Thread won't start...

**Jon Skeet [C# MVP]** · Jan 30 '06, 09:55 AM

Re: Thread won't start...

taylorj...@gmai l.com wrote:[color=blue]
> I am completely baffled. I am writting a daemon application for my
> work to save me some time. The application works fine at my home but
> won't work right here at work. Basically I have a MainForm what has a
> Start/Stop button that starts and stops the processing thread.[/color]

Could you post a short but complete program that demonstrates the
problem?
You shouldn't need much to show it. See
http://www.pobox.com/~skeet/csharp/complete.html for what I mean by
that.

Note that your bStopSignal variable *must* be volatile (or a
synchronized property) for your code to be thread-safe.
See http://www.pobox.com/~skeet/csharp/t...latility.shtml for
more on that.

Also note that you shouldn't use UI components created in one thread on
another thread. See
http://www.pobox.com/~skeet/csharp/t...winforms.shtml for more than
that. (My guess is that your web browser is a UI component.) That
probably isn't the problem here (if you aren't seeing the message box
from the start of the other thread) but it may well bite you as soon as
you get past this initial problem.

Jon

**taylorjonl** · Jan 30 '06, 11:05 AM

Re: Thread won't start...

using System;
using System.Drawing;
using System.Collecti ons;
using System.Componen tModel;
using System.Windows. Forms;
using System.Data;
using System.IO;
using System.Threadin g;

namespace Issue
{
/// <summary>
/// Summary description for Form1.
/// </summary>
public class MainForm : System.Windows. Forms.Form
{
private System.Windows. Forms.Label MemberLabel;
internal System.Windows. Forms.MainMenu MainMenu;
private System.Windows. Forms.MenuItem menuItem1;
private System.Windows. Forms.MenuItem menuItem2;
private System.Windows. Forms.MenuItem menuItem3;
private System.Windows. Forms.MenuItem menuItem4;
private System.Windows. Forms.TextBox MemberTextBox;
private System.Windows. Forms.Button AddButton;
private System.Windows. Forms.ListBox QueuedListBox;
private System.Windows. Forms.StatusBar statusBar1;
private System.Windows. Forms.NotifyIco n NotifyIcon;
private System.Componen tModel.IContain er components;
private System.Windows. Forms.Button StartButton;
private System.Windows. Forms.Button StopButton;
private System.Windows. Forms.GroupBox IssueCloseGroup ;
private System.Windows. Forms.CheckBox Issue12CheckBox ;
private System.Windows. Forms.CheckBox Issue28CheckBox ;
private System.Windows. Forms.CheckBox Issue29CheckBox ;
private System.Windows. Forms.MenuItem ImportMenuItem;
private System.Windows. Forms.MenuItem menuItem6;
private System.Windows. Forms.MenuItem ExitMenuItem;
private System.Windows. Forms.OpenFileD ialog ImportFileDialo g;

// member processing variables
private Thread pProcessingThre ad;
private bool bStopSignal;
private Queue pMemberQueue;

public MainForm()
{
//
// Required for Windows Form Designer support
//
InitializeCompo nent();

//
// TODO: Add any constructor code after InitializeCompo nent call
//

// setup member processing variables
bStopSignal = true;
pMemberQueue = new Queue();
}

/// <summary>
/// Clean up any resources being used.
/// </summary>
protected override void Dispose( bool disposing )
{
if( disposing )
{
if (components != null)
{
components.Disp ose();
}
}
base.Dispose( disposing );
}

/// <summary>
/// </summary>
private void SyncLists()
{
QueuedListBox.I tems.Clear();
object[] contents = new object[pMemberQueue.Co unt];
pMemberQueue.Co pyTo( contents, 0 );
QueuedListBox.I tems.AddRange( contents );
}

/// <summary>
/// </summary>
private void ThreadProc()
{
MessageBox.Show ( "Please browse to the issue viewer base URL to
start" );

string member = null;
while( !bStopSignal )
{
// get the next member
lock( pMemberQueue )
{
if( pMemberQueue.Co unt < 1 )
{
Thread.Sleep( 100 );
continue;
}
member = (string)pMember Queue.Dequeue() ;

// sync the QueuedListBox and pMemberQueue contencts
SyncLists();

///////////////////////////////////////////////////////////
// Busines logic was here
///////////////////////////////////////////////////////////
}
}
}

#region Windows Form Designer generated code
/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeCompo nent()
{
this.components = new System.Componen tModel.Containe r();
System.Resource s.ResourceManag er resources = new
System.Resource s.ResourceManag er(typeof(MainF orm));
this.MemberLabe l = new System.Windows. Forms.Label();
this.MainMenu = new System.Windows. Forms.MainMenu( );
this.menuItem1 = new System.Windows. Forms.MenuItem( );
this.menuItem2 = new System.Windows. Forms.MenuItem( );
this.menuItem3 = new System.Windows. Forms.MenuItem( );
this.menuItem4 = new System.Windows. Forms.MenuItem( );
this.MemberText Box = new System.Windows. Forms.TextBox() ;
this.AddButton = new System.Windows. Forms.Button();
this.QueuedList Box = new System.Windows. Forms.ListBox() ;
this.statusBar1 = new System.Windows. Forms.StatusBar ();
this.NotifyIcon = new
System.Windows. Forms.NotifyIco n(this.componen ts);
this.StartButto n = new System.Windows. Forms.Button();
this.StopButton = new System.Windows. Forms.Button();
this.IssueClose Group = new System.Windows. Forms.GroupBox( );
this.Issue29Che ckBox = new System.Windows. Forms.CheckBox( );
this.Issue28Che ckBox = new System.Windows. Forms.CheckBox( );
this.Issue12Che ckBox = new System.Windows. Forms.CheckBox( );
this.ImportMenu Item = new System.Windows. Forms.MenuItem( );
this.menuItem6 = new System.Windows. Forms.MenuItem( );
this.ExitMenuIt em = new System.Windows. Forms.MenuItem( );
this.ImportFile Dialog = new System.Windows. Forms.OpenFileD ialog();
this.IssueClose Group.SuspendLa yout();
this.SuspendLay out();
//
// MemberLabel
//
this.MemberLabe l.Location = new System.Drawing. Point(8, 8);
this.MemberLabe l.Name = "MemberLabe l";
this.MemberLabe l.Size = new System.Drawing. Size(48, 23);
this.MemberLabe l.TabIndex = 0;
this.MemberLabe l.Text = "Member";
//
// MainMenu
//
this.MainMenu.M enuItems.AddRan ge(new System.Windows. Forms.MenuItem[]
{
this.menuItem1,
this.menuItem2,
this.menuItem3,
this.menuItem4} );
//
// menuItem1
//
this.menuItem1. Index = 0;
this.menuItem1. MenuItems.AddRa nge(new
System.Windows. Forms.MenuItem[] {
this.ImportMenu Item,
this.menuItem6,
this.ExitMenuIt em});
this.menuItem1. Text = "&File";
//
// menuItem2
//
this.menuItem2. Index = 1;
this.menuItem2. Text = "&Edit";
//
// menuItem3
//
this.menuItem3. Index = 2;
this.menuItem3. Text = "&View";
//
// menuItem4
//
this.menuItem4. Index = 3;
this.menuItem4. Text = "&Help";
//
// MemberTextBox
//
this.MemberText Box.Location = new System.Drawing. Point(56, 8);
this.MemberText Box.Name = "MemberTextBox" ;
this.MemberText Box.Size = new System.Drawing. Size(168, 20);
this.MemberText Box.TabIndex = 1;
this.MemberText Box.Text = "";
//
// AddButton
//
this.AddButton. Location = new System.Drawing. Point(232, 8);
this.AddButton. Name = "AddButton" ;
this.AddButton. Size = new System.Drawing. Size(50, 23);
this.AddButton. TabIndex = 2;
this.AddButton. Text = "Add";
this.AddButton. Click += new
System.EventHan dler(this.AddBu tton_Click);
//
// QueuedListBox
//
this.QueuedList Box.Location = new System.Drawing. Point(8, 40);
this.QueuedList Box.Name = "QueuedListBox" ;
this.QueuedList Box.Size = new System.Drawing. Size(272, 108);
this.QueuedList Box.TabIndex = 3;
//
// statusBar1
//
this.statusBar1 .Location = new System.Drawing. Point(0, 245);
this.statusBar1 .Name = "statusBar1 ";
this.statusBar1 .ShowPanels = true;
this.statusBar1 .Size = new System.Drawing. Size(288, 22);
this.statusBar1 .TabIndex = 4;
this.statusBar1 .Text = "statusBar1 ";
//
// NotifyIcon
//
// this.NotifyIcon .Icon =
((System.Drawin g.Icon)(resourc es.GetObject("N otifyIcon.Icon" )));
this.NotifyIcon .Text = "Issue Closing Daemon";
this.NotifyIcon .Visible = true;
this.NotifyIcon .DoubleClick += new
System.EventHan dler(this.Notif yIcon_DoubleCli ck);
//
// StartButton
//
this.StartButto n.Location = new System.Drawing. Point(120, 160);
this.StartButto n.Name = "StartButto n";
this.StartButto n.Size = new System.Drawing. Size(160, 32);
this.StartButto n.TabIndex = 5;
this.StartButto n.Text = "Start";
this.StartButto n.Click += new
System.EventHan dler(this.Start Button_Click);
//
// StopButton
//
this.StopButton .Enabled = false;
this.StopButton .Location = new System.Drawing. Point(120, 208);
this.StopButton .Name = "StopButton ";
this.StopButton .Size = new System.Drawing. Size(160, 32);
this.StopButton .TabIndex = 6;
this.StopButton .Text = "Stop";
this.StopButton .Click += new
System.EventHan dler(this.StopB utton_Click);
//
// IssueCloseGroup
//
this.IssueClose Group.Controls. Add(this.Issue2 9CheckBox);
this.IssueClose Group.Controls. Add(this.Issue2 8CheckBox);
this.IssueClose Group.Controls. Add(this.Issue1 2CheckBox);
this.IssueClose Group.Location = new System.Drawing. Point(8, 152);
this.IssueClose Group.Name = "IssueCloseGrou p";
this.IssueClose Group.Size = new System.Drawing. Size(104, 88);
this.IssueClose Group.TabIndex = 7;
this.IssueClose Group.TabStop = false;
this.IssueClose Group.Text = "Issues to close";
//
// Issue29CheckBox
//
this.Issue29Che ckBox.Checked = true;
this.Issue29Che ckBox.CheckStat e =
System.Windows. Forms.CheckStat e.Checked;
this.Issue29Che ckBox.Location = new System.Drawing. Point(8, 64);
this.Issue29Che ckBox.Name = "Issue29CheckBo x";
this.Issue29Che ckBox.Size = new System.Drawing. Size(72, 15);
this.Issue29Che ckBox.TabIndex = 2;
this.Issue29Che ckBox.Text = "Issue 29";
//
// Issue28CheckBox
//
this.Issue28Che ckBox.Checked = true;
this.Issue28Che ckBox.CheckStat e =
System.Windows. Forms.CheckStat e.Checked;
this.Issue28Che ckBox.Location = new System.Drawing. Point(8, 40);
this.Issue28Che ckBox.Name = "Issue28CheckBo x";
this.Issue28Che ckBox.Size = new System.Drawing. Size(72, 15);
this.Issue28Che ckBox.TabIndex = 1;
this.Issue28Che ckBox.Text = "Issue 28";
//
// Issue12CheckBox
//
this.Issue12Che ckBox.Location = new System.Drawing. Point(8, 16);
this.Issue12Che ckBox.Name = "Issue12CheckBo x";
this.Issue12Che ckBox.Size = new System.Drawing. Size(72, 15);
this.Issue12Che ckBox.TabIndex = 0;
this.Issue12Che ckBox.Text = "Issue 12";
//
// ImportMenuItem
//
this.ImportMenu Item.Index = 0;
this.ImportMenu Item.Text = "&Import File";
this.ImportMenu Item.Click += new
System.EventHan dler(this.Impor tMenuItem_Click );
//
// menuItem6
//
this.menuItem6. Index = 1;
this.menuItem6. Text = "-";
//
// ExitMenuItem
//
this.ExitMenuIt em.Index = 2;
this.ExitMenuIt em.Text = "&Exit";
this.ExitMenuIt em.Click += new
System.EventHan dler(this.ExitM enuItem_Click);
//
// MainForm
//
this.AutoScaleB aseSize = new System.Drawing. Size(5, 13);
this.ClientSize = new System.Drawing. Size(288, 267);
this.Controls.A dd(this.IssueCl oseGroup);
this.Controls.A dd(this.StopBut ton);
this.Controls.A dd(this.StartBu tton);
this.Controls.A dd(this.statusB ar1);
this.Controls.A dd(this.QueuedL istBox);
this.Controls.A dd(this.AddButt on);
this.Controls.A dd(this.MemberT extBox);
this.Controls.A dd(this.MemberL abel);
this.FormBorder Style =
System.Windows. Forms.FormBorde rStyle.FixedDia log;
this.MaximizeBo x = false;
this.Menu = this.MainMenu;
this.Name = "MainForm";
this.Text = "Issue Closing Daemon";
this.Resize += new System.EventHan dler(this.MainF orm_Resize);
this.Closing += new
System.Componen tModel.CancelEv entHandler(this .MainForm_Closi ng);
this.IssueClose Group.ResumeLay out(false);
this.ResumeLayo ut(false);

}
#endregion

/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main()
{
// start application
Application.Run ( new MainForm() );
}

#region Form Event Handlers

/// <summary>
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void AddButton_Click (object sender, System.EventArg s e)
{
// add member to queue and clear text box
pMemberQueue.En queue( MemberTextBox.T ext ); MemberTextBox.C lear();

// update the QueuedListBox
SyncLists();
}

/// <summary>
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void MainForm_Closin g(object sender,
System.Componen tModel.CancelEv entArgs e)
{
// stop the processing thread.
bStopSignal = true;
if( pProcessingThre ad != null )
pProcessingThre ad.Join();
}

/// <summary>
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void MainForm_Resize (object sender, System.EventArg s e)
{
// hide the form if minimize requested
if( FormWindowState .Minimized == this.WindowStat e )
this.Hide();
}

/// <summary>
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void NotifyIcon_Doub leClick(object sender, System.EventArg s
e)
{
// show MainForm and set to appropriate state
this.Show(); this.WindowStat e = FormWindowState .Normal;
}

/// <summary>
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void StartButton_Cli ck(object sender, System.EventArg s e)
{
if( bStopSignal )
{
// disable controls that aren't valid when running
StartButton.Ena bled = false;
Issue12CheckBox .Enabled = false;
Issue28CheckBox .Enabled = false;
Issue29CheckBox .Enabled = false;

// enable controls that are valid when running
StopButton.Enab led = true;

// start the processing thread
bStopSignal = false;
MessageBox.Show ( "Starting Processing Thread" );
(pProcessingThr ead = new Thread( new ThreadStart( ThreadProc )
)).Start();
}
}

/// <summary>
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void StopButton_Clic k(object sender, System.EventArg s e)
{
// enable controls that are valid when stopped
StartButton.Ena bled = true;
Issue12CheckBox .Enabled = true;
Issue28CheckBox .Enabled = true;
Issue29CheckBox .Enabled = true;

// disable controls that aren't valid when stopped
StopButton.Enab led = false;

// stop the processing thread
bStopSignal = true;
if( pProcessingThre ad != null )
{
MessageBox.Show ( "Stopping Processing Thread" );
pProcessingThre ad.Join();
pProcessingThre ad = null;
}
}

private void ExitMenuItem_Cl ick(object sender, System.EventArg s e)
{

}

private void ImportMenuItem_ Click(object sender, System.EventArg s e)
{
if( ImportFileDialo g.ShowDialog() == DialogResult.OK )
{
try
{
using( StreamReader reader = new StreamReader(
ImportFileDialo g.FileName ) )
{
string line = null;
while( ( line = reader.ReadLine () ) != null )
{
// add member to queue and clear text box
pMemberQueue.En queue( line );
}

// update the QueuedListBox
SyncLists();
}
}
catch( Exception ex )
{
MessageBox.Show ( "Exception: " + ex.ToString() );
}
}
}

#endregion Form Event Handlers
}
}

I commented the Icon setting line because I wasn't sure if it was
needed. I can't verify that compiles, it should, all I did was remove
the references to the other forms which aren't valid for this problem.

Thanks for any help, this is driving me nuts.

**Jon Skeet [C# MVP]** · Jan 30 '06, 11:15 AM

Re: Thread won't start...

taylorjonl wrote:

<snip mammoth code>

That's really not short, is it?
[color=blue]
>From the page I referred you to: "Anything which is unnecessary should[/color]
be removed."

Do you really believe that there's nothing in the code you posted which
isn't relevant to the question? How about the checkboxes, the text box
etc? As it is, there's far too much code to look through. If you pare
down the code to the bare minimum, you may well find the problem
yourself.

You definitely *do* have a problem calling SyncLists() inside
ThreadProc() though, for the reasons I gave before.
[color=blue]
> I commented the Icon setting line because I wasn't sure if it was
> needed. I can't verify that compiles, it should, all I did was remove
> the references to the other forms which aren't valid for this problem.[/color]

Why can't you verify that it compiles? Just bring up a command line
with the appropriate variables set (there's a batch file to set them if
you want), cut and paste your code into a text file, and run csc.
That's what I'd be doing, so I don't see what's likely to stop you from
being able to do the same.

Jon

**taylorjonl** · Jan 30 '06, 12:25 PM

Re: Thread won't start...

Sorry if I pasted too much code, didn't know how much you wanted.

using System;
using System.Drawing;
using System.Collecti ons;
using System.Componen tModel;
using System.Windows. Forms;
using System.Data;
using System.IO;
using System.Threadin g;

namespace Issue
{
/// <summary>
/// Summary description for Form1.
/// </summary>
public class MainForm : System.Windows. Forms.Form
{
private System.Componen tModel.IContain er components;
private System.Windows. Forms.Button StartButton;
private System.Windows. Forms.Button StopButton;

// member processing variables
private Thread pProcessingThre ad;
private bool bStopSignal;

public MainForm()
{
//
// Required for Windows Form Designer support
//
InitializeCompo nent();

//
// TODO: Add any constructor code after InitializeCompo nent call
//

// setup member processing variables
bStopSignal = true;
}

/// <summary>
/// Clean up any resources being used.
/// </summary>
protected override void Dispose( bool disposing )
{
if( disposing )
{
if (components != null)
{
components.Disp ose();
}
}
base.Dispose( disposing );
}

/// <summary>
/// </summary>
private void ThreadProc()
{
MessageBox.Show ( "Please browse to the issue viewer base URL to
start" );

string member = null;
while( !bStopSignal )
{
Thread.Sleep( 100 );
}
}

#region Windows Form Designer generated code
/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeCompo nent()
{
this.components = new System.Componen tModel.Containe r();
System.Resource s.ResourceManag er resources = new
System.Resource s.ResourceManag er(typeof(MainF orm));
this.StartButto n = new System.Windows. Forms.Button();
this.StopButton = new System.Windows. Forms.Button();

//
// StartButton
//
this.StartButto n.Location = new System.Drawing. Point(120, 160);
this.StartButto n.Name = "StartButto n";
this.StartButto n.Size = new System.Drawing. Size(160, 32);
this.StartButto n.TabIndex = 5;
this.StartButto n.Text = "Start";
this.StartButto n.Click += new
System.EventHan dler(this.Start Button_Click);
//
// StopButton
//
this.StopButton .Enabled = false;
this.StopButton .Location = new System.Drawing. Point(120, 208);
this.StopButton .Name = "StopButton ";
this.StopButton .Size = new System.Drawing. Size(160, 32);
this.StopButton .TabIndex = 6;
this.StopButton .Text = "Stop";
this.StopButton .Click += new
System.EventHan dler(this.StopB utton_Click);
//
// MainForm
//
this.AutoScaleB aseSize = new System.Drawing. Size(5, 13);
this.ClientSize = new System.Drawing. Size(288, 267);
this.Controls.A dd(this.StopBut ton);
this.Controls.A dd(this.StartBu tton);
this.FormBorder Style =
System.Windows. Forms.FormBorde rStyle.FixedDia log;
this.MaximizeBo x = false;
this.Name = "MainForm";
this.Text = "Issue Closing Daemon";
this.ResumeLayo ut(false);

}
#endregion

/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main()
{
// start application
Application.Run ( new MainForm() );
}

/// <summary>
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void StartButton_Cli ck(object sender, System.EventArg s e)
{
if( bStopSignal )
{
// disable controls that aren't valid when running
StartButton.Ena bled = false;

// enable controls that are valid when running
StopButton.Enab led = true;

// start the processing thread
bStopSignal = false;
MessageBox.Show ( "Starting Processing Thread" );
(pProcessingThr ead = new Thread( new ThreadStart( ThreadProc )
)).Start();
}
}

/// <summary>
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void StopButton_Clic k(object sender, System.EventArg s e)
{
// enable controls that are valid when stopped
StartButton.Ena bled = true;

// disable controls that aren't valid when stopped
StopButton.Enab led = false;

// stop the processing thread
bStopSignal = true;
if( pProcessingThre ad != null )
{
MessageBox.Show ( "Stopping Processing Thread" );
pProcessingThre ad.Join();
pProcessingThre ad = null;
}
}
}
}

That is the bare minimum and I have compile it. It works as expected.
Something is very wrong in my code. I am going to do another test with
only the WebBrowser control removed as I would expect this to be the
cause.

Sorry about not trying to compile from command line before, I tried to
that from work a while ago and it crashed my system. I don't have any
batch file with the environmental variables but just added csc.exe to
the path and it compiles. If you have this batch file please post it
because if I can compile at work I can find the problem.

Thanks for the help, I will post once I have found a solution.

**Jon Skeet [C# MVP]** · Jan 30 '06, 07:35 PM

Re: Thread won't start...

taylorjonl <taylorjonl@gma il.com> wrote:[color=blue]
> Sorry if I pasted too much code, didn't know how much you wanted.[/color]

The hint was in the page I linked to :)

<snip>
[color=blue]
> That is the bare minimum and I have compile it. It works as expected.
> Something is very wrong in my code. I am going to do another test with
> only the WebBrowser control removed as I would expect this to be the
> cause.[/color]

Right. Now you've got a minimal base, you can gradually add bits until
it fails.
[color=blue]
> Sorry about not trying to compile from command line before, I tried to
> that from work a while ago and it crashed my system. I don't have any
> batch file with the environmental variables but just added csc.exe to
> the path and it compiles. If you have this batch file please post it
> because if I can compile at work I can find the problem.[/color]

There should be one that came with Visual Studio. Look under the Visual
Studio installation directory for vsvars32.bat (VS.NET 2003) or
vcvarsall.bat (VS 2005).

--
Jon Skeet - <skeet@pobox.co m>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
If replying to the group, please do not mail me too

Thread won't start...

Thread won't start...

Comment

Comment

Comment

Comment

Comment