Question

Is it possible to somehow shorten this statement?

if (obj != null)
    obj.SomeMethod();

because I happen to write this a lot and it gets pretty annoying. The only thing I can think of is to implement Null Object pattern, but that’s not what I can do every time and it’s certainly not a solution to shorten syntax.

And similar problem with events, where

public event Func<string> MyEvent;

and then invoke

if (MyEvent != null)
    MyEvent.Invoke();

Answer 1

From C# 6 onwards, you can just use:

MyEvent?.Invoke();

or:

obj?.SomeMethod();

The ?. is the null-propagating operator, and will cause the .Invoke() to be short-circuited when the operand is null. The operand is only accessed once, so there is no risk of the “value changes between check and invoke” problem.

===

Prior to C# 6, no: there is no null-safe magic, with one exception; extension methods – for example:

public static void SafeInvoke(this Action action) {
    if(action != null) action();
}

now this is valid:

Action act = null;
act.SafeInvoke(); // does nothing
act = delegate {Console.WriteLine("hi");}
act.SafeInvoke(); // writes "hi"

In the case of events, this has the advantage of also removing the race-condition, i.e. you don’t need a temporary variable. So normally you’d need:

var handler = SomeEvent;
if(handler != null) handler(this, EventArgs.Empty);

but with:

public static void SafeInvoke(this EventHandler handler, object sender) {
    if(handler != null) handler(sender, EventArgs.Empty);
}

we can use simply:

SomeEvent.SafeInvoke(this); // no race condition, no null risk