Question

I’m attempting to implement the MSDN example (http://msdn.microsoft.com/en-us/library/swx5easy.aspx) for Thread.Timers in my own code.

I want to be able to cancel the timer when a certain user action is performed, however I can not dispose the timer, I suspect this is because I’m calling a method from another class so I need to adjust; but I don’t know where.

Other than this, the timer works fine. Can anyone see why my timer will not cancel when btnconfigOpenConfig is called?

FYI I’m converting what was a worker process to a timed event.

public partial class Xservt : Window
        {

            internal class TimerStateObjClass
            {
                public int SomeValue;
                public System.Threading.Timer SqlUpdateFromTwitterTimerReference;
                public bool TimerCanceled;
            }


internal void SomeMethod(){


                    TimerStateObjClass stateObj = new TimerStateObjClass();
                    stateObj.TimerCanceled = false;
                    stateObj.SomeValue = 100;
                    System.Threading.TimerCallback timerDelegate =
                        new System.Threading.TimerCallback(twit.hometimelineclass._sqlUpdateFromTwitterWorker_DoWork);

                    var sqlUpdateFromTwitterTimer = new Timer(timerDelegate, stateObj, 0,20000);
                    stateObj.SqlUpdateFromTwitterTimerReference = sqlUpdateFromTwitterTimer;

    }
}


//action to perform which disposes the timer
private void btnconfigOpenConfig(object sender, RoutedEventArgs e)
            {

                TimerStateObjClass timerState = new TimerStateObjClass();
                timerState.TimerCanceled = true;
    }


//Actions the timer is calling, in another class
internal static void _sqlUpdateFromTwitterWorker_DoWork(object StateObj)
            {

                Xservt.TimerStateObjClass state = (Xservt.TimerStateObjClass) StateObj;

                if(state.TimerCanceled)
                {
                    state.SqlUpdateFromTwitterTimerReference.Dispose();

                }

    //some work
    }

Answer 1

As Hans pointed out in the comments, you need to keep a reference to TimerStateObjClass you originally created. You can then use that to set TimerCanceled.

public partial class Xservt : Window
{

    internal class TimerStateObjClass
    {
        public int SomeValue;
        public System.Threading.Timer SqlUpdateFromTwitterTimerReference;
        public bool TimerCanceled;
    }

    TimerStateObjClass stateObj;  //THIS IS THE ORIGINAL STATE OBJ
    internal void SomeMethod()
    {
        stateObj = new TimerStateObjClass();
        stateObj.TimerCanceled = false;
        stateObj.SomeValue = 100;
        System.Threading.TimerCallback timerDelegate = new System.Threading.TimerCallback(twit.hometimelineclass._sqlUpdateFromTwitterWorker_DoWork);

        var sqlUpdateFromTwitterTimer = new Timer(timerDelegate, stateObj, 0, 20000);
        stateObj.SqlUpdateFromTwitterTimerReference = sqlUpdateFromTwitterTimer;
    }

    //action to perform which disposes the timer
    private void btnconfigOpenConfig(object sender, RoutedEventArgs e)
    {
        //HERE WE CAN GET AT THE ORIGINAL STATE OBJ
        stateObj.TimerCanceled = true;
    }
}
    //Actions the timer is calling, in another class
    internal static void _sqlUpdateFromTwitterWorker_DoWork(object StateObj)
    {
        Xservt.TimerStateObjClass state = (Xservt.TimerStateObjClass)StateObj;

        if (state.TimerCanceled)
        {
            state.SqlUpdateFromTwitterTimerReference.Dispose();
        }

        //some work
    }