当类型是可空不叫自定义模型绑定 [英] Custom model binder not called when type is nullable

问题描述

我有调用自定义结构的TimeOfDay 这是在这样的视图模型中：

I have a custom struct called TimeOfDay which is used in a view model like this:

public class MyViewModel
{
  public TimeOfDay TimeOfDay { get; set; }
}

我创建了一个叫做 TimeOfDayModelBinder 自定义模型粘结剂和Global.asax.cs中注册这样的：

I have created a custom model binder called TimeOfDayModelBinder and registered it in Global.asax.cs like this:

ModelBinders.Binders.Add(typeof(TimeOfDay), new TimeOfDayModelBinder());

和一切伟大工程。但是，如果我改变我的视图模型这样：

And everything works great. However, if I change my view model to this:

public class MyViewModel
{
  public TimeOfDay? TimeOfDay { get; set; } // Now nullable!
}

我的自定义模型粘合剂不再叫。我知道，物业不再是一个类型的TimeOfDay，但可空这是不同的。因此，这是否意味着我应该补充的两倍我的自定义模型绑定在Global.asax.cs中是这样的：

My custom model binder is no longer called. I know that the property is no longer a type of TimeOfDay, but a Nullable which is different. So does this mean I should add my custom model binder twice in Global.asax.cs like this:

ModelBinders.Binders.Add(typeof(TimeOfDay), new TimeOfDayModelBinder());
ModelBinders.Binders.Add(typeof(TimeOfDay?), new TimeOfDayModelBinder());

它的工作原理，但这里还有一些我不喜欢它。这真的有必要处理我喜欢的类型为可为空，或者是有什么我失踪？

It works, but there's just something I don't like about it. Is this really necessary to handle my type as nullable, or is there something I'm missing?

推荐答案

每@ LukeH的评论，现在看来，这是必要的。我想这是有道理的太多，因为的TimeOfDay 和可空＆LT;的TimeOfDay＆GT; 确实是两种不同类型的CLR。所以我想我必须忍受它。 ： - ）

Per @LukeH's comment, it seems it is necessary. I guess that makes sense too, as TimeOfDay and Nullable<TimeOfDay> really is two different types in the CLR. So I guess I have to live with it. :-)

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