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…

View original post 407 more words

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