The using statement ensures that IDisposable objects are properly disposed of when they are no longer needed. However, it requires wrapping the code in a block which adds nesting and can make the code harder to read, especially when multiple disposables are involved.

C# 8.0 introduces using declarations which dispose the object at the end of the enclosing scope (typically the method) without requiring an explicit block.

Code

Now

void WriteLog(string message)
{
    using var file = File.OpenWrite("log.txt");
    using var writer = new StreamWriter(file);
    writer.WriteLine(message);
} // both writer and file are disposed here

Before

void WriteLog(string message)
{
    using (var file = File.OpenWrite("log.txt"))
    {
        using (var writer = new StreamWriter(file))
        {
            writer.WriteLine(message);
        }
    }
}

Notes

• The object is disposed at the end of the enclosing scope, typically when the method returns
• Particularly useful when you have multiple disposables that would otherwise require deeply nested blocks
• If you need precise control over when disposal happens, use the traditional using statement with an explicit block

More information

• using declaration
• What's new in C# 8.0