Repeated Adding,Removing control from form

[Brad Huff]

I have included a snippet below which illustrates the
problem with adding and removing controls in a repeating
fashion. At least on my computer (Windows XP) the
program crashes after several thousand iterations. Is
there a way to correct this simple program so it doesn't
crash or is there a bug with .NET 1.1?

Thanks, Brad


using System.ComponentModel;
using System.Windows.Forms;
using System.Drawing;
using System.IO;
using CustomDialogs;
using CustomControls;
using System.Threading;

public class Test{

public class MyForm:Form{
XButton button = new XButton();
XButton test = new XButton();
int count;

public MyForm(): base() {
InitializeComponent();
}
private void InitializeComponent(){
this.Width = 1000;
this.Height = 900;
this.Controls.Add(button);
button.Click +=
new EventHandler(click);
test.Location = new Point(300,300);
}
void click (object sender, EventArgs e){
for (int i = 0;i<30000;i++){
Controls.Add(test);
Controls.Remove(test);
count++;
button.Text = count.ToString();
button.Refresh();
}
}

}
public static void Main(string[] args)
{
MyForm form = new MyForm();
Application.Run(form);

}

}

 

[Iulian Ionescu]

I duplicated this and indeed it crashes at about
iteration no. 4735. There is no onbious error message, so
I just assume that the memory gets full and a process of
using virtual memory starts and for some reaon it is not
sucessfull... This is really weird... If i force the
application to shut down I also see the button changed
to "30000", which means that somehow the loop finishes...

 

[Brad Huff]

What is also interesting is that the program will crash
at any spot, the iteration crashing at just about any
time.

Brad Huff

-----Original Message-----

I duplicated this and indeed it crashes at about
iteration no. 4735. There is no onbious error message, so
I just assume that the memory gets full and a process of
using virtual memory starts and for some reaon it is not
sucessfull... This is really weird... If i force the
application to shut down I also see the button changed
to "30000", which means that somehow the loop finishes...

-----Original Message-----
I have included a snippet below which illustrates the
problem with adding and removing controls in a repeating
fashion. At least on my computer (Windows XP) the
program crashes after several thousand iterations. Is
there a way to correct this simple program so it doesn't
crash or is there a bug with .NET 1.1?

Thanks, Brad


using System.ComponentModel;
using System.Windows.Forms;
using System.Drawing;
using System.IO;
using CustomDialogs;
using CustomControls;
using System.Threading;

public class Test{

public class MyForm:Form{
XButton button = new XButton();
XButton test = new XButton();
int count;

public MyForm(): base() {
InitializeComponent();
}
private void InitializeComponent(){
this.Width = 1000;
this.Height = 900;
this.Controls.Add(button);
button.Click +=
new EventHandler(click);
test.Location = new Point(300,300);
}
void click (object sender, EventArgs e){
for (int i = 0;i<30000;i++){
Controls.Add(test);
Controls.Remove(test);
count++;
button.Text = count.ToString();
button.Refresh();
}
}

}
public static void Main(string[] args)
{
MyForm form = new MyForm();
Application.Run(form);

}

}
.

.

 

[ClayB [Syncfusion]]

I think the message queue is being overrun with unprocessed messages in this
snippet. Adding a DoEvents call allowed it to finish the 30000 iterations
for me.

Controls.Add(test);
Application.DoEvents();
Controls.Remove(test);

========================
Clay Burch, .NET MVP

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