Question

class WakeUP
{
    [DllImport("kernel32.dll")]
    public static extern SafeWaitHandle CreateWaitableTimer(IntPtr lpTimerAttributes, 
                                                              bool bManualReset,
                                                            string lpTimerName);

    [DllImport("kernel32.dll", SetLastError = true)]
    [return: MarshalAs(UnmanagedType.Bool)]
    public static extern bool SetWaitableTimer(SafeWaitHandle hTimer, 
                                                [In] ref long pDueTime, 
                                                          int lPeriod,
                                                       IntPtr pfnCompletionRoutine, 
                                                       IntPtr lpArgToCompletionRoutine, 
                                                         bool fResume);

    public event EventHandler Woken;

    private BackgroundWorker bgWorker = new BackgroundWorker();

    public WakeUP()
    {
        bgWorker.DoWork += new DoWorkEventHandler(bgWorker_DoWork);
        bgWorker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bgWorker_RunWorkerCompleted);
    }

    public void SetWakeUpTime(DateTime time, String tName)
    {
        // Create a 7-tuple. 
        var wutargs = new Tuple<string, string>(time.ToFileTime().ToString(), tName.ToString()); 
        bgWorker.RunWorkerAsync(wutargs);
    }

    void bgWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
    {
        if (Woken != null)
        {
            Woken(this, new EventArgs());
        }
    }

    private void bgWorker_DoWork(object sender, DoWorkEventArgs e) 
    {
        var thetuple = e.Argument;
        long wakeuptime = (long)thetuple.Item1;

        using (SafeWaitHandle handle = CreateWaitableTimer(IntPtr.Zero, true, "Timer"))
        {
            //if (SetWaitableTimer(handle, ref "12:00 AM", 0, IntPtr.Zero, IntPtr.Zero, true))
            //{
                //using (EventWaitHandle wh = new EventWaitHandle(false, EventResetMode.AutoReset))
                //{
                    //wh.SafeWaitHandle = handle;
                    //wh.WaitOne();
                //}
            //}
            //else
            //{
                //throw new Win32Exception(Marshal.GetLastWin32Error());
            //}
        }
    }

Visual Studio告诉我：

        long wakeuptime = (long)thetuple.Item1;

错误1'对象'不包含'Item1'的定义，也没有扩展方法'Item1'接受类型'object'的第一个参数（你是否缺少using指令或汇编引用？）C ：\ Users \ esepich \ Documents \ Visual Studio 2013 \ Projects \ SepysAlarmV1ecs \ SepysAlarmV1 \ WakeUP.cs 57 46 SepysAlarmV1

我应该如何访问元组的元素？

感谢您发帖...

Answer 1

参数可以是任何类型。它作为object传递，因此将其转换回原始类型：

var thetuple = (Tuple<string, string>)e.Argument;

你也会在下一行得到编译错误：

long wakeuptime = (long)thetuple.Item1;

考虑使用Convert.ToInt64或Int64.TryParse。

C＃Tuple。不包含Item1的定义

1 个答案: