如何指定不实现特定接口的类型参数?

• where T : struct
• where T : class
• where T : SomeClassName
• where T : ISomeInterfaceName
• where T : U
• where T : new()

here

derivedClass.method() baseClass.method() derivedClass

public static T SomeMethod<T>(this object value) where T != IEnumerable
{
  if(typeof(T).GetInterface("IEnumerable") != null)
  {
    //behaviour appropriate for IEnumerable
  }
  else
  {
    //other behaviour.
  }
}

public static class XmlSerializableExtension {   
  public static string ToXml(this object self) { 
    // ...
  }
}

public interface MXmlSerializable { } 
public static class XmlSerializable {   
  public static string ToXml(this MXmlSerializable self) {
    // ...
  }
}

"mixin"

public class MyClass : MXmlSerializable { 
  // ...
}