C# Feature - Using declarations

Overview

Using declarations shorten deterministic disposal by letting the scope, not a nested block, define the disposal boundary.

Introduced In

C# 8.0 (2019)

Before

using (var stream = File.OpenRead(path))
{
  Process(stream);
}

After

using var stream = File.OpenRead(path);
Process(stream);

Gotchas & Best Practices

• Disposal happens at the end of the containing scope, not right after the next statement.
• Use the classic using statement when you need a tighter disposal block.