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

Hi,

I'm having some weird problem using the BackGroundWorker in an Outlook
(2003) Add-In, with VB.NET 2005:
I'm using the BackGroundWorker to get the info of some mailitems, and
after each item I want to raise the ProgressChanged-event to update the
DataGridView.
It works fine when only one Progresschanged is fired, but at the second,
third, fopurth etc it raises everytile a 'Cross-thread operation not
valid"-exception on lmy DataGridView (dgvAdd).

Any idea what causes this problem? What am I doing wrong? What is the
problem here?

Any help our hints would be really appreciated!

Thanks a lot in advance,

Pieter
This is my code:
Me.bgwInfoOutlook.RunWorkerAsync(Me.m_colItems)

Private Sub bgwInfoOutlook_DoWork(ByVal sender As Object, ByVal e As
System.ComponentModel.DoWorkEventArgs) Handles bgwInfoOutlook.DoWork
Dim col As Collection = e.Argument
AddHandler docCtrl.InfoListChanged, AddressOf InfoListChanged
Dim str As String = docCtrl.GetOutlookInfo(col,
Me.m_objOutlookFolder)
e.Result = docCtrl.AddedDocMails
End Sub

Private Sub InfoListChanged(ByVal sender As Object, ByVal e As
EventArgs)
Me.bgwInfoOutlook.ReportProgress(0)
End Sub

Private Sub bgwInfoOutlook_ProgressChanged(ByVal sender As Object,
ByVal e As System.ComponentModel.ProgressChangedEventArgs) Handles
bgwInfoOutlook.ProgressChanged
'bind the list to the datagridview
Try
Me.dgvAdd.DataSource = Nothing
Me.dgvAdd.DataSource = docCtrl.InfoList
Catch ex As Exception
ErrorMessage(ex)
End Try
End Sub
This is the exception:

{"Cross-thread operation not valid: Control 'dgvAdd' accessed from a
thread other than the thread it was created on."}
System.InvalidOperationException: {"Cross-thread operation not valid:
Control 'dgvAdd' accessed from a thread other than the thread it was
created on."}
Data: {System.Collections.ListDictionaryInternal}
HelpLink: Nothing
InnerException: Nothing
Message: "Cross-thread operation not valid: Control 'dgvAdd' accessed
from a thread other than the thread it was created on."
Source: "System.Windows.Forms"
StackTrace: " at System.Windows.Forms.Control.get_Handle()
at System.Windows.Forms.Control.get_InternalHandle()
at System.Windows.Forms.Control.get_CreateParams()
at System.Windows.Forms.ScrollBar.get_CreateParams()
at System.Windows.Forms.VScrollBar.get_CreateParams()
at System.Windows.Forms.Control.UpdateBounds(Int32 x, Int32 y, Int32
width, Int32 height)
at System.Windows.Forms.Control.SetBoundsCore(Int32 x, Int32 y, Int32
width, Int32 height, BoundsSpecified specified)
at System.Windows.Forms.Control.SetBounds(Int32 x, Int32 y, Int32 width,
Int32 height, BoundsSpecified specified)
at System.Windows.Forms.Control.set_Bounds(Rectangle value)
at System.Windows.Forms.DataGridView.LayoutScrollBars ()
at System.Windows.Forms.DataGridView.ComputeLayout()
at System.Windows.Forms.DataGridView.PerformLayoutPri vate(Boolean
useRowShortcut, Boolean computeVisibleRows, Boolean
invalidInAdjustFillingColumns, Boolean repositionEditingControl)
at
System.Windows.Forms.DataGridView.OnColumnWidthCha nged(DataGridViewColumnEventArgs
e)
at
System.Windows.Forms.DataGridView.OnBandThicknessC hanged(DataGridViewBand
dataGridViewBand)
at System.Windows.Forms.DataGridViewBand.set_Thicknes sInternal(Int32
value)
at System.Windows.Forms.DataGridView.AdjustFillingCol umns()
at System.Windows.Forms.DataGridView.ComputeLayout()
at System.Windows.Forms.DataGridView.PerformLayoutPri vate(Boolean
useRowShortcut, Boolean computeVisibleRows, Boolean
invalidInAdjustFillingColumns, Boolean repositionEditingControl)
at System.Windows.Forms.DataGridView.ResetUIState(Boo lean
useRowShortcut, Boolean computeVisibleRows)
at
System.Windows.Forms.DataGridViewRowCollection.OnC ollectionChanged_PreNotification(CollectionChangeA ction
cca, Int32 rowIndex, Int32 rowCount, DataGridViewRow& dataGridViewRow,
Boolean changeIsInsertion)
at
System.Windows.Forms.DataGridViewRowCollection.OnC ollectionChanged(CollectionChangeEventArgs
e, Int32 rowIndex, Int32 rowCount, Boolean changeIsDeletion, Boolean
changeIsInsertion, Boolean recreateNewRow, Point newCurrentCell)
at System.Windows.Forms.DataGridViewRowCollection.Ins ertInternal(Int32
rowIndex, DataGridViewRow dataGridViewRow, Boolean force)
at
System.Windows.Forms.DataGridView.DataGridViewData Connection.ProcessListChanged(ListChangedEventArgs
e)
at
System.Windows.Forms.DataGridView.DataGridViewData Connection.currencyManager_ListChanged(Object
sender, ListChangedEventArgs e)
at
System.Windows.Forms.CurrencyManager.OnListChanged (ListChangedEventArgs e)
at System.Windows.Forms.CurrencyManager.List_ListChan ged(Object sender,
ListChangedEventArgs e)
at
System.ComponentModel.BindingList`1.OnListChanged( ListChangedEventArgs e)
at System.ComponentModel.BindingList`1.FireListChange d(ListChangedType
type, Int32 index)
at System.ComponentModel.BindingList`1.InsertItem(Int 32 index, T item)
at System.Collections.ObjectModel.Collection`1.Add(T item)
at BaseFramework.clsBaseList`1.Add(T item) in D:\NET Projecten\Code
Source Sodimex - Ghost\BaseFramework\clsBaseList.vb:line 461
at DocControl.clsDocControl.GetOutlookInfo(Collection colItems, Object
oFolder, Boolean blnAttachments) in D:\NET Projecten\Code Source Sodimex -
Ghost\DocControl\Business Layer\clsDocControl.vb:line 597"
TargetSite: {System.Reflection.RuntimeMethodInfo}

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.

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]" <x-****@no-spam-please.hotpop.com> wrote in message
news:%2****************@TK2MSFTNGP11.phx.gbl...

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.

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]" <x-****@no-spam-please.hotpop.com> wrote in message
news:%2****************@TK2MSFTNGP11.phx.gbl...

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.

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.

The problem is more serious. You shouldn't be accessing any Outlook
objects from a background thread. It just won't work right and you'll have
all sorts of problems ranging from error messages to mysterious
OUTLOOK.EXE processes that won't shut down.

I'm afraid all of your communication with Outlook has to be done on the
same thread that calls your connect method. That would be the UI thread.
The only "async" methods you can use are the advanced search api's but I
believe even they are single-threaded much like a UI timer is.

--
Josh Einstein
Einstein Technologies
Microsoft Tablet PC MVP
Tablet Enhancements for Outlook 2.0 - Try it free for 14 days
www.tabletoutlook.com
"Pieter" <pi**********@hotmail.com> wrote in message
news:uO**************@TK2MSFTNGP11.phx.gbl...

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]" <x-****@no-spam-please.hotpop.com> wrote in
message news:%2****************@TK2MSFTNGP11.phx.gbl...

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" <jo**********@hotmail.com> wrote in message
news:OW**************@TK2MSFTNGP14.phx.gbl...

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...

Why? COM in general (especially out-of-proc COM), and Outlook is
particular can handle cross thread/process calls just fine - all Outlook
objects are apartment threaded, so all calls will end up on the main
Outlook thread anyway.

Dmitry Streblechenko (MVP)
http://www.dimastr.com/
OutlookSpy - Outlook, CDO
and MAPI Developer Tool

"Josh Einstein" <jo**********@hotmail.com> wrote in message
news:OR**************@TK2MSFTNGP09.phx.gbl...

The problem is more serious. You shouldn't be accessing any Outlook
objects from a background thread. It just won't work right and you'll
have all sorts of problems ranging from error messages to mysterious
OUTLOOK.EXE processes that won't shut down.

I'm afraid all of your communication with Outlook has to be done on the
same thread that calls your connect method. That would be the UI thread.
The only "async" methods you can use are the advanced search api's but I
believe even they are single-threaded much like a UI timer is.

--
Josh Einstein
Einstein Technologies
Microsoft Tablet PC MVP
Tablet Enhancements for Outlook 2.0 - Try it free for 14 days
www.tabletoutlook.com
"Pieter" <pi**********@hotmail.com> wrote in message
news:uO**************@TK2MSFTNGP11.phx.gbl...

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]" <x-****@no-spam-please.hotpop.com> wrote in
message news:%2****************@TK2MSFTNGP11.phx.gbl...
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.