“使用”语句中的 C# 匿名对象可靠吗？

Question

想象一下这个片段：

using System;



public class Report {
    static int Level=0;

    public static void WriteLine(string Message) {
        Console.WriteLine("{0}{1}",new String(' ',4*Level),Message);
    }

    public class Indent:IDisposable {
        public Indent()            { Report.WriteLine("{"); ++Level; }
        void IDisposable.Dispose() { --Level; Report.WriteLine("}"); }
    }
}



class Program {
    static void Main() {
        Report.WriteLine("Started");
        Report.WriteLine("Calling submethod");
        using(new Report.Indent()) {
            Report.WriteLine("Submethod started");
            using(new Report.Indent()) Report.WriteLine("Subsub, maybe?");
            Report.WriteLine("Submethod reporting everything is fine");
            Report.WriteLine("Submethod finished");
        }
        Report.WriteLine("Finished");
    }
}

产生结果：

Started
Calling submethod
{
    Submethod started
    {
        Subsub, maybe?
    }
    Submethod reporting everything is fine
    Submethod finished
}
Finished

在里面，我使用using(new Report.Indent())而不是坚持我找到的唯一记录版本，即using(Report.Indent r=new Report.Indent()).

然而，在我的简短版本中，我能确定Dispose()每次都会在那些未命名的 Indent 对象上调用吗？

聚苯乙烯

// btw, I used word "anonymous" in the title, but I'm not sure that's what new objects that aren't assigned to any named variable should be called

Answer 1

是的，using确保即使是“匿名对象”也总是被处理掉。

在内部，using存储在局部变量中输入块时使用的任何值。这个存储的值在退出块时被释放。