IDisposable

public class SomeClass: IDisposable
{
    private bool disposed = false;

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

    protected virtual void Dispose(bool disposing)
    {
        if (disposed) return;
        if (disposing)
        {
            // Managed
        }
        // Unmanaged
        disposed = true;
    }

    ~SomeClass()
    {
        Dispose (false);
    }
}