Why do we need events for a callback?

Question

We can call callback methods using delegates. For instance,

public delegate bool ContinueProcessing ();

// later in the code we can write

ContinueProcessing cp = new ContinueProcessing (IsDataAvailable);

cp + = new ContinueProcessing (IsTransactionComplete);

// later in the method code definition

bool IsDataAvailable () {return true; }

bool IsTransactionComplete () {return true; }

cp.Invoke ();

The above call will call two Boolean methods one after another. Why do we need "events"? What is the purpose of "events"?

Answer 1

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Answer 2

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Answer 3

It seems that the keyword "event" is a delegate declaration modifier that allows it to be included in the interface, restricts it to a call inside the class that declares it, provides it with a couple of custom accessors (add and remove) and forces the delegate's signature (when used within .NET platform).