穿线计时器不起作用，为什么？

Question

i have a program which i have a threading timer to update the time coming from the data server. However, i notice the timer run a few times and stop calling afterwards. i try and copy the threading timer code onto a new program and it runs fine, so i know somehow the timer code must have interfere with the rest of the program, but i dont know where, can anyone help me out please?

the program is quite big to post everything here, i try to post all the relevant parts here.

public partial class HistoricalDownload : Form
{
    static int column = 2;
    static int row = 100;

    string timeFmt = "yyyy/MM/dd HH:mm:ss.fff";

    ZenFire.Connection zf;
    ZenFire.Connection.TickEventHandler tick;
    ZenFire.IProduct product = null;

    System.Windows.Forms.TextBox[,] textbox = new System.Windows.Forms.TextBox[column, row];
    DisplayTimer displayTimer = new DisplayTimer();
    memoryStreamClass msc = new memoryStreamClass();
    Dictionary<string, int> dictionarySymbol = new Dictionary<String, int>();
    delegate void StringParameterDelegate(int j, string value);

    public HistoricalDownload(ZenFire.Connection z)
    {
        InitializeComponent();

        int month = 0;
        int year = 0;

        string symbol;
        string exchange;
        string finalSymbol;

        string[] lineSplit;

        zf = z;
        tick = new ZenFire.Connection.TickEventHandler(zf_TickEvent);
        zf.TickEvent += tick;

                //set the array for name and update time 

        for (int k = 0; k < column; k++)
        {
            for (int j = 0; j < row; j++)
            {
                textbox[k, j] = new System.Windows.Forms.TextBox();
                textbox[k, j].Size = new Size(140, 18);
                textbox[k, j].Name = "textbox_" + k + "_" + j;

                if (j >= 50)
                {
                    textbox[k, j].Location = new System.Drawing.Point((k * 140) + 400, ((j - 50) * 18) + 30);
                }
                else
                {
                    textbox[k, j].Location = new System.Drawing.Point((k * 140) + 20, (j * 18) + 30);
                }

                textbox[k, j].Visible = true;
                Controls.Add(textbox[k, j]);
            }
        }

                //load the config file and subscribe the symbol

                    ....

                ///////////////////////////////////////

        System.Threading.TimerCallback displayCallback = new System.Threading.TimerCallback(timeDisplay);
        System.Threading.Timer displayTimerThread = new System.Threading.Timer(displayCallback, displayTimer, 0, 1000);
    }

    public void timeDisplay(object timerObject)
    {
        DisplayTimer t = (DisplayTimer)timerObject;


        for (int j = 0; j < t.row; j++)
        {
            string value = t.outputTime[j].ToString(timeFmt);

            if (value != "0001/01/01 00:00:00.000")
            {
                writeToTextBox(j, value);
            }
        }
    }

    public void writeToTextBox(int j, string value)
    {
        if (InvokeRequired)
        {
            BeginInvoke(new StringParameterDelegate(writeToTextBox), new object[] { j, value });
            return;
        }
        //// Must be on the UI thread if we've got this far
        textbox[1, j].Text = value;
    } 

    void zf_TickEvent(object sender, ZenFire.TickEventArgs e)
    {
        string product = e.Product.ToString();
        int c = dictionarySymbol[product];

        displayTimer.outputTime[c] = e.TimeStamp;

        msc.fillBuffer(string.Format("{0},{1},{2},{3},{4}\r\n",
                        e.TimeStamp.ToString(timeFmt),
                        product,
                        Enum.GetName(typeof(ZenFire.TickType), e.Type),
                        e.Price,
                        e.Volume));
    }

can anyone points out where the interference might be?

Answer 1

If all your're doing in your timer callback is updating the UI, I'd suggest using System.Windows.Forms.Timer instead. You don't have to deal with InvokeRequired / BeginInvoke because that handler runs on the UI thread.

It also appears that you using a local variable for your System.Thread.Timer . That could cause the timer to be finalized after the execution of HistoricalDownload . Which is probably much sooner than you want the timer to stop running. (see first Note at http://msdn.microsoft.com/en-us/library/saba8ksx ) You should put that variable in a field of the parent class--or whatever class will stay "alive" as long as you want the timer to run. I don't think that would be an issue if you used System.Windows.Forms.Timer . But, it's a good idea too keep a field around for something that get's used asynchronously.

Answer 2

The Tick event for the timer may be occurring on a ThreadPool thread (many of the framework timers do this, but since you're using a custom timer ( ZenFire ?), it's impossible to know for sure).

If this is the case, your code is likely not thread safe, and you may be getting an exception within your timer's Tick event. Again, depending on the implementation, the exception may be preventing the timer from functioning correctly after that point.

The particular things to watch for are to not update any UI components from the timer's Tick event - but install, marshal the calls back to the UI thread with Control.Invoke (or Dispatcher.Invoke if you're using WPF). Also, simple things like using your Dictionary<T,U> are not thread safe, so you should synchronize access to these items.