6.0 feature: Null Propogation

Overview

C# 6.0 has some interesting new features. The feature discussed in this post is null propogation. Null propogation allows you to check if a property exists and if it does, execute code. More information can be found here.

Details

Using the ? symbol, we can see if the preceding variable holds a null. If it does, the chain stops and the value returned is null.

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// Before
if (obj != null && obj.children != null) {
  obj.children.Add( new Child() );
}

// In 6.0
if (obj?.children != null) {
  obj.children.Add( new Child() );
}

// 1. Is obj == null? If yes, stop and the chain == null
// 2. Is children == null? If yes, stop and the chain == null