在具有托管和非托管资源的类中

让 finalization 忽略托管资源非常重要。终结器在另一个线程上运行 - 在终结器运行时，托管对象可能不再存在。实现受保护的 Dispose(bool) 方法是一种常见做法，可确保托管资源不会从终结器调用其 Dispose 方法。

public class ManagedAndUnmanagedObject : IDisposable
{
    private SqlConnection sqlConnection = new SqlConnection();
    private UnmanagedHandle unmanagedHandle = Win32.SomeUnmanagedResource();
    private bool disposed;

    public void Dispose()
    {
        Dispose(true); // client called dispose
        GC.SuppressFinalize(this); // tell the GC to not execute the Finalizer
    }

    protected virtual void Dispose(bool disposeManaged)
    {
        if (!disposed)
        {
            if (disposeManaged)
            {
                if (sqlConnection != null)
                {
                    sqlConnection.Dispose();
                }
            }

            unmanagedHandle.Release();

            disposed = true;
        }
    }

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