This code C# is from online source but it was in console application so I modify to work on windows form just for learning on how to use threading.timer , but it doesn't work. Can anyone help me?
I would like the code below to display message to richtextbox while the timer object is not yet destroy so the main thread shouldn't run. When timer object is destroy, the main thread will start and display the last message, "Timer example done."
Can anyone tell me why the timer doesn't execute CheckStatus() because in that method has some message to display, but I don't see the message display at all.. Thanks in advance.
------------------------------------------------------------------------------------------------- - class TimerExampleState
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{
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public int counter = 0;
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public System.Threading.Timer tmr;
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}
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-
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public partial class Form1 : Form
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{
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private string messageString = string.Empty;
-
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public Form1()
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{
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InitializeComponent();
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}
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-
-
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private void button1_Click(object sender, EventArgs e)
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{
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TimerExampleState s = new TimerExampleState();
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//create the delegate that invokes methods for the timer.
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TimerCallback timerDelegate = new TimerCallback(CheckStatus);
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// Create a timer that waits one second, then invokes every second.
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System.Threading.Timer timer = new System.Threading.Timer(timerDelegate, s, 1000, 1000);
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// Keep a handle to the timer, so it can be disposed.
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s.tmr = timer;
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// The main thread does nothing until the timer is disposed.
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while (s.tmr != null)
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Thread.Sleep(0);
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richTextBox1.AppendText("Timer example done.");
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}
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-
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// The following method is called by the timer's delegate.
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private void CheckStatus(Object state)
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{
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TimerExampleState s = (TimerExampleState)state;
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s.counter++;
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messageString = "Checking status: "+ s.counter;
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RunMe();
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//After display message five times, wait for 10 seconds.
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if (s.counter == 5)
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{
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// Shorten the period. Wait 10 seconds to restart the timer.
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(s.tmr).Change(10000, 100);
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messageString = "changed...";
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RunMe();
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}
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if (s.counter == 10)
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{
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messageString = "disposing of timer...";
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s.tmr.Dispose();
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s.tmr = null;
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RunMe();
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}
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}
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private void RunMe()
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{
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//----trying label1
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if (label2.InvokeRequired)
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{
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this.BeginInvoke(new MethodInvoker(RunMe));
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}
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else
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{
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label2.Text = messageString;
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}
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}
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}
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MODERATOR
Thanks, I was looking for the CODE tage too, but I didn't know that code tage is
Plater 7,872
Recognized Expert Expert
I am not sure what Thread.Sleep(0) would do, but it probably means it waits forever. Are you noticing your program just stops working?
Hmmm, when I run this program under console application because that is what originally written on console because I found it on google. According to the console application when I execute, the main thread should not start until the timer get destroy. So the Thread.sleep(0) just put the main thread to sleep, but I dont think it will sleep forever. So the program should display this phrase five time, messageString = "Checking status: "+s.counter , then after five time, it will change to display this phrase, messageString = "changed... " while waiting about 10seconds. When the s.counter reaches 10, the timer object gets destroyed that is when the main thread starts to run and display the last message, richTextBox1.Ap pendText("Timer example done.");
I am not sure what Thread.Sleep(0) would do, but it probably means it waits forever. Are you noticing your program just stops working?
Wait, wait, I was wrong. When I first executed the program, I didn't wait enough times to see the main thread running. When I execute the program, the program doesn't display anything which I'm not sure why it doesn't display anything because I put these three phrases for displaying. -
messageString = "Checking status: "+ s.counter;
-
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messageString = "changed...";
-
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messageString = "disposing of timer...";
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Although none of them display, however the main thread seems to work because it doesn't execute this statement: -
richTextBox1.AppendText("Timer example done.");
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until for quite a while which I approximate the time is almost the same amount of time it takes to get the timer object to destroyed.
Base on the while-condition that i have above: -
while (s1.tmr != null)
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Thread.Sleep(0);
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Those three phrases don't display but when I switch between != to ==, those three phrases display. Hmmm I don't undestand. It seems the timer doesn't get executed because the main thread doesn't run, but when the main thread runs, the timer is executed. But I thought timer is a different thread from the main thread, isn't it?
Plater 7,872
Recognized Expert Expert
Well, I bet if inside that while loop you added Application.DoE vents()
You would see the change.
Well, I bet if inside that while loop you added Application.DoE vents()
You would see the change.
oh my goodness thank you so much. Thank you, thank you. It works just like you said. If you don't mind, can you explain why Application.DoE vent() has to be in there and what for purpose? Hmmm what about console application, why it doesn't need to have Application.DoE vent() and it works?
Plater 7,872
Recognized Expert Expert
Application.DoE vents() tells the program to perform all pending windows messages (generally gui stuff). Your "gui thread" was sitting in that busy loop and never getting a chance to process its events.
Application.DoE vents() tells the program to perform all pending windows messages (generally gui stuff). Your "gui thread" was sitting in that busy loop and never getting a chance to process its events.
Oh I see. So I guess the console doesn't have any gui like form app. is that why it doesn't need DoEvent(), I assume.
Then System.Threadin g.Timer doesn't run on the gui thread?
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