What is the IDisposable pattern?

Question

Accepted Answer

**IDisposable** — deterministic cleanup of unmanaged resources.

**Basic pattern:**
```csharp
public class Resource : IDisposable
{
    private bool _disposed = false;
    private readonly StreamWriter _writer;

public Resource(string path)
    {
        _writer = new StreamWriter(path);
    }

public void Dispose()
    {
        Dispose(true);
        GC.SuppressFinalize(this);
    }

protected virtual void Dispose(bool disposing)
    {
        if (!_disposed)
        {
            if (disposing)
            {
                _writer?.Dispose();
            }
            _disposed = true;
        }
    }

~Resource() => Dispose(false);
}
```

**using statement:**
```csharp
using var resource = new Resource("file.txt");
resource.Write("Hello");
// Dispose called automatically
```

**Resources to dispose:**
- File streams.
- Database connections.
- HTTP clients.
- Socket connections.

C#: What is the IDisposable pattern?