Re: Updating controls on a form

kelly,

you may want to look ath this series of 3 articles from chris sells.
it made all the multithreading stuff very clear to me, and helped me figure
out the separate pieces i needed to move information back and forth between
threads, how to safely handle events from one thread and make sure i
correctly manipulated my UI controls on the proper thread.

article  #1 should be all you need here.  #2 and #3 are more advanced
scenarios i think.

[1]http://msdn2.microsoft.com/en-us/library/ms951089.aspx
[2]http://msdn2.microsoft.com/en-us/library/ms951109.aspx
[3]http://msdn2.microsoft.com/en-us/library/ms993020.aspx



-----Original Message-----
From: Discussion forum for developers using Windows Forms to build apps
and controls [mailto:[email protected]]On Behalf Of
Kelly Baker
Sent: Sunday, March 25, 2007 7:18 PM
To: [email protected]
Subject: Re: [DOTNET-WINFORMS] Updating controls on a form


There is no form in my dll.  The Windows form is in the calling executable.
I do want the timer and the code that it runs in a separate thread.  I was
just wondering how I could have it doing the grunt work in a separate
thread, but have shared variables that the properties return, without the
calling executable having to go through all of this.

Thanks,
Kelly

-----Original Message-----
From: Discussion forum for developers using Windows Forms to build apps and
controls [mailto:[email protected]] On Behalf Of Patrick
Steele
Sent: Sunday, March 25, 2007 7:28 AM
To: [email protected]
Subject: Re: [DOTNET-WINFORMS] Updating controls on a form

You should be using the System.Windows.Forms.Timer instead.  From the
documentation on System.Threading.Timer:

"System.Threading.Timer is a simple, lightweight timer that uses
callback methods and is served by thread pool threads. It is not
recommended for use with Windows Forms, because its callbacks do not
occur on the user interface thread. System.Windows.Forms.Timer is a
better choice for use with Windows Forms."

--
Patrick Steele
http://weblogs.asp.net/psteele



-----Original Message-----
From: Discussion forum for developers using Windows Forms to build apps
and controls [mailto:[email protected]] On Behalf Of
Kelly Baker
Sent: Saturday, March 24, 2007 10:37 PM
To: [email protected]
Subject: [DOTNET-WINFORMS] Updating controls on a form


Unless my app is EXTREMELY simple, I get the cross-threading error
message regularly when updating controls on a Windows form.

My latest example involves a dll that runs a System.Threading.Timer,
updating private shared variables.  When it finishes updating, it raises
a NewData event.  My app responds to that event by updating display
controls (labels in this case).  I have to use a delegate and update
them like this:

Private Sub SetText(ByVal [text] as String)
    If Me.Messages.InvokeRequired Then
        Dim d as New SetTextCallBack(AddressOf SetText)
        Me.Invoke(d, New Object() {[text]})
    Else
        Me.Messages.Text = [text]
    End If
End Sub

I have to write a different routine like this for each control on the
form that I want to update.  Is there a better way?  Please?