CODEWITHSUNDEEP
c#winformstimer
Alex
Alex

Reputation: 398

C# timers.timer

My application looks like this:

I have an MDI parent form - form1, the form that starts and stops the timer - form 2, and a timerCalls class with all the timer logic.

Form1 code:

TimerCalls timerCalls = new TimerCalls();

public SMS()
{
    InitializeComponent();
    timerCalls.InitializeTimer();
}

Form2 code:

TimerCalls timerCalls = new TimerCalls();

public Form2()
{
    InitializeComponent();
}

private void btnSendOn_Click(object sender, EventArgs e)
{
    timerCalls.sendTimer.Start();
}

private void btnSendOff_Click(object sender, EventArgs e)
{
    timerCalls.sendTimer.Stop();
}

TimerCalls class code:

class TimerCalls
{
    public System.Timers.Timer sendTimer = new System.Timers.Timer();
    public System.Timers.Timer recTimer = new System.Timers.Timer();

    public void InitializeTimer()
    {
        // Send timer
        sendTimer.Elapsed += new ElapsedEventHandler(sendProcessTimerEvent);
        sendTimer.Interval = 3000;
        //rec timer
        recTimer.Elapsed += new ElapsedEventHandler(recProcessTimerEvent);
        recTimer.Interval = 3000;
    }

    private void sendProcessTimerEvent(object sender, EventArgs e)
    {
        MessageBox.Show("Send 3 sec");
    }

    private void recProcessTimerEvent(object sender, EventArgs e)
    {
        MessageBox.Show("Rec 3 sec");
    }
}

This is the problem: I open form2, start the timer, close form2, open it again and try to stop the timer it doesn't stop it. Once I reopen the form2, all I can do is start and stop a new timer, but the previous one is still running. Everything works fine (timer starting and stopping) until I close form2. If the timer was on when I closed the form I can't stop it once I open the form2 again.

How can I fix this?

Upvotes: 0

Views: 728

Answers (4)

Ondrej Tucny
Ondrej Tucny

Reputation: 27962

You are creating multiple instances of TimerCalls — in other words, there is no single time instance, there are many. You can't expect stopping a running timer when you call stop for a different instance.

Create a singleton instance of TimerCalls and that will solve your problem.

Upvotes: 0

Gabriel
Gabriel

Reputation: 1443

After you closed Form2 and reopened it, this is run again:

public System.Timers.Timer sendTimer = new System.Timers.Timer();
public System.Timers.Timer recTimer = new System.Timers.Timer();

public void InitializeTimer()
{
    // Send timer
    sendTimer.Elapsed += new ElapsedEventHandler(sendProcessTimerEvent);
    sendTimer.Interval = 3000;

    // Rec timer
    recTimer.Elapsed += new ElapsedEventHandler(recProcessTimerEvent);
    recTimer.Interval = 3000;
}

Your first timer runs on a different thread and it's not stopped and when you open Form2 for the second time a new timer is initialized so now you have two timers and you can control only the last one.

Upvotes: 0

devrooms
devrooms

Reputation: 3139

Assuming you are closing the form, and then creating a new one then yes, it will create multiple instances of Form2.

The best approach as suggested by others would be to use a singleton pattern for TimerCalls and just get the instance in your Form2.

If this sounds like too much work, simply hide Form2 instead of closing it:

private void Form2_FormClosing(object sender, FormClosingEventArgs e)
{
    if (e.CloseReason != CloseReason.UserClosing)
        return;
    e.Cancel = true;
    Hide();
}

Then just make sure when you click the button to reopen Form2, you just show the previously created one - which will be something like this.

public class Form1 : Form
{
    private Form2 mForm2;

    protected void OpenForm2_Click(object sender, EventArgs e)
    {
       if (mForm2 == null)  
           mForm2 = new Form2();
       mForm2.Show();
    }
}

Upvotes: 2

Edwin de Koning
Edwin de Koning

Reputation: 14387

Each time you open a new Form2 a new timer gets initialized. That will be the one you are starting and stopping. I would advise to either make your Timer class a singleton, or pass a reference of the a single timerCalls instance from Form1 to each new Form 2

Upvotes: 0

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