您可以使用任何您拥有的信息。

You use whatever you have the information for.

您有一个要检查的实例和静态类型，请使用是

If you have an instance and a static type you want to check against, use is.

具有静态类型，你只有一个类型对象，但你有一个要检查的实例，使用 IsInstanceOfType 。

If you don't have the static type, you just have a Type object, but you have an instance you want to check, use IsInstanceOfType.

如果您没有实例，而只想检查类型$ c $的理论实例之间的兼容性c>和另一个类型，请使用 IsAssignableFrom 。

If you don't have an instance and you just want to check the compatibility between a theoretical instance of a Type and another Type, use IsAssignableFrom.

但实际上似乎你只是重新实现作为operator （除了你的也可以用于不可为null的值类型，这通常不是一个大的限制）。

But really is seems like you are just re-implementing the as operator (except that yours would also work for non-nullable value types, which is usually not a big limitation).