Question

作为一个问题，我需要继续检查文件夹是否在3分钟内创建完毕...最初，我将myVar设置为0，每次计时器运行时，它将在else部分中一直添加到3，然后执行其他操作功能。任何人都可以在这件事上为我提供帮助，因为我不熟悉将数据解析为计时器...

class Program
{
    public static void Main(string[] args)
    {
        int myVar = 0;
        System.Timers.Timer timer = new System.Timers.Timer();
        timer.Interval = 60000; // Currently set to 1 minutes
        timer.Elapsed += (sender, e) => timer_Elapsed(sender, e, myVar);
        timer.Start();
    }

    static void timer_Elapsed(object sender, System.Timers.ElapsedEventArgs e, int myVar)
    {
        DirectoryInfo imagepath = new DirectoryInfo(@"C:\Users");

        DirectoryInfo[] directoryInfo = imagepath.GetDirectories();

        string directoryFolderName = "";
        string subdirectoryFolderName = "";
        string fullPathName = "";


        foreach (DirectoryInfo directory in directoryInfo)
        {
            directoryFolderName = directory.Name;
        }

        if (directoryFolderName.Contains("ABB"))
        {

            fullPathName = imagepath + "\\" + directoryFolderName;
            DirectoryInfo path = new DirectoryInfo(fullPathName);
            DirectoryInfo[] subdirectoryInfo = path.GetDirectories(); ;

            foreach (DirectoryInfo subDirectory in subdirectoryInfo)
              subdirectoryFolderName = subDirectory.Name;


            if (subdirectoryFolderName.Contains("folder"))
            {
                string tempPath = fullPathName + "\\" + "folder";
                mainFunction(path, imagepath);
            }
            else
            {
                Console.WriteLine(fullPathName);
                Console.WriteLine("tif folder not found!!!");
                string msg = "Program failed unexpectedly. Error Msg: folder not found!!!";
                WriteExceptionFile(msg, null);
            }

        }
        else
        {
            Console.WriteLine("Minutes: " + myVar);
            myVar += 1;
        }
}

Answer 1

默认情况下，int是按值传递的，这意味着当您在timer_elapsed方法内部更新变量时，该变量不会反映在该方法之外。

一个简单的解决方案是强制使用ref关键字通过引用传递int：

static void timer_Elapsed(object sender, System.Timers.ElapsedEventArgs e, ref int myVar){ ... }

这是一个简单的演示：https://rextester.com/UOBCK74072

Answer 2

您将myVar作为参数发送。因此，方法的更改不能更改主变量的值。您可以定义myVar静态变量并直接更改其值。也可以使用main方法之外的全局变量。

    static int x = 0;
    static void Main(string[] args)
    {
        Console.WriteLine(x); // before call foo->0
        foo();
        Console.WriteLine(x); // after call foo -> 10
        Console.ReadKey();
    }


    public static void foo()
    {
        x = 10;
    }

Answer 3

使用out关键字从计时器回调中获取更新的值

static void timer_Elapsed(object sender, System.Timers.ElapsedEventArgs e, out int myVar) { ... }

这应该有效。

如何在计时器外部更改临时变量值？

3 个答案: