C# 8.0 Features: Nullable Reference Types Explained

Nullable reference types are the biggest C# 8.0 feature. They help eliminate null reference exceptions at compile time. Here’s how they work.

Enabling Nullable

<PropertyGroup>
  <Nullable>enable</Nullable>
</PropertyGroup>

The New Syntax

// Non-nullable (default with feature enabled)
string name = "John";  // Cannot be null

// Nullable 
string? nickname = null;  // Explicitly nullable

// Must check before using
if (nickname != null)
{
    Console.WriteLine(nickname.Length);  // Safe
}

Null Forgiving Operator

// When you know better than the compiler
string? maybeNull = GetValue();
string definitelyNotNull = maybeNull!;  // Trust me

Benefits

• Compiler warnings for potential null dereferences
• Documentation of intent in method signatures
• Catches bugs before runtime

References

• Nullable Reference Types