Clean event handler invocation with C# 6

Jon Skeet's coding blog

The problem

Invoking event handlers in C# has always been a bit of a pain, because an event with no subscribers is usually represented as a null reference. This leads to code like this:

It’s important to use the handler local variable, as if instead you access the field twice, it’s possible that the last subscriber will unsubscribe between the check and the invocation:

Now this can be simplified slightly using an extension method:

Then in each event, you can write a single line:

However, this means having a different extension method for each delegate type. It’s not too bad if you’re using EventHandler but it’s still not ideal.

C# 6 to the rescue!

The null-conditional operator (?.) in C# 6 isn’t just for properties. It can also be used for method calls. The compiler does the right thing (evaluating the expression only once) so you can do…

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