Even And Deligate

[Peter]

I have the following code which uses Events and Deligate, I need to have a
timer in a library and update UI everytime the event fires.

but I am getting the following error in Reading method and the following
statement this.label1.Tex t = val.ToString(); :

Cross-thread operation not valid: Control 'label1' accessed from a thread
other than the thread it was created on.

How can I fix this problem?


using System;
using System.Collecti ons.Generic;
using System.Componen tModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows. Forms;
using LabExampleLib;

namespace LabExample
{
public partial class Form1 : Form
{
TimerLib tl = new TimerLib();
int i = 0;

public Form1()
{
InitializeCompo nent();
tl.Reading += new TimerLib.Calcul ate(Reading);
}

void Reading(double val)
{
i++;
this.label1.Tex t = val.ToString();

}

private void button1_Click(o bject sender, EventArgs e)
{
tl.Start();
}
}
}


using System;
using System.Collecti ons.Generic;
using System.Text;
using System.Threadin g;
using System.Timers;

namespace LabExampleLib
{
public class TimerLib
{
public delegate void Calculate(doubl e val);
public event Calculate Reading;

private double i = 0;
System.Timers.T imer aTimer;

public TimerLib()
{
aTimer = new System.Timers.T imer();
aTimer.Elapsed += new ElapsedEventHan dler(OnTimedEve nt);
}

private void OnTimedEvent(ob ject source, ElapsedEventArg s e)
{
i++;
OnReading(i);
}

public void Start()
{
aTimer.Interval = 1000;
aTimer.Enabled = true;

}

protected void OnReading(doubl e val)
{
if (Reading != null)
Reading(val);
}
}
}


Thank You

Peter

[DrewCE]

Re: Even And Deligate

This, it seems, is a right of passage for beginning .Net users.

You are only allowed to update the UI from the UI thread. See the following
link and code excerpt from said link....

http://msdn.microsoft.com/en-us/library/ms171728(VS.80).aspx

// This method demonstrates a pattern for making thread-safe
// calls on a Windows Forms control.
//
// If the calling thread is different from the thread that
// created the TextBox control, this method creates a
// SetTextCallback and calls itself asynchronously using the
// Invoke method.
//
// If the calling thread is the same as the thread that created
// the TextBox control, the Text property is set directly.

private void SetText(string text)
{
// InvokeRequired required compares the thread ID of the
// calling thread to the thread ID of the creating thread.
// If these threads are different, it returns true.
if (this.textBox1. InvokeRequired)
{
SetTextCallback d = new SetTextCallback (SetText);
this.Invoke(d, new object[] { text });
}
else
{
this.textBox1.T ext = text;
}
}
Good luck,-Drew"Peter" <czupet@nospam. nospamwrote in message
news:eiCKmkTHJH A.4884@TK2MSFTN GP03.phx.gbl...

>I have the following code which uses Events and Deligate, I need to have a
>timer in a library and update UI everytime the event fires.
>
but I am getting the following error in Reading method and the following
statement this.label1.Tex t = val.ToString(); :
>
Cross-thread operation not valid: Control 'label1' accessed from a thread
other than the thread it was created on.
>
How can I fix this problem?
>
>
using System;
using System.Collecti ons.Generic;
using System.Componen tModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows. Forms;
using LabExampleLib;
>
namespace LabExample
{
public partial class Form1 : Form
{
TimerLib tl = new TimerLib();
int i = 0;
>
public Form1()
{
InitializeCompo nent();
tl.Reading += new TimerLib.Calcul ate(Reading);
}
>
void Reading(double val)
{
i++;
this.label1.Tex t = val.ToString();
>
}
>
private void button1_Click(o bject sender, EventArgs e)
{
tl.Start();
}
}
}
>
>
using System;
using System.Collecti ons.Generic;
using System.Text;
using System.Threadin g;
using System.Timers;
>
namespace LabExampleLib
{
public class TimerLib
{
public delegate void Calculate(doubl e val);
public event Calculate Reading;
>
private double i = 0;
System.Timers.T imer aTimer;
>
public TimerLib()
{
aTimer = new System.Timers.T imer();
aTimer.Elapsed += new ElapsedEventHan dler(OnTimedEve nt);
}
>
private void OnTimedEvent(ob ject source, ElapsedEventArg s e)
{
i++;
OnReading(i);
}
>
public void Start()
{
aTimer.Interval = 1000;
aTimer.Enabled = true;
>
}
>
protected void OnReading(doubl e val)
{
if (Reading != null)
Reading(val);
}
}
}
>
>
Thank You
>
Peter
>
>

[Peter]

Re: Even And Deligate


"DrewCE" <moc.sgodniahc@ werd - backwardswrote in message
news:24D8C930-10D7-47DF-99CE-AA89AE70471C@mi crosoft.com...

This, it seems, is a right of passage for beginning .Net users.
>
You are only allowed to update the UI from the UI thread. See the
following link and code excerpt from said link....
>

http://msdn.microsoft.com/en-us/library/ms171728(VS.80).aspx

// This method demonstrates a pattern for making thread-safe
// calls on a Windows Forms control.
//
// If the calling thread is different from the thread that
// created the TextBox control, this method creates a
// SetTextCallback and calls itself asynchronously using the
// Invoke method.
//
// If the calling thread is the same as the thread that created
// the TextBox control, the Text property is set directly.
>
private void SetText(string text)
{
// InvokeRequired required compares the thread ID of the
// calling thread to the thread ID of the creating thread.
// If these threads are different, it returns true.
if (this.textBox1. InvokeRequired)
{
SetTextCallback d = new SetTextCallback (SetText);
this.Invoke(d, new object[] { text });
}
else
{
this.textBox1.T ext = text;
}
}
Good luck,-Drew"Peter" <czupet@nospam. nospamwrote in message
news:eiCKmkTHJH A.4884@TK2MSFTN GP03.phx.gbl...

>>I have the following code which uses Events and Deligate, I need to have a
>>timer in a library and update UI everytime the event fires.
>>
>but I am getting the following error in Reading method and the following
>statement this.label1.Tex t = val.ToString(); :
>>
>Cross-thread operation not valid: Control 'label1' accessed from a thread
>other than the thread it was created on.
>>
>How can I fix this problem?
>>
>>
>using System;
>using System.Collecti ons.Generic;
>using System.Componen tModel;
>using System.Data;
>using System.Drawing;
>using System.Text;
>using System.Windows. Forms;
>using LabExampleLib;
>>
>namespace LabExample
>{
> public partial class Form1 : Form
> {
> TimerLib tl = new TimerLib();
> int i = 0;
>>
> public Form1()
> {
> InitializeCompo nent();
> tl.Reading += new TimerLib.Calcul ate(Reading);
> }
>>
> void Reading(double val)
> {
> i++;
> this.label1.Tex t = val.ToString();
>>
> }
>>
> private void button1_Click(o bject sender, EventArgs e)
> {
> tl.Start();
> }
> }
>}
>>
>>
>using System;
>using System.Collecti ons.Generic;
>using System.Text;
>using System.Threadin g;
>using System.Timers;
>>
>namespace LabExampleLib
>{
> public class TimerLib
> {
> public delegate void Calculate(doubl e val);
> public event Calculate Reading;
>>
> private double i = 0;
> System.Timers.T imer aTimer;
>>
> public TimerLib()
> {
> aTimer = new System.Timers.T imer();
> aTimer.Elapsed += new ElapsedEventHan dler(OnTimedEve nt);
> }
>>
> private void OnTimedEvent(ob ject source, ElapsedEventArg s e)
> {
> i++;
> OnReading(i);
> }
>>
> public void Start()
> {
> aTimer.Interval = 1000;
> aTimer.Enabled = true;
>>
> }
>>
> protected void OnReading(doubl e val)
> {
> if (Reading != null)
> Reading(val);
> }
> }
>}
>>
>>
>Thank You
>>
>Peter
>>
>>

>

Thanks the problem is solved.