在属性中输入约束(Type constraints in Attributes)

在属性中输入约束(Type constraints in Attributes)

我想用自定义属性编写我的枚举，例如：

public enum SomeEnum: long { [SomeAttribute<MyClass1>] Sms = 1, [SomeAttribute<MyClass2>] Email = 2 }

但属性不支持泛型。 那么，最类似的解决方案是：

public enum SomeEnum: long { [SomeAttribute(typeof(MyClass1))] Sms = 1, [SomeAttribute(typeof(MyClass2))] Email = 2 }

这里是问题：我想要Class1从ICustomInterface继承，所以对于泛型我可以写约束：

[AttributeUsage(AttributeTargets.All)] class SomeAttribute<T> : Attribute where T: ICustomInterface { }

但属性不支持泛型。

所以最后的问题是：如何在编译时检查（如T约束）该类型是否正在实现一些接口？

I want to write my enum with custom attributes, for example:

public enum SomeEnum: long { [SomeAttribute<MyClass1>] Sms = 1, [SomeAttribute<MyClass2>] Email = 2 }

but attributes doesn't support generics. Well, the most similar solution is:

public enum SomeEnum: long { [SomeAttribute(typeof(MyClass1))] Sms = 1, [SomeAttribute(typeof(MyClass2))] Email = 2 }

And here is problem: I want Class1 to be inherited from ICustomInterface, so with generics I can write constraint:

[AttributeUsage(AttributeTargets.All)] class SomeAttribute<T> : Attribute where T: ICustomInterface { }

but attributes doesn't support generics.

so finally question is: how can I check in compile time (like T constraints) that type is implementing some interface?

最满意答案

对你最后的问题很简单：

所以最后的问题是：如何在编译时检查（如T约束）该类型是否正在实现一些接口？

你不能这样做。

但是你可以在运行时检查它，使用一些反射方法： Type.IsAssignableFrom

Very simple to your final question:

so finally question is: how can I check in compile time (like T constraints) that type is implementing some interface?

You can not do that.

But you can check it at runtime, with some reflection methods like: Type.IsAssignableFrom