Introduction
Ben Chan introduced a way of simulating delegates in unmanaged code.
Although his method works I wanted to have a syntax similar found in the C# language. I also wanted to be able to use
async delegates.
Using my solution
Defining a Delegate is simple as this:
Delegate OnBtnClick;
AsyncDelegate OnNewMail;
To add a new delegate handler to those defined above you have to choose whether you want to use a static/global function or
a member function. To subscribe a delegate you use a syntax similar to C#'s:
class MyClass
{
public:
void Handler1(LPVOID source, DelegateArgs* args)
{
...
}
static void StaticHandler(LPVOID source, DelegateArgs* args)
{
...
}
};
void main()
{
MyClass instance;
Delegate OnBtnClick;
OnBtnClick += NewClassDelegateHandler(MyClass, instance, Handler1);
OnBtnClick += NewDelegateHandler(&MyClass::StaticHandler);
LPVOID source = 0;
DelegateArgs* args = 0;
OnBtnClick.Invoke(source, args);
}
NewClassDelegateHandler
and NewDelegateHandler
are defines that create the appropriate
DelegateHandler
class. It
can be the StaticDelegateHandler
for static functions or ClassDelegateHandler
for member functions.
The async delegate only overrides the Delegate::Invoke
method by creating a thread to invoke the handlers. You can make your
delegate thread safe (AsyncDelegate
already is) by defining a Delegate like this Delegate ThreadSafeDelegate(true);
IMPORTANT: To use my solution you have to enable runtime type information in your project.
XicoLoko is a brazilian developer based in Switzerland.