MVC 3 ModelBinding使用ModelBinderAttribute的集合

Question

是否可以使用ModelBinderAttribute绑定到集合？

这里是我的操作方法参数：

[ModelBinder(typeof(SelectableLookupAllSelectedModelBinder))] List<SelectableLookup> classificationItems 

这是我的自定义模型粘合剂：

public class SelectableLookupAllSelectedModelBinder : IModelBinder 
{ 
    public object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext) 
    { 
     var model = bindingContext.Model as SelectableLookup ?? 
          (SelectableLookup)DependencyResolver.Current.GetService(typeof(SelectableLookup)); 

     model.UId = int.Parse(bindingContext.ValueProvider.GetValue(bindingContext.ModelName).AttemptedValue); 
     model.InitialState = true; 
     model.SelectedState = true; 

     return model; 
    } 
} 

下面是该参数的发布JSON数据：

"classificationItems":["19","20","21","22"]}

以下是ValueProvider看到它的方式：

viewModel.classificationItems[0] AttemptedValue = “19” viewModel.classificationItems[1] AttemptedValue = “20” viewModel.classificationItems[2] AttemptedValue = “21” viewModel.classificationItems[3] AttemptedValue = “22”

当前不工作，因为首先有一个前缀（ “视图模型” ）我可以理清，但其次bindingContext.ModelName是“classificationItems”这是参数的名称被绑定到，而不是列表中的索引项，即“分类项[0]”

我应该补充说，当我将此资料夹声明为全局ModelBin der in global.asax it works fine ...

Answer 1

您的自定义模型联编程序正用于整个列表，而不仅仅是针对每个特定项目。由于您正在通过实施IModelBinder从头开始编写新的联编程序，因此您需要处理将所有项目添加到列表和列表首选项等情况。这不是简单的代码，请检查DefaultModelBinder here。

相反，你可以扩展DefaultModelBinder类，让它照常上班，然后设置的2个属性为真：

public class SelectableLookupAllSelectedModelBinder: DefaultModelBinder 
{ 

    public override object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext) 
    { 
     //Let the default model binder do its work so the List<SelectableLookup> is recreated 
     object model = base.BindModel(controllerContext, bindingContext); 

     if (model == null) 
      return null; 

     List<SelectableLookup> lookupModel = model as List<SelectableLookup>; 
     if(lookupModel == null) 
      return model; 

     //The DefaultModelBinder has already done its job and model is of type List<SelectableLookup> 
     //Set both InitialState and SelectedState as true 
     foreach(var lookup in lookupModel) 
     { 
      lookup.InitialState = true; 
      lookup.SelectedState = true; 
     } 

     return model;   
    } 

前缀可以通过添加绑定属性的动作参数进行处理像[Bind(Prefix="viewModel")]

那么，到底你的操作方法参数会是什么样子：

[Bind(Prefix="viewModel")] 
[ModelBinder(typeof(SelectableLookupAllSelectedModelBinder))] 
List<SelectableLookup> classificationItems