I want to have a section of my code start a timer once it's called, and I want this timer to keep running until I quit the whole program. My problem is, each time I call OnSomethingHappens() , the Elapsed events aggregate (despite my effort with -= ) and the timer starts firing one extra time (or at least this is what I think is happening). I have also tried defining the timer within the class, to no avail. Here's the related part of my code:
public override void OnSomethingHappens()
{
Timer aTimer= new System.Timers.Timer();
aTimer.Elapsed -= (sender, e) => DoSomethingElse(sender, e);
aTimer.Stop();
aTimer.Close();
aTimer.Elapsed += (sender, e) => DoSomethingElse(sender, e);
aTimer.Interval = 1000;
aTimer.AutoReset = true; // I want the timer to keep working, but only fire once each time
Console.WriteLine("Enabling Timer aTimer");
aTimer.Start();
}
I cannot use static (not sure how that would help but I saw timers being defined as static in many sources) because this class has many instances, and I want them to have separate timers.
Thank you.
Start your timer without the AutoReset and restart it at the end of the DoSomethingElse.
aTimer.AutoReset = false;
aTimer.Start();
DoSomethingElse(..)
{
// do stuff here
aTimer.Start();
}
if each instance of this class uses his own timer , so static is no needed.
private Timer _aTimer;
public void OnSomethingHappens()
{
if (_aTimer != null)
{
_aTimer.Enabled = true; // start timer
return;
}
_aTimer = new System.Timers.Timer();
_aTimer.Elapsed += DoSomethingElse;
_aTimer.Interval = 1000; // every 1 second
_aTimer.Enabled = true; // start timer
}
private void DoSomethingElse(object sender, ElapsedEventArgs e)
{
_aTimer.Enabled = false; // stop timer
// do w/e you want
}
First thing you should really only create once instance of the timer, and hook up one event listener. With your current code, a new timer is being created, with an event listener, every time the method is called. Instead make the timer a class variable, and hook up the event listener in the constructor.
You can start the timer in the OnSomethingHappens, but what do you want to happen on subsequent calls to the method? Should the timer restart, or just continue?
You would probably also want to make the class IDisposable, or at least provide a Stop method to stop the timer when the application closes.
public class MyClass : MyBaseClass, IDisposable
{
private Timer _timer;
private volatile bool _isStopped = true;
public MyClass()
{
_timer = new Timer();
_timer.Interval = 1000;
_timer.Elapsed = OnTimerElapsed;
}
public void Stop()
{
_isStopped = true;
_timer.Stop();
}
public void Dispose()
{
if (_timer != null)
{
Stop();
_timer = null;
}
}
protected override void OnSomethingHappens()
{
if (_timer.Enabled)
{
// Restart or do nothing if timer is already running?
}
else
{
_isStopped = false;
_timer.Start();
}
}
private void OnTimerElapsed(object sender, EventArgs a)
{
if (_isStopped)
{
// If the Stop method was called after the Elapsed event was raised, don't start a long running operation
return;
}
}
}
Related
This is my implementation of a Win Form app that has a countdown timer:
readonly DateTime myThreshold;
public Form1()
{
InitializeComponent();
myThreshold = Utils.GetDate();
Timer timer = new Timer();
timer.Interval = 1000; //1 second
timer.Tick += new EventHandler(t_Tick);
timer.Start();
//Threshold check - this only fires once insted of each second
if (DateTime.Now.CompareTo(myThreshold) > 0)
{
// STOP THE TIMER
timer.Stop();
}
else
{
//do other stuff
}
}
void t_Tick(object sender, EventArgs e)
{
TimeSpan timeSpan = myThreshold.Subtract(DateTime.Now);
this.labelTimer.Text = timeSpan.ToString("d' Countdown - 'hh':'mm':'ss''");
}
The wanted behavior is to stop the timer and the tick function when the threshold is reached.
This now does not happens because the check is only executed once since it is placed in the Form1 initialization.
Does exist a way to add this check in a way to immediately stop the Timer once a condition has been meet?
If we define timer as a class field (so it can be accessed from all methods in the class), then we can just add the check to the Tick event itself, and stop the timer from there:
private Timer timer = new Timer();
void t_Tick(object sender, EventArgs e)
{
// Stop the timer if we've reached the threshold
if (DateTime.Now > myThreshold) timer.Stop();
TimeSpan timeSpan = myThreshold.Subtract(DateTime.Now);
this.labelTimer.Text = timeSpan.ToString("d' Countdown - 'hh':'mm':'ss''");
}
I have console application am using as demo to an App, it prints "hello", based on the timespan its expected to alert the user. when its not yet the timespan, i want to delay the app from printing hello and resume when its time.
public static async void timeCounter(int delae)
{
//This is suppose to cause a delay but it instead initiate the
//TimerOperation_Tick method.
await Task.Delay(delae);
// timer countdown
System.Timers.Timer timer = new System.Timers.Timer();
timer.Interval = 1000; // 1 second
timer.Elapsed += new ElapsedEventHandler(TimerOperation_Tick);
timer.Start();
if (obj.SubmissionCheck == true)
{
timer.Stop();
}
}
/// the event subscriber
private static void TimerOperation_Tick(object e, ElapsedEventArgs args)
{
if (timeFrame != 0)
{
Console.WriteLine("hi" + timeFrame);
timeFrame --;
if (timeFrame < 1)
{
obj.SubmissionCheck = true;
nt.Remove(obj);
startNotification();
}
}
}
Try setting timer.Enabled = false; This will prevent the timer ticks from occurring.
Background: I have a timer that I am using to keep track of how long it has been since the serialPort DataReceived event has been fired. I am creating my own solution to this instead of using the built in timeout event because I am getting a continuous stream of data, instead of sending a query and getting one response.
The Problem:
In the DataReceived handler I have a statement to stop the timer so that is doesn't elapse. the problem is that a lot of the time it still executes the Elapsed handler afterword.
I have read that is is possible to use SynchronizingObject to solve this problem but I am not sure how to accomplish that.
Here is my code: I tried to cut out everything that I didn't think was relevant.
private System.Timers.Timer timeOut;
private System.Timers.Timer updateTimer;
public void start()
{
thread1 = new Thread(() => record());
thread1.Start();
}
public void requestStop()
{
this.stop = true;
this.WaitEventTest.Set();
}
private void record()
{
timeOut = new System.Timers.Timer(500); //** .5 Sec
updateTimer = new System.Timers.Timer(500); //** .5 Sec
timeOut.Elapsed += TimeOut_Elapsed;
updateTimer.Elapsed += updateTimer_Elapsed;
updateTimer.AutoReset = true;
comport.Open();
comport.DiscardInBuffer();
comport.Write(COMMAND_CONTINUOUSMODE + "\r");
stopwatch.Reset();
stopwatch.Start();
recordingStartTrigger(); //** Fire Recording Started Event
timeOut.Start();
updateTimer.Start();
this.waitHandleTest.WaitOne(); //** wait for test to end
timeOut.Stop();
updateTimer.Stop();
comport.Write(COMMAND_COMMANDMODE + Environment.NewLine);
comport.DiscardInBuffer();
comport.Close();
recordingStopTrigger(status); //** Fire Recording Stopped Event
stopwatch.Stop();
}
//***********************************************************************************
//** Events Handlers
private void comDataReceived_Handler(object sender, SerialDataReceivedEventArgs e)
{
double force = -100000;
string temp = "-100000";
//timeOut.SynchronizingObject.Invoke(new Action(()=> {timeOut.Stop();}), new object[] {sender, e});
timeOut.Stop();
//** I removed my action code here, keep things simple.
timeOut.Start();
}
private void TimeOut_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
{
timeOut.Stop();
updateTimer.Stop();
//** fire delegate that GUI will be listening to, to update graph.
if (eventComTimeOut != null && this.stop == false)
{
if (eventComTimeOut(this, new eventArgsComTimeOut(comport.PortName, "READ")))
{
//retry = true;
comport.Write(COMMAND_CONTINUOUSMODE + "\r");
updateTimer.Start();
timeOut.Start();
}
else
{
this.stop = true;
//retry = false;
this.WaitEventTest.Set();
status = eventArgsStopped.Status.failed;
}
}
}
void updateTimer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
{
//** fire delegate that GUI will be listening to, to update graph.
List<Reading> temp = new List<Reading>(report.Readings_Force);
eventNewData(this, new eventArgsNewData(temp));
}
This is well known behavior. System.Timers.Timer internally uses ThreadPool for execution. Runtime will queue the Timer in threadpool. It would have already queued before you have called Stop method. It will fire at the elapsed time.
To avoid this happening set Timer.AutoReset to false and start the timer back in the elapsed handler if you need one. Setting AutoReset false makes timer to fire only once, so in order to get timer fired on interval manually start timer again.
yourTimer.AutoReset = false;
private void Timer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
{
try
{
// add your logic here
}
finally
{
yourTimer.Enabled = true;// or yourTimer.Start();
}
}
I did a pause in timer with this code. for me that works.
Private cTimer As New System.Timers.Timer
Private Sub inittimer()
cTimer.AutoReset = True
cTimer.Interval = 1000
AddHandler cTimer.Elapsed, AddressOf cTimerTick
cTimer.Enabled = True
End Sub
Private Sub cTimerTick()
If cTimer.AutoReset = True Then
'do your code if not paused by autoreset false
End If
End Sub
Had the same problem and after some trying ended up with timer object to null and replace the timer variable it with a new timer object fixed the issue. I know its heavy of resources. But it solves the problem.
What would happen with the code below if Execute() takes, say, 3000ms to finish, but is being called every 1000ms due to the timer interval?
Timer _timer = new Timer();
private void setupTimer()
{
_timer.Tick += new EventHandler(pollingTimeElapsed);
_timer.Interval = 1000;
_timer.Enabled = true;
_timer.Start();
}
private void pollingTimeElapsed(object sender, EventArgs e)
{
Execute();
}
EDIT: I am using System.Windows.Forms.Timer, since System.Timers.Timer doesn't have .Tick
I'm assuming you are using the System.Timers.Timer class.
Since AutoReset has the default value (which is True), the Elapsed event will be fired for each time 1000ms has elapsed.
If you want to fire the event only one time, set AutoReset to False.
If you do not want to fire the event while your execute-code is running, do the following:
Timer _timer = new Timer();
private void setupTimer() {
_timer.Tick += new EventHandler(pollingTimeElapsed);
_timer.Interval = 1000;
_timer.Enabled = true;
_timer.Start();
}
private void pollingTimeElapsed(object sender, EventArgs e) {
try {
_timer.Stop()
Execute();
} finally {
_timer.Start()
}
}
I have been working on a program that has 3 classes of which 2 of the classes have timers that repeat at different intervals and once one "cycle" of the timer is done it raises an event with a string as return. The 3rd class subscribes to the events from the other two timer classes and prints them to screen. it works great!
But my issue is that it is printing them separately. Lets say that the first timer class runs and then raises "hello" every 2 minutes and the other class "dog" every second and every time an event is raised it prints the raised event to console. I would want it to instead print "hellodog" every second and store the value of the first timer(hello) in a private field or something so it still prints to screen even if the timer(the slower 2 minute timer) hasn't been fired. and when the 2 minute timer fires it updates the value to whatever the new one is and that new value get printed to screen until it fires again.
If it is confusing I will gladly clarify. its kind of hard to explain.
namespace Final
{
public class Output
{
public static void Main()
{
var timer1 = new FormWithTimer();
var timer2 = new FormWithTimer2();
timer1.NewStringAvailable += new EventHandler<BaseClassThatCanRaiseEvent.StringEventArgs>(timer1_NewStringAvailable);
timer2.NewStringAvailable += new EventHandler<BaseClassThatCanRaiseEvent.StringEventArgs>(timer2_NewStringAvailable);
Console.ReadLine();
}
static void timer1_NewStringAvailable(object sender, BaseClassThatCanRaiseEvent.StringEventArgs e)
{
var theString = e.Value;
//To something with 'theString' that came from timer 1
Console.WriteLine(theString);
}
static void timer2_NewStringAvailable(object sender, BaseClassThatCanRaiseEvent.StringEventArgs e)
{
var theString2 = e.Value;
//To something with 'theString2' that came from timer 2
Console.WriteLine(theString2);
}
}
public abstract class BaseClassThatCanRaiseEvent
{
public class StringEventArgs : EventArgs
{
public StringEventArgs(string value)
{
Value = value;
}
public string Value { get; private set; }
}
//The event itself that people can subscribe to
public event EventHandler<StringEventArgs> NewStringAvailable;
protected void RaiseEvent(string value)
{
var e = NewStringAvailable;
if (e != null)
e(this, new StringEventArgs(value));
}
}
public partial class FormWithTimer : BaseClassThatCanRaiseEvent
{
Timer timer = new Timer();
public FormWithTimer()
{
timer = new System.Timers.Timer(200000);
timer.Elapsed += new ElapsedEventHandler(timer_Tick); // Everytime timer ticks, timer_Tick will be called
timer.Interval = (200000); // Timer will tick evert 10 seconds
timer.Enabled = true; // Enable the timer
timer.Start(); // Start the timer
}
void timer_Tick(object sender, EventArgs e)
{
...
RaiseEvent(gml.ToString());
}
}
public partial class FormWithTimer2 : BaseClassThatCanRaiseEvent
{
Timer timer = new Timer();
public FormWithTimer2()
{
timer = new System.Timers.Timer(1000);
timer.Elapsed += new ElapsedEventHandler(timer_Tick2); // Everytime timer ticks, timer_Tick will be called
timer.Interval = (1000); // Timer will tick evert 10 seconds
timer.Enabled = true; // Enable the timer
timer.Start(); // Start the timer
}
void timer_Tick2(object sender, EventArgs e)
{
...
RaiseEvent(aida.ToString());
}
}
}
You can use the same event handler for both timers. And construct the output by identifying the senders. (Didn't test the code for syntax errors.)
private static string timer1Value = string.Empty;
private static string timer2Value = string.Empty;
private static FormWithTimer timer1;
private static FormWithTimer2 timer2;
public static void Main()
{
timer1 = new FormWithTimer();
timer2 = new FormWithTimer2();
timer1.NewStringAvailable += new EventHandler<BaseClassThatCanRaiseEvent.StringEventArgs>(timer1_NewStringAvailable);
timer2.NewStringAvailable += new EventHandler<BaseClassThatCanRaiseEvent.StringEventArgs>(timer1_NewStringAvailable);
Console.ReadLine();
}
static void timer1_NewStringAvailable(object sender, BaseClassThatCanRaiseEvent.StringEventArgs e)
{
if (sender == timer1)
{
timer1Value = e.Value.ToString();
}
else if (sender == timer2)
{
timer2Value = e.Value.ToString();
}
if (timer1Value != String.Empty && timer2Value != String.Empty)
{
Console.WriteLine(timer1Value + timer2Value);
// Do the string concatenation as you want.
}
Correct me if I misunderstand the question, but it sounds like you want to coordinate your response to the two timer events (print "hellodog").
It seems to me that the easiest way to do this is to just use a single timer, and have the timer's event handler count the number of times the handler has been invoked to decide whether to take the once-per-second action, or also take the once-per-two-minutes action.
Since the slow timer is an exact multiple of your fast timer, you would set just one timer that triggers every second, and also do the 2-minute action every 120 invocations of the 1 second timer (120 seconds = 2 minutes).
I think I understand what you want and that is to synchronize the output of both timers. I am afraid there is no way to do it other than to slog through it. Set up a bunch of Boolean variables that track whether each event fired and whether the synchronized message was sent to the output.
This should do what you want.
public static void Main()
{
var timer1 = new FormWithTimer();
var timer2 = new FormWithTimer2();
var value1 = "";
var value2 = "";
Action writeValues = () => Console.WriteLine(value1 + value2);
timer1.NewStringAvailable += (s, e) =>
{
value1 = e.Value;
writeValues();
};
timer2.NewStringAvailable += (s, e) =>
{
value2 = e.Value;
writeValues();
};
Console.ReadLine();
}
Let me know if this is right. Cheers.
The second (quicker) timer should be the only one to print.
The first (slower) timer should only update a string which the second timer will use.
In the 'Output' class (you can put it before Main):
string string1;
and then:
static void timer1_NewStringAvailable(object sender, BaseClassThatCanRaiseEvent.StringEventArgs e)
{
string1 = e.Value;
}
static void timer2_NewStringAvailable(object sender, BaseClassThatCanRaiseEvent.StringEventArgs e)
{
var theString2 = e.Value;
//To something with 'theString2' that came from timer 2
Console.WriteLine(string1 + theString2);
}