c# - using 会在 null 上工作吗？

Question

如果资源没有实现 IDisposable，下面的代码可以工作吗？

  T resource = new T();
  using (resource as IDisposable)
  {
     ...
  }

Answer 1

是的。 using 语句检查它是否被赋予 null 并避免尝试调用 Dispose 如果是。

来自 C# 3 规范的第 8.13 节:

A using statement is translated into three parts: acquisition, usage, and disposal. Usage of the resource is implicitly enclosed in a try statement that includes a finally clause. This finally clause disposes of the resource. If a null resource is acquired, then no call to Dispose is made, and no exception is thrown.