Preemptive Threads and Listboxes Don't Play Nice

[Jon_Ogden]

Actually consider this.

Say you have a URLConnection. You have sent a command to a remote server. The server delays sending the connection for a short bit but then sends the data back. In the mean time you have set the URLConnection to NIL and your WeakAddressOf delegate has now been destroyed. However, the OS framework is in the process of sending the data to your URLConnection object but the delegate method is now NIL and BOOM! Crash goes your app.

See this thread I started back in 2015:

AddressOf vs. WeakAddressOf in AddHandler

In an AddHandler directive, you can use: AddHandler MyControl.SomeEvent, AddressOf SomeMethod or AddHandler MyControl.SomeEvent, WeakAddressOf SomeMethod Using WeakAddressOf means that the handler gets removed as soon as the object is closed or goes out of scope. With AddressOf, you have to be sure to later use a RemoveHandler statement to remove the linkage. So why would you not always want to use WeakAddressOf? Is there ever a time when you would want the event handler relationship to s…