vb .net Debugging Step Over not updating my Form

Johnnytoxic · 20 Oct 2009 at 15:24

Hi,

I'm just starting in .net and I have a listbox that I'm updating in code.

When I'm debugging and stepping over a bit of code that inserts a new item, the form is not updating in realtime.

Only when I click F5 to finish and continue, the form then updates.

Any ideas?

~J~ · 20 Oct 2009 at 15:25

Have you tried validating the control to force a refresh?

Johnnytoxic · 20 Oct 2009 at 15:28

~J~ said:
Have you tried validating the control to force a refresh?

Please enlighten me.

I've not done vb programming since 6.

topbanana · 20 Oct 2009 at 15:40

First, try a rebuild. Then, try disabling edit and continue.

Johnnytoxic · 20 Oct 2009 at 15:47

topbanana said:
First, try a rebuild. Then, try disabling edit and continue.

Didn't work.

The form just says "Not Responding".

When I click F5 to continue, the form will be normal again.

s-p · 20 Oct 2009 at 18:16

Have a read of Application.DoEvents method (http://msdn.microsoft.com/en-us/library/system.windows.forms.application.doevents.aspx)

Johnnytoxic · 20 Oct 2009 at 18:24

s-p said:
Have a read of Application.DoEvents method (http://msdn.microsoft.com/en-us/library/system.windows.forms.application.doevents.aspx)

Thanks that helps.

I just remember the older versions of vb would update the form window as you step through each line of code.

Is the problem to do with multithreads?

s-p · 20 Oct 2009 at 19:46

Johnnytoxic said:
Thanks that helps.

I just remember the older versions of vb would update the form window as you step through each line of code.

Is the problem to do with multithreads?

The "problem" can I guess be explained by the fact your application is running under a single thread (there's a good reason for this). In essence, you're effectively asking your application to do two things:

1. Execute your function which updates the listbox control.
2. Re-paint the listbox and any other controls following the changes implemented by the previous function.

As it stands, I don't believe you have a functional requirement to update the form's display whilst the code is being processed? In which case, just use the Immediate window and monitor your form's controls from within there.