19 May 2019

We learned about the event driven approach and the need of a contract to define a method signature. The .NET message signature type is called delegate and it helps us to store 1 or more methods with the same (exact) signature. Why? so we can Invoke these methods (stored in the delegate) whenever we want to (usually when an event occurs, for example: button-Click). We saw the Action<T> type and the Func<T> type which are actually a delegate wrappers. we understood the loosely couple concept in which we can take two non-related classes and bind them together using the delegate (and unbind them). Finally we saw how to create a delegate method using Lambda expression

More topics covered:

• Publish-Subscriber
• Creating Property of a delegate member
• Using the delegate type as a method parameter
• Using the delegate type as a method return value
• Executing delegate using Invoke and without Invoke
• Delegate can actually store 1 or more methods
• Invoking a delegate execute all of the stored methods

Links:

• • Class code: starting delegate- calculator example
  • Class code: video encoder delegate example
  • Class code: Action<T> syntax
  • Delegate – tutorials teacher link
  • Delegate – MSDN link
  • Lambda Expression – tutorial teacher link
  • Lambda Expression – MSDN link
  • Lesson Summary Video!
  • Home work!