Using Timer only once

Question

I want to use a timer only once, at 1 second after the initialization of my main form. I thought the following would have a message box saying "Hello World" just once, but actually a new message box says "Hello World" every one second.

Why so? I had put t.Stop() in the tick event. Also, do I need to dispose the timer somehow to avoid memory leakage?

        Timer t = new Timer();
        t.Interval = 1000;                
        t.Tick += delegate(System.Object o, System.EventArgs e)
                        { MessageBox.Show("Hello World"); t.Stop(); };

        t.Start();

Please help and show if there is a better way of doing this? Thanks.

Yuriy Faktorovich · Accepted Answer · 2010-05-15 18:09:42Z

9

Replace MessageBox.Show("Hello World"); t.Stop(); with t.Stop();MessageBox.Show("Hello World");. Because you're not pressing OK in time, the timer has already ticked again and you never reached the stop code.

answered May 15, 2010 at 18:09

Yuriy Faktorovich

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5 Comments

zaidwaqi Over a year ago

Ok, that works. Thanks. But what's the logic? Why the order matters?

Yuriy Faktorovich Over a year ago

@zaidwaqi: The thread goes into MessageBox.Show method, and doesn't leave until you press OK. But you don't press OK fast enough, and it has already opened a new MessageBox.

zaidwaqi Over a year ago

Oh :) What about disposing the timer? Is it needed since the timer will not be used anymore?

Sebastian Over a year ago

@zaidwaqi, well you could call t.Dispose() after t.Stop()

Yuriy Faktorovich Over a year ago

@SebastianGodelet As long as he doesn't need it again, he should probably be doing that anyway.

Robb · Accepted Answer · 2010-05-15 18:11:25Z

2

Put t.Stop(); before the MessageBox.Show("Hellow World");

answered May 15, 2010 at 18:11

Robb

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Comments

user232548 · Accepted Answer · 2017-06-22 10:36:19Z

1

You can achieve this also with System.Timers.Timer and setting AutoReset to false. I was looking into which timer to use and prefer this one as it does not require the separate stop command.

using System;
using System.IO;
using System.Timers;

System.Timers.Timer t = new System.Timers.Timer() {
    Interval = 1000,
    AutoReset = false
};

t.Elapsed  += delegate(System.Object o, System.Timers.ElapsedEventArgs e)
    { Console.WriteLine("Hell");}; 
t.Start();

answered Jun 22, 2017 at 10:36

user232548

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