An event delegate is an example of what kind of design pattern?

Observer Pattern

Explanation:

Observer Pattern comes under behavioural design pattern. It basically  deals with how a class get notified about the state of other object changes which that class is interested in.

Here this uses Events and Delegates for implementing this behaviour. Delegate is a function pointer and Event is the occurrence of some incident. When the event raises what ever the delegate holds it will execute with that event.

for example: parent want to know kid daily status. Here Parent is the observer and kids are the observable collection. Notify Observer is the delegate which holds Updatedailystatus method. when Dailystatuschanged event fired then it will invoke the delegate Notify Observer and  Updatedailystatus method is going to execute which will update the daily status to the parent. This is one example of Observer design pattern