mvc3 razor editortemplate与抽象类

Question

这是MVC3 Razor httppost返回复杂对象子集合的后续问题.

我给出的例子非常简单.子集合实际上是一个对象集合,它们都来自抽象基类.所以集合有一个基类列表.

我已经为每个派生类创建了一个模板,并尝试使用if子类型,然后将模板名称作为字符串.模板将呈现给视图,但不会在帖子后面填充.

我不确定如何使用编辑器对模板进行选择正确的模板,并将信息编组回父容器中的子对象.

Answer 1

您可以使用自定义模型绑定器.我们来举个例子吧.

模型:

public class MyViewModel
{
    public IList<BaseClass> Children { get; set; }
}

public abstract class BaseClass
{
    public int Id { get; set; }

    [HiddenInput(DisplayValue = false)]
    public string ModelType
    {
        get { return GetType().FullName; }
    }
}

public class Derived1 : BaseClass
{
    public string Derived1Property { get; set; }
}

public class Derived2 : BaseClass
{
    public string Derived2Property { get; set; }
}

控制器:

public class HomeController : Controller
{
    public ActionResult Index()
    {
        var model = new MyViewModel
        {
            Children = new BaseClass[]
            {
                new Derived1 { Id = 1, Derived1Property = "prop1" },
                new Derived2 { Id = 2, Derived2Property = "prop2" },
            }
        };
        return View(model);
    }

    [HttpPost]
    public ActionResult Index(MyViewModel model)
    {
        // everything will be fine and dandy here
        ...
    }
}

查看(~/Views/Home/Index.cshtml):

@model MyViewModel

@using (Html.BeginForm())
{
    for (int i = 0; i < Model.Children.Count; i++)
    {
        @Html.EditorFor(x => x.Children[i].ModelType)
        <div>
            @Html.EditorFor(x => x.Children[i].Id)
            @Html.EditorFor(x => x.Children[i])    
        </div>
    }

    <button type="submit">OK</button>
}

Dervied1type(~/Views/Home/EditorTemplates/Derived1.cshtml)的编辑器模板:

@model Derived1
@Html.EditorFor(x => x.Derived1Property)

和Dervied2type(~/Views/Home/EditorTemplates/Derived2.cshtml)的编辑器模板:

@model Derived2
@Html.EditorFor(x => x.Derived2Property)

现在剩下的就是一个自定义模型绑定器,它将使用隐藏字段值来实例化集合中的正确类型:

public class BaseClassModelBinder : DefaultModelBinder
{
    protected override object CreateModel(ControllerContext controllerContext, ModelBindingContext bindingContext, Type modelType)
    {
        var typeValue = bindingContext.ValueProvider.GetValue(bindingContext.ModelName + ".ModelType");
        var type = Type.GetType(
            (string)typeValue.ConvertTo(typeof(string)),
            true
        );
        var model = Activator.CreateInstance(type);
        bindingContext.ModelMetadata = ModelMetadataProviders.Current.GetMetadataForType(() => model, type);
        return model;
    }
}

将在以下地址注册Application_Start:

ModelBinders.Binders.Add(typeof(BaseClass), new BaseClassModelBinder());