To all,
I have a GUI program (use c#), and I have create a Thread for loading
some bulk data, I also arrange the GUI program like this:
1) load a form showing "Wait for loading..." etc
2) a Thread is then created to load the bulk data
3) after the thread has completed, close the "Wait for loading" form
4) show the main form for the GUI program
The problem is that if I show the "waiting" form, that form's GUI will
not work properly (no repaint event and hangs around, ie. a blank
window), the worse thing is that the Thread may not work properly too
(actually it will stop executing, waiting for locks, maybe ??)
But if I start the Thread without showing any forms; it works
perfectly ????!
What's wrong ?? (the same things happen under .Net Compact Framework)
[code snippet for the main GUI form]
public class Trial04_02 : System.Windows. Forms.Form
{
private System.Windows. Forms.Label label1;
private System.Windows. Forms.Button button1;
private System.Componen tModel.Containe r components = null;
private Trial04_01 mFrmSplash;
private Thread mThr_Main;
private System.Windows. Forms.ListBox listBox1;
private CommonEngine02 mCEng;
public Trial04_02()
{
InitializeCompo nent();
init ();
}
private void InitializeCompo nent() {}
protected void init ()
{
// 1st show splash form
this.mFrmSplash = new Trial04_01 ();
//this.mFrmSplash .Show ();
// 2nd create a thread to load sth...
// CommonEngine02 is a class containing the
// data loading function
this.mCEng = new CommonEngine02 (); this.mThr_Main = new Thread
(new ThreadStart (this.mCEng.thr eadTask));
this.mThr_Main. Start ();
this.mThr_Main. Join ();
this.mFrmSplash .Close ();
// 3rd other setup(s)
// get back the loaded data
System.Collecti ons.ArrayList oArr
= this.mCEng.getA rr_Data ();
for (int i=0; i<oArr.Count; i++)
{
this.listBox1.I tems.Add (oArr[i]);
}
this.Show ();
}
static void Main ()
{
Application.Run (new Trial04_02 ());
}
}
}
[/code]
From Jason (Kusanagihk)
13  3623 
Hi Jason,
It looks like your form "mFrmSplash " (main thread) waits at
"this.mThr_Main .Join()" line, so it can not be "invalidate d".
I can propose:
A) "mFrmSplash.Clo se() && this.Show()" within
thread "mThr_Main" .
or
B) run third thread that will wait ("this.mThr_Mai n.Join()")
and then will close the splash form and show the main window.
Regads
Marcin To all,
I have a GUI program (use c#), and I have create a Thread for loading
some bulk data, I also arrange the GUI program like this:
1) load a form showing "Wait for loading..." etc
2) a Thread is then created to load the bulk data
3) after the thread has completed, close the "Wait for loading" form
4) show the main form for the GUI program
The problem is that if I show the "waiting" form, that form's GUI will
not work properly (no repaint event and hangs around, ie. a blank
window), the worse thing is that the Thread may not work properly too
(actually it will stop executing, waiting for locks, maybe ??)
But if I start the Thread without showing any forms; it works
perfectly ????!
What's wrong ?? (the same things happen under .Net Compact Framework)
[code snippet for the main GUI form]
public class Trial04_02 : System.Windows. Forms.Form
{
private System.Windows. Forms.Label label1;
private System.Windows. Forms.Button button1;
private System.Componen tModel.Containe r components = null;
private Trial04_01 mFrmSplash;
private Thread mThr_Main;
private System.Windows. Forms.ListBox listBox1;
private CommonEngine02 mCEng;
public Trial04_02()
{
InitializeCompo nent();
init ();
}
private void InitializeCompo nent() {}
protected void init ()
{
// 1st show splash form
this.mFrmSplash = new Trial04_01 ();
//this.mFrmSplash .Show ();
// 2nd create a thread to load sth...
// CommonEngine02 is a class containing the
// data loading function
this.mCEng = new CommonEngine02 (); this.mThr_Main = new Thread
(new ThreadStart (this.mCEng.thr eadTask));
this.mThr_Main. Start ();
this.mThr_Main. Join ();
this.mFrmSplash .Close ();
// 3rd other setup(s)
// get back the loaded data
System.Collecti ons.ArrayList oArr
= this.mCEng.getA rr_Data ();
for (int i=0; i<oArr.Count; i++)
{
this.listBox1.I tems.Add (oArr[i]);
}
this.Show ();
}
static void Main ()
{
Application.Run (new Trial04_02 ());
}
}
}
[/code]
From Jason (Kusanagihk)
Jason Jacob <50******@alumn i.cityu.edu.hk> wrote: I have a GUI program (use c#), and I have create a Thread for loading
some bulk data, I also arrange the GUI program like this:
1) load a form showing "Wait for loading..." etc
2) a Thread is then created to load the bulk data
3) after the thread has completed, close the "Wait for loading" form
4) show the main form for the GUI program
There's no point in creating a new thread if you're immediately going
to call Join on it. Instead, you need to run the UI thread as normal,
and have some kind of call when the load finishes to tell the loading
screen to close.
See http://www.pobox.com/~skeet/csharp/multithreading.html for more
information.
--
Jon Skeet - <sk***@pobox.co m> http://www.pobox.com/~skeet
If replying to the group, please do not mail me too
To Jon,
I've changed the code as you've said, actually there is no change in
the problem:
public Form1()
{
InitializeCompo nent();
oFrm2 = new Form2 ();
Thread t1 = new Thread
(new ThreadStart (oFrm2.threadTa sk));
t1.Start ();
loaderTask ();
oFrm2.mBool_Sto p = true;
lock (this)
{
t1.Join ();
oFrm2.Close ();
}
}
The above code is the constructor code for the operation, threadTask
will change the Splash Form's Label's Text, but when got them
executed, the Splash Form's UI is not updating properly...
But then, I've tried to use oFrm2.ShowDialo g () instead of oFrm2.Show
(), the result is that the Splash Form can be shown properly, but
actually it is not a Thread, since the form is waiting for you to
close it (Dialog), then it will continue the other tasks started
earlier...
From Jason (Kusanagihk)
Jason Jacob <50******@alumn i.cityu.edu.hk> wrote: I've changed the code as you've said, actually there is no change in
the problem:
public Form1()
{
InitializeCompo nent();
oFrm2 = new Form2 ();
Thread t1 = new Thread
(new ThreadStart (oFrm2.threadTa sk));
t1.Start ();
loaderTask ();
oFrm2.mBool_Sto p = true;
lock (this)
{
t1.Join ();
oFrm2.Close ();
}
}
The above code is the constructor code for the operation, threadTask
will change the Splash Form's Label's Text, but when got them
executed, the Splash Form's UI is not updating properly...
The constructor is not going to finish executing until the thread has
finished though, so you aren't starting a message pump.
But then, I've tried to use oFrm2.ShowDialo g () instead of oFrm2.Show
(), the result is that the Splash Form can be shown properly, but
actually it is not a Thread, since the form is waiting for you to
close it (Dialog), then it will continue the other tasks started
earlier...
In the above, you aren't even showing oFrm2 at all. You should start
the thread and then have that tell the splash screen to close when it's
finished. Using Thread.Join is *not* a good idea when called from the
UI thread.
--
Jon Skeet - <sk***@pobox.co m> http://www.pobox.com/~skeet
If replying to the group, please do not mail me too
To Jon,
I've modified the code, and start the Thread outside the constructor.
Now it is works a bit "normal" to me. However the Splash Form still
can't change its GUI's properties (eg. I want to change a Label's text
showing the Time elapsed from loading etc..., it still won't update
for now)
And Join a UI Thread is not a *good* idea, what does that mean ??
the new code -
namespace Splash_Trial.Trial02
-
{
-
public class Form1 : System.Windows.Forms.Form
-
{
-
..........
-
-
// Constructor
-
public Form1()
-
{
-
InitializeComponent();
-
-
this.Show ();
-
}
-
-
protected void loaderTask ()
-
{
-
// do some bulky things such as reading lots of data
-
...............
-
}
-
-
protected override void Dispose( bool disposing ){ //.... }
-
-
protected void threadTask ()
-
{
-
oFrm2 = new Form2 ();
-
Thread t1 = new Thread
-
(new ThreadStart (oFrm2.threadTask));
-
t1.Start ();
-
-
loaderTask (); // the bulky work
-
oFrm2.mBool_Stop = true;
-
t1.Join ();
-
oFrm2.Close ();
-
}
-
-
[STAThread]
-
static void Main()
-
{
-
Form1 oFrm1 = new Form1 ();
-
oFrm1.threadTask ();
-
Application.Run(oFrm1);
-
}
-
}
-
}
-
-
From Jason (Kusanagihk)
Jason Jacob <50******@alumn i.cityu.edu.hk> wrote: I've modified the code, and start the Thread outside the constructor.
Now it is works a bit "normal" to me. However the Splash Form still
can't change its GUI's properties (eg. I want to change a Label's text
showing the Time elapsed from loading etc..., it still won't update
for now)
You need to use Control.Invoke or Control.BeginIn voke to update the UI
from a non-UI thread. Did you read the article I pointed you to before?
It has an example of doing this kind of thing.
And Join a UI Thread is not a *good* idea, what does that mean ??
It means you shouldn't do it, because your app's UI won't be able to
process any events (like painting) until the other thread has finished.
--
Jon Skeet - <sk***@pobox.co m> http://www.pobox.com/~skeet
If replying to the group, please do not mail me too
To Jon
I've read the "Threading in Windows Form" from your link. I have
modified the code to use Control.Invoke, but still some strange
things. If I don't add a Refresh () code, the UI won't update; if I
try to click or do anything on the splash form, the UI will not
respond (a "not responding" appears on the form's title bar.
using System;
using System.Drawing;
using System.Collecti ons;
using System.Componen tModel;
using System.Windows. Forms;
using System.Threadin g;
namespace ThreadCookBook. Trial05
{
public class Form2 : System.Windows. Forms.Form
{
private System.Windows. Forms.Label label1;
private System.Componen tModel.Containe r components = null;
public delegate void invokeTask ();
public invokeTask mInvokeTask;
private bool mBool_Stop = false;
public Form2()
{
InitializeCompo nent();
this.mInvokeTas k = new invokeTask
(this.realInvok eTask);
}
public void realInvokeTask ()
{
Random ran = new Random
((int) System.DateTime .Now.Ticks);
int iR = ran.Next (255);
int iG = ran.Next (255);
int iB = ran.Next (255);
this.label1.Tex t = System.DateTime .Now + "";
this.BackColor = Color.FromArgb (iR, iG, iB);
this.Refresh ();
}
protected override void Dispose( bool disposing ) { //... }
private void InitializeCompo nent() { //... }
public void threadTask ()
{
if (this.Visible == false)
{
this.Show ();
}
while (!this.mBool_St op)
{
Invoke (this.mInvokeTa sk);
Thread.Sleep (2000);
}
}
public void setStop (bool flag)
{
this.mBool_Stop = flag;
}
}
}
From Jason (Kusanagihk)
Jason Jacob <50******@alumn i.cityu.edu.hk> wrote: I've read the "Threading in Windows Form" from your link. I have
modified the code to use Control.Invoke, but still some strange
things. If I don't add a Refresh () code, the UI won't update; if I
try to click or do anything on the splash form, the UI will not
respond (a "not responding" appears on the form's title bar.
Well you're now not showing the code which creates the new thread.
Please post a *complete* program which demonstrates the problem, and
we'll be able to get somewhere.
--
Jon Skeet - <sk***@pobox.co m> http://www.pobox.com/~skeet
If replying to the group, please do not mail me too
To Jon
The Main Form's code
using System;
using System.Drawing;
using System.Collecti ons;
using System.Componen tModel;
using System.Windows. Forms;
using System.Threadin g;
namespace ThreadCookBook. Trial05
{
public class Form1 : System.Windows. Forms.Form
{
private System.Windows. Forms.ListBox listBox1;
private System.Windows. Forms.Button button1;
private System.Componen tModel.Containe r components = null;
private Thread mThr_ThreadTask ;
// a class to load some bulky data
private CommonEngine02 mCEng02;
// the Splash Form
private Form2 mFrm02;
public Form1()
{
InitializeCompo nent();
init ();
}
protected override void Dispose( bool disposing ) { //... }
private void InitializeCompo nent() { //... }
protected void init ()
{
this.mCEng02 = new CommonEngine02 ();
}
protected void loaderTask ()
{
this.threadTask ();
// blocking, load the bulky data ...
this.mCEng02.th readTask ();
// try to stop the loop in the Splash Form
lock (this)
{
this.mFrm02.set Stop (true);
this.mFrm02.Clo se ();
}
// get back the bulky data and add them to a listBox
ArrayList oArr = this.mCEng02.ge tArr_Data ();
for (int i=0; i<oArr.Count; i++)
{
this.listBox1.I tems.Add (oArr[i]);
}
}
public void threadTask ()
{
this.mFrm02 = new Form2 ();
this.mThr_Threa dTask = new Thread
(new ThreadStart (this.mFrm02.th readTask));
this.mThr_Threa dTask.Start ();
}
static void Main ()
{
// maybe here's where the problem is...
Form1 oFrm01 = new Form1 ();
oFrm01.loaderTa sk ();
Application.Run (oFrm01);
}
}
}
From Jason (Kusanagihk)
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