Rhino模拟记录回放语法有趣地使用了using。

using的另一个重要用途是实例化一个模态对话框。

Using frm as new Form1

    Form1.ShowDialog

    ' Do stuff here

End Using

在过去，我经常使用它来处理输入和输出流。您可以很好地嵌套它们，这消除了您通常遇到的许多潜在问题(通过自动调用dispose)。例如:

        using (FileStream fs = new FileStream("c:\file.txt", FileMode.Open))
        {
            using (BufferedStream bs = new BufferedStream(fs))
            {
                using (System.IO.StreamReader sr = new StreamReader(bs))
                {
                    string output = sr.ReadToEnd();
                }
            }
        }

它也可以用于创建作用域，例如:

class LoggerScope:IDisposable {
   static ThreadLocal<LoggerScope> threadScope = 
        new ThreadLocal<LoggerScope>();
   private LoggerScope previous;

   public static LoggerScope Current=> threadScope.Value;

   public bool WithTime{get;}

   public LoggerScope(bool withTime){
       previous = threadScope.Value;
       threadScope.Value = this;
       WithTime=withTime;
   }

   public void Dispose(){
       threadScope.Value = previous;
   }
}


class Program {
   public static void Main(params string[] args){
       new Program().Run();
   }

   public void Run(){
      log("something happend!");
      using(new LoggerScope(false)){
          log("the quick brown fox jumps over the lazy dog!");
          using(new LoggerScope(true)){
              log("nested scope!");
          }
      }
   }

   void log(string message){
      if(LoggerScope.Current!=null){
          Console.WriteLine(message);
          if(LoggerScope.Current.WithTime){
             Console.WriteLine(DateTime.Now);
          }
      }
   }

}

using语句告诉. net一旦不再需要using块中指定的对象，就释放它。

所以你应该使用'using'块来处理那些需要清理的类，比如System。IO类型。

Interestingly, you can also use the using/IDisposable pattern for other interesting things (such as the other point of the way that Rhino Mocks uses it). Basically, you can take advantage of the fact that the compiler will always call .Dispose on the "used" object. If you have something that needs to happen after a certain operation ... something that has a definite start and end ... then you can simply make an IDisposable class that starts the operation in the constructor, and then finishes in the Dispose method.

这允许您使用非常好的使用语法来指示所述操作的显式开始和结束。这也是系统如何。事务处理可以工作。