Event unsubscription and memory in C Sharp (C#) - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to unsubscribe from the event.

C Sharp (C#)

publisher.SomeEvent -= [1];

Drag options to blanks, or click blank then click option'

ASubscribeMethod

BHandlerMethod

CAddHandler

DOnEvent

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different method name than the one used to subscribe.

Trying to unsubscribe with += instead of -=.

You unsubscribe from an event by using the -= operator with the same handler method that was used to subscribe.

2fill in blank

medium

Complete the code to subscribe to the event with a method named OnDataReceived.

C Sharp (C#)

publisher.SomeEvent [1]= OnDataReceived;

Drag options to blanks, or click blank then click option'

A+

B-

C*

D/

Attempts:

3 left

💡 Hint

Common Mistakes

Using -= instead of += to subscribe.

Using * or / operators which are invalid here.

To subscribe to an event, use the += operator with the handler method.

3fill in blank

hard

Fix the error in unsubscribing the event handler named HandleEvent.

C Sharp (C#)

publisher.SomeEvent [1]= HandleEvent;

Drag options to blanks, or click blank then click option'

A+

B*

C-

D/

Attempts:

3 left

💡 Hint

Common Mistakes

Using += instead of -= when unsubscribing.

Using invalid operators like * or /.

Unsubscribing requires the -= operator, not +=.

4fill in blank

hard

Fill both blanks to unsubscribe the event handler and avoid memory leaks.

C Sharp (C#)

publisher.[1] [2]= HandlerMethod;

Drag options to blanks, or click blank then click option'

ASomeEvent

B+

C-

DOtherEvent

Attempts:

3 left

💡 Hint

Common Mistakes

Unsubscribing from the wrong event.

Using += instead of -= to unsubscribe.

You unsubscribe from the correct event using the -= operator to prevent memory leaks.

5fill in blank

hard

Fill all three blanks to subscribe and then unsubscribe the event handler properly.

C Sharp (C#)

publisher.[1] [2]= Handler;
// Later in code
publisher.[1] [3]= Handler;

Drag options to blanks, or click blank then click option'

ASomeEvent

B+

C-

DOtherEvent

Attempts:

3 left

💡 Hint

Common Mistakes

Using different event names for subscribe and unsubscribe.

Using the wrong operator for unsubscribe.

Subscribe with += and unsubscribe with -= on the same event to manage memory correctly.