在 C# 中使用带有泛型的 `is` 运算符

Question

I want to do something like this:

class SomeClass<T>
{
   SomeClass()
   {
        bool IsInterface = T is ISomeInterface;
   }
}

What is the best way for something like this?

Note: I am not looking to constrain T with a where , but I would like my code to be aware of what types of interfaces T implements. I would prefer that I don't have to construct a T .

Answer 1

I don't think you can use the is operator for this. But you can use IsAssignableFrom:

bool IsInterface = typeof(ISomeInterface).IsAssignableFrom(typeof(T));

Answer 2

should use following instead

 bool IsInterface = typeof(ISomeInterface).IsAssignableFrom(typeof(T));

is operator

is operator is used to check whether the run-time type of an object is compatible with a given type .

An expression where the use of is conforms to the syntax, evaluates to true, if both of the following conditions are met:

• expression is not null.
• expression can be cast to type. That is, a cast expression of the form (type)(expression) will complete without throwing an exception. For more information, see 7.6.6 Cast expressions.

---

References

• Does a Type Implement an Interface?
• is operator

Answer 3

You can use IsAssignableFrom :

  class SomeClass<T>
  {
     SomeClass()
     {
        bool IsIComparable = typeof(IComparable).IsAssignableFrom(typeof(T));
     }
  } 

Answer 4

bool IsInterface = typeof(ISomeInterface).IsAssignableFrom(typeof(T))

Answer 5

我相信你能做到最好：

bool IsInterface = typeof(ISomeInterface).IsAssignableFrom(typeof(T));

Answer 6

You could try doing something like

Type Ttype = typeof(T);

That will give you the full power of the Type class, which has functions like "FindInterfaces".