泛型T是类实现的接口 [英] Generics where T is class implementing interface

问题描述

我有一个接口：

interface IProfile { ... }

...和类：

...and a class:

[Serializable]
class Profile : IProfile 
{ 
  private Profile()
  { ... } //private to ensure only xmlserializer creates instances
}

...和方法的经理：

...and a manager with method:

class ProfileManager
{
  public T Load<T>(string profileName) where T : class, IProfile
  {
    using(var stream = new .......)
    {
      var ser = new XmlSerializer(typeof(T));
      return (T)ser.Deserialize(stream);
    }
  }
}

我希望使用这样的方法：

I expect the method to be used like this:

var profile = myManager.Load<Profile>("TestProfile"); // class implementing IProfile as T

...扔编译在这个时候错误：

...and throw compile time error on this:

var profile = myManager.Load<IProfile>("TestProfile"); // NO! IProfile interface entered!

不过一切编译，只有运行时错误被抛出的XmlSerializer 。

我想到了其中T：类将确保在那里只接受类类型

I thought the where T : class would ensure only class types where accepted?

是否有可能使编译器抛出一个异常 IProfile （或其他接口从 IProfile继承）进入，只有类型的课程实施 IProfile 接受？

Is it possible to make the compiler throw error if IProfile (or other interfaces inheriting from IProfile) is entered, and only types classes implementing IProfile are accepted?

推荐答案

根据 MSDN 类意味着T必须是引用类型;这也适用于任何类，接口，委托或数组类型。

According to MSDN class means that T must be a reference type; this applies also to any class, interface, delegate, or array type.

一个解决办法是要求那件T实现了参数较少的构造函数，因此：

One work around would be to require that T implements the parameter less constructor so:

where T : class, IProfile, new()

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