All of us have been exposed to event driven programming of some sort or the other. Only the class that declares the event can fire it better abstraction. If you have not watched parts 106 and 107, i would strongly encourage you to do so before continuing with. In this twopart series well be looking at delegates and events. Delegates are especially used for implementing events and the callback methods. The class containing the event is used to publish the event.
Delegates and events in c journal of object technology. This episode covers how delegates can be used to pass methods as arguments into. A delegate can point to a method, which is having same signature as that of the delegate. The events are declared and raised in a class and associated with the event handlers using delegates within the same class or some other class. Watch this tutorial and your confusion will be gone in 30 minutes.
A collection of registered listeners is notified whenever an event occurs. A delegate is a reference type variable that holds the reference to a method. A delegate is a class that encapsulates a method signature. In the subsequent section of this tutorial, we will be looking at this concept with practical examples. One part is publisher that contains definition of events and delegates and another part is subscriber that accepts the event and provides an event handler. This completes the lesson, which was an introduction to delegates and events. The problem with standard cstyle callback functions is that they represent little more. Some other class that accepts this event is called the subscriber class. You learned how to declare and implement delegates, which provide dynamic runtime method invocation services.
Lets write some code using delegates to understand delegates. Once you learn how to create and manipulate delegate types, you then. You also know how to declare events and use them in a couple different scenarios. In this video we will discuss about raising another custom event from calendarusercontrol. One way is to declare your own event, delegate, and. A delegate is a type safe a function pointer that can reference a method that has the same signature as that of the delegate. Delegates are method wrappers that can be passed to a code which can invoke wrapped method without any compiletime knowledge of which method will be invoked actually. The code used in this article can be downloaded from github.
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