BackGroundWorker.ProgressChanged "Cross-thread operation not valid" at 2nd/3th/... progress

Oh I should also mention that your error here doesn't have anything to do
with the cross-thread Outlook access but I would avoid that anyway.

Your error message here is the same thing Dmytro said about cross-thread UI
calls. Something you are doing in DoWork (which is in a background thread)
is modifying the data grid. You can't do any UI access in DoWork. Only in
ProgressChanged or RunWorkerCompleted.

But again, I would avoid accessing the Outlook API from a background thread.
It is not thread-safe and behaves unpredictably whether or not you employ
locking.

--
Josh Einstein
Einstein Technologies
Microsoft Tablet PC MVP
Tablet Enhancements for Outlook 2.0 - Try it free for 14 days
www.tabletoutlook.com


"Pieter" wrote in message
...
Hi,

I've tryed it, but it didn't work either :-/
And isn't the BackGroundWorker designed so we shouldn't worry anymore
about those Invoke and Delegates-stuff?

This is my new code with Invoke, which doesn't work either... :-/

Private Sub bgwInfoOutlook_ProgressChanged(ByVal sender As Object,
ByVal e As System.ComponentModel.ProgressChangedEventArgs) Handles
bgwInfoOutlook.ProgressChanged
Try
SetDataSource()
Catch ex As Exception
ErrorMessage(ex)
End Try
End Sub

Delegate Sub SetDgvCallback()

Private Sub SetDataSource()
If Me.dgvAdd.InvokeRequired Then
Dim d As New SetDgvCallback(AddressOf SetDataSource)
Me.Invoke(d, Nothing)
Else
Me.dgvAdd.DataSource = Nothing
Me.dgvAdd.DataSource = docCtrl.InfoList
End If
End Sub

And the werit thing is: the Me.dgvAdd.InvokeRequired returns False...

"Dmytro Lapshyn [MVP]" wrote in message
...
Hi Pieter,

As far as I know, .NET 2.0 strictly prohibits any access to the user
interface from background worker threads. This wasn't allowed in .NET 1.1
either, but in that version one sometimes could get away with violating
the rule. Now you'll get the "Cross-thread operation not valid" almost
for sure.

Therefore, to do any updates to the UI properly, you should use the
Control.Invoke method to run the UI update code on the UI thread.

"Josh Einstein" wrote in message
...

Your error message here is the same thing Dmytro said about cross-thread
UI calls. Something you are doing in DoWork (which is in a background
thread) is modifying the data grid.

Well actually it isn't :-/
And I don't have the exception while the Dowork is performing its actions:
it happens when the ProgressChanged-event fires...

You'll have to recheck your code. Set a breakpoint and look at the threads
window. You are definitely accessing the UI from the background thread
somewhere. ProgressChanged and RunWorkerCompleted are raised on the UI
thread. (Which is why InvokeRequired returns false.)

--
Josh Einstein
Einstein Technologies
Microsoft Tablet PC MVP
Tablet Enhancements for Outlook 2.0 - Try it free for 14 days
www.tabletoutlook.com


"Pieter" wrote in message
...
"Josh Einstein" wrote in message
...

Your error message here is the same thing Dmytro said about cross-thread
UI calls. Something you are doing in DoWork (which is in a background
thread) is modifying the data grid.

Well actually it isn't :-/
And I don't have the exception while the Dowork is performing its actions:
it happens when the ProgressChanged-event fires...