How to check if a class inherits another class without instantiating it? [duplicate]

Question

Suppose I have a class that looks like this:

class Derived : // some inheritance stuff here
{
}

I want to check something like this in my code:

Derived is SomeType;

But looks like is operator need Derived to be variable of type Dervied, not Derived itself. I don't want to create an object of type Derived.
How can I make sure Derived inherits SomeType without instantiating it?

P.S. If it helps, I want something like what where keyword does with generics.
EDIT:
Similar to this answer, but it's checking an object. I want to check the class itself.

Wernight · Accepted Answer · 2012-06-22 13:04:55Z

390

To check for assignability, you can use the Type.IsAssignableFrom method:

typeof(SomeType).IsAssignableFrom(typeof(Derived))

This will work as you expect for type-equality, inheritance-relationships and interface-implementations but not when you are looking for 'assignability' across explicit / implicit conversion operators.

To check for strict inheritance, you can use Type.IsSubclassOf:

typeof(Derived).IsSubclassOf(typeof(SomeType))

edited Jun 22, 2012 at 13:04

Wernight

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answered Jan 2, 2012 at 9:10

Ani

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5 Comments

Alex Hope O'Connor Over a year ago

Just as a note to anyone else wondering, this won't return true when checking against generic type/interface definitions, as far as I can tell you need to search the inheritance chain and check for generic type definitions yourself.

Douglas Gaskell Over a year ago

Alex, how would you go about searching the inheritance chain of a generic type to accomplish this?

Furkan Ekinci Over a year ago

@AlexHopeO'Connor's note is important and I think solution is there stackoverflow.com/questions/457676/…

Seafish Over a year ago

For PCL typeof(SomeType).GetTypeInfo().IsAssignableFrom(typeof(Derived).GetTypeInfo())

Issung Over a year ago

For those a little confused about the order, such as myself: typeof(InvalidOperationException).IsAssignableFrom(typeof(Exception)) = false typeof(Exception).IsAssignableFrom(typeof(InvalidOperationException)) = true

Haris Hasan · Accepted Answer · 2012-01-02 09:10:55Z

25

Try this

typeof(IFoo).IsAssignableFrom(typeof(BarClass));

This will tell you whether BarClass(Derived) implements IFoo(SomeType) or not

answered Jan 2, 2012 at 9:10

Haris Hasan

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