Double Dispatch, Multiple Inheritance, and Shared Pointers - c++

Question

Is the following code the proper usage of shared_from_this - in the context of (multiple inheritance and proper reference counts)? The code is and implementation of the double dispatch visitor pattern where the interface accepts a shared pointer.
class EventIf;
typedef std::shared_ptr<EventIf> EventIfPtr;
class DispatchIF;
typedef std::shared_ptr<DispatchIF> DispatchIFPtr;
class EventOne;
typedef std::shared_ptr<EventOne> EventOnePtr;
class EventTwo;
typedef std::shared_ptr<EventTwo> EventTwoPtr;
class DispatchIF
{
public:
Dispatch(EventOnePtr pEvent){ std::cout << pEvent->GetType(); }
Dispatch(EventTwoPtr pEvent){ std::cout << pEvent->GetType() << pEvent->foo; }
};
class EventIf
{
public:
EventIf(theType) : type(theType) {}
virtual ~EventIf(){}
int GetType(){ return type; }
virtual void Accept(DispatchIFPtr pDispatcher) = 0;
protected:
int type;
};
cass EventOne : public EventIf, std::enable_shared_from_this<EventOne>
{
public:
EventOne() : EventIf(1) {}
virtual ~EventOne(){}
virtual void Accept(DispatchIFPtr pDispatcher){ pDispatcher->Dispatch(shared_from_this()); }
};
cass EventTwo : public EventIf, std::enable_shared_from_this<EventTwo>
{
public:
EventTwo() : EventIf(1) {}
virtual ~EventTwo(){}
virtual void Accept(DispatchIFPtr pDispatcher){ pDispatcher->Dispatch(shared_from_this()); }
public:
int foo;
};