

@Html.RenderAction("Menu");

这将调用它自己的操作，生成菜单视图模型和“菜单”部分视图。

对我来说，这是有道理的，但我知道很多人不喜欢它。

Answer 6

在 .Net Framework 4.0 中，您可以使用动态模型。

大概：

public class HomeController : Controller
{
    public ActionResult Index()
    {
        dynamic viewmodel = new ExpandoObject();
        viewmodel.Students = MyStudent();
        viewmodel.MenuItems = MyMenuItems();
        return View(mymodel);
    }
}

如何在视图代码中访问：

@model dynamic

@foreach (Student student in Model.Students)
    }
        <h1>@student.Name</h1>
    }
@foreach (MenuItem menuItem in Model.MenuItems)
    {
        <h1>@menuItem.menuname</h1>
    }