c# - What does x?.y?.z mean?

Question

The draft spec for Pattern Matching in C# contains the following code example:

Type? v = x?.y?.z; 
if (v.HasValue) {
    var value = v.GetValueOrDefault();     
    // code using value 
} 

I understand that Type? indicates that Type is nullable, but assuming x, y, and z are locals, what does x?.y?.z mean?

Answer 1

Be aware that this language feature is only available in C# 6 and later.

It's effectively the equivalent of:

x == null ? null
   : x.y == null ? null
   : x.y.z

In other words, it's a "safe" way to do x.y.z, where any of the properties along the way might be null.

Also related is the null coalescing operator (??), which provides values to substitute for null.