Develop Reference

Repeat ping every 30 seconds

I created a Windows Forms application to ping a list of Ip addresses, then i used a Timer to repeat the ping every 30 seconds. This is the code i used:
private System.Timers.Timer timer;
public Form1()
{
InitializeComponent();
timer = new System.Timers.Timer();
timer.Interval = 30000;
timer.Enabled = true;
timer.Elapsed += button1_Click;
}
private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
pingResults.Clear();
ipAddress.Add("10.100.1.1");
ipAddress.Add("10.100.1.2");
ipAddress.Add("10.100.1.3");
ipAddress.Add("10.100.1.4");
ipAddress.Add("10.100.1.5");
ipAddress.Add("10.100.1.100");
for (int i = 1; i < 7; i++)
{
pictureBoxList.Add((PictureBox)Controls.Find("pictureBox" + i, true)[0]);
}
Parallel.For(0, ipAddress.Count(), (i, loopState) =>
{
Ping ping = new Ping();
PingReply pingReply = ping.Send(ipAddress[i].ToString());
this.BeginInvoke((Action)delegate()
{
pictureBoxList[i].BackColor = (pingReply.Status == IPStatus.Success) ? Color.Green : Color.Red;
});
});
}
private void button1_Click(object sender,ElapsedEventArgs e )
{
backgroundWorker1.RunWorkerAsync();
}
But i got this error message:
Error 1 No overload for 'button1_Click' matches delegate 'System.EventHandler'
I tried a lot of examples but i didn't get how to use the Timer. what is the problem here or is there any other way to repeat the Ping?

Please, note that Button.Clicked and Timer.Elapsed have different signatures; you, probably, want
public Form1()
{
InitializeComponent();
timer = new System.Timers.Timer();
timer.Interval = 30000;
timer.Enabled = true;
timer.Elapsed += timer_Elapsed; // not button1_Click
}
...
private void timer_Elapsed(object sender, ElapsedEventArgs e)
{
backgroundWorker1.RunWorkerAsync();
}
private void button1_Click(object sender, EventArgs e)
{
backgroundWorker1.RunWorkerAsync();
}
Or you can get rid of timer_Elapsed at all with a help of lambda function:
public Form1()
{
InitializeComponent();
timer = new System.Timers.Timer();
timer.Interval = 30000;
timer.Enabled = true;
timer.Elapsed += (s, e) => {backgroundWorker1.RunWorkerAsync();};
}
...
private void button1_Click(object sender, EventArgs e)
{
backgroundWorker1.RunWorkerAsync();
}

Your idea with the timer is a perfect idea. Anyhow now you try to activate the timer with a button which will not work properly.
Try this example from the microsoft documentation
https://learn.microsoft.com/en-us/dotnet/api/system.timers.timer?view=netframework-4.8

Looking on the definition of System.EventHandler (at https://learn.microsoft.com/en-us/dotnet/api/system.eventhandler?view=netframework-4.8), we see that it's:
[System.Runtime.InteropServices.ComVisible(true)]
[System.Serializable]
public delegate void EventHandler(object sender, EventArgs e);
It's a delegate, which takes one parameter of type System.EventArgs and one of type object. Looking on your code:
private void button1_Click(object sender, ElapsedEventArgs e)
We see that your event handler receives an object and an ElapsedEventArgs, which is a subclass of EventArgs. But you can't use it, since the compiler expect EventArgs (the opposite, superclass instead of subclass, of course allowed). This is the meaning of the error message:
Error 1 No overload for 'button1_Click' matches delegate 'System.EventHandler'
I (the compiler) expected a method matches the signature of System.EventHandler, but didn't got.

Form timer doesn't start

So I just started learning C# and using forms. I have been able to create a digital clock and tinker with this and that, but now I'm trying to make a basic UI for a derpy game and my timer doesn't work.
First - what I'm trying to accomplish: A simple decrementing timer from 60 seconds (*clock style (mm:ss)).
Second, here's what I have:
public partial class Form1 : Form
{
private int counter = 60;
public Form1()
{
InitializeComponent();
label1.Text = TimeSpan.FromMinutes(1).ToString("m\\:ss");
}
private void pictureBox2_Click(object sender, EventArgs e)
{
}
private void timer1_Tick(object sender, EventArgs e)
{
counter--;
if (counter == 0)
{
timer1.Stop();
label1.Text = counter.ToString();
MessageBox.Show("Time's Up!!");
}
}
private void label1_Click(object sender, EventArgs e)
{
var startTime = DateTime.Now;
var counter = (TimeSpan.FromMinutes(1)).ToString("m\\:ss");
timer1 = new Timer();
timer1.Tick += new EventHandler(timer1_Tick);
timer1.Interval = 1000;
timer1.Start();
label1.Text = counter.ToString();
}
}
Appreciate the feedback and knowledge!

From the codes that I see, your timer is working but you are not updating it in each count, you are updating when the timer finishes -
private void timer1_Tick(object sender, EventArgs e)
{
counter--;
if (counter == 0)
{
timer1.Stop();
label1.Text = counter.ToString(); // *** Look here
MessageBox.Show("Time's Up!!");
}
}
You should update the timer in each tick, so take the update label code out of the if block -
private void timer1_Tick(object sender, EventArgs e)
{
counter--;
label1.Text = counter.ToString(); // should work
if (counter == 0)
{
timer1.Stop();
MessageBox.Show("Time's Up!!");
}
}
and also reset the counter in each cycle -
private void label1_Click(object sender, EventArgs e)
{
var startTime = DateTime.Now;
var counter = (TimeSpan.FromMinutes(1)).ToString("m\\:ss");
timer1 = new Timer();
timer1.Tick += new EventHandler(timer1_Tick);
timer1.Interval = 1000;
timer1.Start();
label1.Text = counter.ToString();
this.counter = 60
}
NOTE: I am really not sure if this code will throw any access
violation error, due to updating the UI in a different thread or not.
If so, then you have to use async/await or events/delegates to
update UI.
Let me know, if this throws error, then I will give you the async/await version.

This works fine for me. I would give progress updates as the time is countdown to show that it is working. For example, if you did this in label, you could do something like the following:
private void timer1_Tick(object sender, EventArgs e)
{
counter--;
label1.Text = counter.ToString();
if (counter == 0)
{
timer1.Stop();
MessageBox.Show("Time's Up!!");
}
}
Notice that the label1.Text = counter.ToString(); line has been moved before the counter == 0 check, so that it is able to provide feedback for all counter values.
As well, you may accidentally launch several timer1 instances if you do not keep track of how many you spawn using new Timer(). There are various ways to do this, but you could simply check whether timer1 already exists and counter == 0 before creating a new instance. You could perform this check as a guard clause (ie. return if either of those conditions are matched).
private void label1_Click(object sender, EventArgs e)
{
var startTime = DateTime.Now;
if (timer1 == null || (timer1 != null && counter == 0)) return;
counter = (TimeSpan.FromMinutes(1)).ToString("m\\:ss");
timer1 = new Timer();
timer1.Tick += new EventHandler(timer1_Tick);
timer1.Interval = 1000;
timer1.Start();
label1.Text = counter.ToString();
}
If you want this countdown to start automatically, you can put this directly into the constructor, or put it into another method and call it from the constructor like so:
public Form1()
{
InitializeComponent();
StartCountdown();
}
private void StartCountdown()
{
var startTime = DateTime.Now;
/* the rest of your original label1_Click code goes here ... */
}

Timer using label

So, this seems to be a common question but I can't seem to figure out a way to do this. I have a C# Form application that goes out to an imap client and processes the emails. I want to have a timer formatted like "08:45" (for 8 minutes and 45 seconds) displayed on the form to let the user know how long it has been since they clicked the button to start the process.
I want the timer to stop once my process ends obviously.
private void btn_ImportEmail_Click(object sender, EventArgs e)
{
this.timer = new System.Timers.Timer();
this.lblTimer = new System.Windows.Forms.Label();
((System.ComponentModel.ISupportInitialize) (this.timer)).BeginInit();
this.timer.Elapsed += new System.Timers.ElapsedEventHandler(this.OnTimerElapsed);
//connect to email and download messages...
this.timer.Enabled = true;
this.timer.SynchronizingObject = this;
timer.Interval = 1000;
timer.Start();
for (int I = 0 ; I <= messages.count() - 1; I++)
{
//process emails
}
timer.EndInit();
}
private void timer1_Tick(object sender, EventArgs e)
{
lblTimer.Text = DateTime.Now.ToString("mm:ss");
}
private void OnTimerElapsed(object sender, System.Timers.ElapsedEventArgs e)
{
lblTimer.Text = DateTime.Now.ToString("mm:ss");
// lblTimer.Text = string.Format("{0:mm:ss}", DateTime.Now);
}

The following SO Q/A might answer your question...
Display the running time of part of a program in a label
I would recommend changing the format to your needs.

The first thing that I see is that you are using DateTime.Now which will give you the current minutes and seconds, not elapsed minutes and seconds. The second thing and the main thing is that since you are processing your emails in your main UI's thread you are preventing your label from being updated, you would be better off looking at using a background worker instead.
Edit based on Idle_Mind's comment added DateTime Object instead of counter.
public partial class Form1 : Form
{
BackgroundWorker bgw = new BackgroundWorker();
Timer timer = new Timer();
DateTime startTime;
public Form1()
{
InitializeComponent();
timer.Interval = 1000;
timer.Tick += timer_Tick;
bgw.DoWork += bgw_DoWork;
bgw.RunWorkerCompleted+=bgw_RunWorkerCompleted;
}
void timer_Tick(object sender, EventArgs e)
{
label1.Text =((TimeSpan)DateTime.Now.Subtract(startTime)).ToString("mm\\:ss");
}
void bgw_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
timer.Stop();
}
void bgw_DoWork(object sender, DoWorkEventArgs e)
{
for (int I = 0 ; I <= messages.count() - 1; I++)
{
//process emails
}
}
private void button1_Click(object sender, EventArgs e)
{
bgw.RunWorkerAsync();
startTime = DateTime.Now;
timer.Start();
}
}

Getting time until next event

I have a sync timer in my app that fires up a function at a given time... now I want to know how much time is left until the next call to that function.
This is my call to the timer:
var syncTime = time.activitylog;
double time = TimeSpan.Parse(syncTime).TotalMilliseconds;
System.Timers.Timer myTimer = new System.Timers.Timer();
myTimer.Elapsed += new ElapsedEventHandler(DisplayTimeEvent);
myTimer.Interval = time;
myTimer.Start();
How do I get the time until next call?
Thanks

You can use another timer, and set the Interval of that the value that you want,exactly a part time of the Interval of original timer.
Then start them Simultaneously,I mean at the same time.
UPDATE :
Maybe this code describes my solution better :
public Form1()
{
InitializeComponent();
}
System.Windows.Forms.Timer trOriginal = new System.Windows.Forms.Timer();
System.Windows.Forms.Timer trRemain = new System.Windows.Forms.Timer();
double remain = 0;
private void button1_Click(object sender, EventArgs e)
{
trOriginal.Interval = 1000;
trRemain.Interval = 1;
trOriginal.Tick += new EventHandler(trOriginal_Tick);
trRemain.Tick += new EventHandler(trRemain_Tick);
trOriginal.Start();
trRemain.Start();
}
void trRemain_Tick(object sender, EventArgs e)
{
remain -= trRemain.Interval;
Console.WriteLine("remain MS to next event : " + remain);
}
void trOriginal_Tick(object sender, EventArgs e)
{
remain = trOriginal.Interval;
}

You can use a System.Diagnostics.Stopwatch to keep track of how much time has passed already and restart the Stopwatch with every tick of your Timer.
Stopwatch watch = new Stopwatch();
private void DisplayTimeEvent(object sender, EventArgs e)
{
watch.Restart();
// Whatever is supposed to happen, when the timer ticks
}
Now whenever you want to know how much time is left until the event is fired next, you can do this:
long timeLeft = myTimer.Interval - watch.ElapsedMilliseconds;

moving a button using a timer

I have four buttons that are called "ship1,ship2" etc.
I want them to move to the right side of the form (at the same speed and starting at the same time), and every time I click in one "ship", all the ships should stop.
I know that I need to use a timer (I have the code written that uses threading, but it gives me troubles when stopping the ships.) I don't know how to use timers.
I tried to read the timer info in MDSN but I didn't understand it.
So u can help me?
HERES the code using threading.
I don't want to use it. I need to use a TIMER! (I posted it here because it doesnt give me to post without any code
private bool flag = false;
Thread thr;
public Form1()
{
InitializeComponent();
}
private void button2_Click(object sender, EventArgs e)
{
flag = false;
thr = new Thread(Go);
thr.Start();
}
private delegate void moveBd(Button btn);
void moveButton(Button btn)
{
int x = btn.Location.X;
int y = btn.Location.Y;
btn.Location = new Point(x + 1, y);
}
private void Go()
{
while (((ship1.Location.X + ship1.Size.Width) < this.Size.Width)&&(flag==false))
{
Invoke(new moveBd(moveButton), ship1);
Thread.Sleep(10);
}
MessageBox.Show("U LOOSE");
}
private void button1_Click(object sender, EventArgs e)
{
flag = true;
}

Have you googled Windows.Forms.Timer?
You can start a timer via:
Timer timer = new Timer();
timer.Interval = 1000; //one second
timer.Elapsed += new System.Timers.ElapsedEventHandler(timer_Elapsed);
timer.Enabled = true;
timer.Start();
You'll need an event handler to handle the Elapsed event which is where you'll put the code to handle moving the 'Button':
private void timer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
{
MoveButton();
}