event accessor example - null?

[emma_middlebrook]

Hi

In MSDN, in the Using Events (C# Programming Guide), declaring event
accessors part it uses the following ...

But the lock will fail at the first call to add because
TestEventHandlers is null.

Any ideas how to fix this up? I can't just initialize the event with
something because it doesn't really make sense ...

private TestEventDelegate TestEventHandlers;

public event TestEventDelegate TestEvent
{
add
{
lock (TestEventHandlers)
{
TestEventHandlers += value;
}
}
remove
{
lock (TestEventHandlers)
{
TestEventHandlers -= value;
}
}
}

Cheers

Emma

 

[Jon Skeet [C# MVP]]

In MSDN, in the Using Events (C# Programming Guide), declaring event
accessors part it uses the following ...

But the lock will fail at the first call to add because
TestEventHandlers is null.

Any ideas how to fix this up? I can't just initialize the event with
something because it doesn't really make sense ...

You should use a separate variable for the lock.
See http://www.pobox.com/~skeet/csharp/threads/lockchoice.shtml

 

[emma_middlebrook]

You should use a separate variable for the lock.
See http://www.pobox.com/~skeet/csharp/threads/lockchoice.shtml

Ah, of course, thanks for that Jon!

Wow, good set of articles you've written - going to read through the
multithreading one.

Cheers

Emma.