Get derived class type from a base's class static method

Question

i would like to get the type of the derived class from a static method of its base class.

How can this be accomplished?

Thanks!

class BaseClass {   static void Ping () {      Type t = this.GetType(); // should be DerivedClass, but it is not possible with a static method   } } class DerivedClass : BaseClass {}  // somewhere in the code DerivedClass.Ping(); 

Answer 1

This can be accomplished easily using the curiously recurring template pattern

class BaseClass<T>     where T : BaseClass<T> {     static void SomeMethod() {         var t = typeof(T);  // gets type of derived class     } }  class DerivedClass : BaseClass<DerivedClass> {} 

call the method:

DerivedClass.SomeMethod(); 

This solution adds a small amount of boilerplate overhead because you have to template the base class with the derived class.

It's also restrictive if your inheritance tree has more than two levels. In this case, you will have to choose whether to pass through the template argument or impose the current type on its children with respect to calls to your static method.

And by templates I, of course, mean generics.

Answer 2

If I'm not mistaken, the code emitted for BaseClass.Ping() and DerivedClass.Ping() is the same, so making the method static without giving it any arguments won't work. Try passing the type as an argument or through a generic type parameter (on which you can enforce an inheritance constraint).

class BaseClass {     static void Ping<T>() where T : BaseClass {         Type t = typeof(T);     } } 

You would call it like this:

BaseClass.Ping<DerivedClass>();