using & Dispose in C#

Deterministic cleanup: the file handle closes when the scope ends.

var path = Path.GetTempFileName();

// a using block disposes the writer, flushing it, when the scope ends
using (var writer = new StreamWriter(path))
{
    writer.WriteLine("buffered until disposed");
}

// the shorter using declaration disposes at the end of the method
using var reader = new StreamReader(path);
Console.WriteLine(reader.ReadLine());

How it works

1. The using block disposes the writer at its closing brace, flushing it.
2. A using var declaration disposes at the end of the enclosing method.
3. Anything IDisposable — files, connections, timers — fits this shape.

Keywords and builtins used here

• new
• using
• var

The run, in numbers

Lines

11

Characters to type

348

Tokens

52

Three-star pace

90 tpm

At the three-star pace of 90 tokens a minute, this run takes about 35 seconds.

Type this snippet

Step 3 of 3 in Errors & files, step 27 of 29 in Language basics.

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