BackgroundWorke r thread locking UI

John,
You need to do the actual work in the DoWork event handler.

I would call LoadComputerDro pDown directly from DoWork, when
LoadComputerDro pDown completes I would Invoke a method on the UI that
"returns" the dataset...

Something like:

'Code
Private Delegate Sub LoadComputerDel egate(ByVal table As DataTable)

'called from form load

Protected Overrides Sub OnLoad(ByVal e As System.EventArg s)
MyBase.OnLoad(e )
tsStatus.Text = "Loading Computers. Please wait..."
bgLoadComputers .RunWorkerAsync ()
End Sub
'sub that does the work

Private Sub bgLoadComputers _DoWork(ByVal sender As System.Object, ByVal
e As System.Componen tModel.DoWorkEv entArgs) Handles bgLoadComputers .DoWork
System.Threadin g.Thread.Sleep( TimeSpan.FromSe conds(2))
LoadComputerDro pDown()
End Sub

Private Sub LoadComputerDro pDown()
Dim dtComputers As New DataTable("Comp uters")
dtComputers.Col umns.Add("Compu ter Name", GetType(String) )
'get the computers on the domain
Try
Dim enTry As DirectoryEntry = New
DirectoryEntry( "LDAP://TSBRADLEY")
Dim mySearcher As DirectorySearch er = New
DirectorySearch er(enTry)
mySearcher.Filt er = ("(objectClass= Computer)")
Dim resEnt As SearchResult
For Each resEnt In mySearcher.Find All
Try
Dim tmpID As String =
Mid(resEnt.GetD irectoryEntry.N ame.ToString, 4)
If Mid(tmpID, 1, 2) = "L1" Then
Dim rwComputer As DataRow
rwComputer = dtComputers.New Row
rwComputer("Com puter Name") =
(Mid((resEnt.Ge tDirectoryEntry ().Name.ToStrin g), 4))
dtComputers.Row s.Add(rwCompute r)
End If
Invoke(New LoadComputerDel egate(AddressOf
SetDomainComute rs), dtComputers)
Catch ex As Exception
Invoke(New LoadComputerDel egate(AddressOf
SetDomainComute rs), dtComputers)
End Try
Next
Catch ex As Exception
Invoke(New LoadComputerDel egate(AddressOf SetDomainComute rs),
dtComputers)
End Try
End Sub

Private Sub SetDomainComute rs(ByVal dtComputers As DataTable)
tsStatus.Text = "Computers Loaded..."
cboDomainComute rs.DataSource = dtComputers
cboDomainComute rs.DisplayMembe r = "Computer Name"
End Sub

Note: You should not refer to controls (tsStatus) from the DoWork method.
"John Wright" <ri**********@n otmail.comwrote in message
news:%2******** ********@TK2MSF TNGP05.phx.gbl. ..

>I have a background worker thread that scans the network listing computers
that are connected. I have a delegate that I call that invokes a procdure
that loads a dataset with computer names and then attaches it to a
dropdown. When I run it, my UI freezes until it completes. Any thoughts on
how to do this without freezing the UI?

John
Code

'General Declaration

Private Delegate Sub LoadComputerDel egate()

'called from form load

bgLoadComputers .RunWorkerAsync ()

'sub that does the work

Private Sub bgLoadComputers _DoWork(ByVal sender As System.Object, ByVal e
As System.Componen tModel.DoWorkEv entArgs) Handles bgLoadComputers .DoWork

tsStatus.Text = "Loading Computers. Please wait..."

System.Threadin g.Thread.Sleep( TimeSpan.FromSe conds(2))

Invoke(New LoadComputerDel egate(AddressOf LoadComputerDro pDown))

End Sub

Private Sub LoadComputerDro pDown()

'get the computers on the domain

Try

Dim enTry As DirectoryEntry = New DirectoryEntry( LDAP://[MYDOMAIN])

Dim mySearcher As DirectorySearch er = New DirectorySearch er(enTry)

mySearcher.Filt er = ("(objectClass= Computer)")

Dim resEnt As SearchResult

For Each resEnt In mySearcher.Find All

Try

Dim tmpID As String = Mid(resEnt.GetD irectoryEntry.N ame.ToString, 4)

If Mid(tmpID, 1, 2) = "L1" Then

Dim rwComputer As DataRow

rwComputer = dtComputers.New Row

rwComputer("Com puter Name") =
(Mid((resEnt.Ge tDirectoryEntry ().Name.ToStrin g), 4))

dtComputers.Row s.Add(rwCompute r)

End If

tsStatus.Text = "Computers Loaded..."

cboDomainComute rs.DataSource = dtComputers

cboDomainComute rs.DisplayMembe r = "Computer Name"

Catch ex As Exception

End Try

Next

Catch ex As Exception

End Try

End Sub

John,
Doh! You don't need the delegate or the Invoke, the "beauty" of the
background work thread is that it handles the communication between both
threads for you.

Something like:

'called from form load

Protected Overrides Sub OnLoad(ByVal e As System.EventArg s)
MyBase.OnLoad(e )
tsStatus.Text = "Loading Computers. Please wait..."
bgLoadComputers .RunWorkerAsync ()
End Sub

'sub that does the work

Private Sub bgLoadComputers _DoWork(ByVal sender As System.Object, ByVal
e As System.Componen tModel.DoWorkEv entArgs) Handles bgLoadComputers .DoWork
System.Threadin g.Thread.Sleep( TimeSpan.FromSe conds(2))
e.Result = LoadComputerDro pDown()
End Sub

Private Function LoadComputerDro pDown() As DataTable
Dim dtComputers As New DataTable("Comp uters")
dtComputers.Col umns.Add("Compu ter Name", GetType(String) )
'get the computers on the domain
Dim enTry As DirectoryEntry = New DirectoryEntry( "LDAP://[MYDOMAIN])
Dim mySearcher As DirectorySearch er = New DirectorySearch er(enTry)
mySearcher.Filt er = ("(objectClass= Computer)")
Dim resEnt As SearchResult
For Each resEnt In mySearcher.Find All
Dim tmpID As String =
Mid(resEnt.GetD irectoryEntry.N ame.ToString, 4)
If Mid(tmpID, 1, 2) = "L1" Then
Dim rwComputer As DataRow
rwComputer = dtComputers.New Row
rwComputer("Com puter Name") =
(Mid((resEnt.Ge tDirectoryEntry ().Name.ToStrin g), 4))
dtComputers.Row s.Add(rwCompute r)
End If
Next
Return dtComputers
End Function

Private Sub bgLoadComputers _RunWorkerCompl eted(ByVal sender As Object,
ByVal e As System.Componen tModel.RunWorke rCompletedEvent Args) Handles
bgLoadComputers .RunWorkerCompl eted
If e.Error Is Nothing Then
tsStatus.Text = "Computers Loaded..."
cboDomainComute rs.DataSource = e.Result
cboDomainComute rs.DisplayMembe r = "Computer Name"
Else
MessageBox.Show (e.Error.ToStri ng(), Application.Pro ductName,
MessageBoxButto ns.OK, MessageBoxIcon. Error)
End If
End Sub
--
Hope this helps
Jay B. Harlow [MVP - Outlook]
..NET Application Architect, Enthusiast, & Evangelist
T.S. Bradley - http://www.tsbradley.net

"John Wright" <ri**********@n otmail.comwrote in message
news:%2******** ********@TK2MSF TNGP05.phx.gbl. ..

>I have a background worker thread that scans the network listing computers
that are connected. I have a delegate that I call that invokes a procdure
that loads a dataset with computer names and then attaches it to a
dropdown. When I run it, my UI freezes until it completes. Any thoughts on
how to do this without freezing the UI?

John
Code

'General Declaration

Private Delegate Sub LoadComputerDel egate()

'called from form load

bgLoadComputers .RunWorkerAsync ()

'sub that does the work

Private Sub bgLoadComputers _DoWork(ByVal sender As System.Object, ByVal e
As System.Componen tModel.DoWorkEv entArgs) Handles bgLoadComputers .DoWork

tsStatus.Text = "Loading Computers. Please wait..."

System.Threadin g.Thread.Sleep( TimeSpan.FromSe conds(2))

Invoke(New LoadComputerDel egate(AddressOf LoadComputerDro pDown))

End Sub

Private Sub LoadComputerDro pDown()

'get the computers on the domain

Try

Dim enTry As DirectoryEntry = New DirectoryEntry( LDAP://[MYDOMAIN])

Dim mySearcher As DirectorySearch er = New DirectorySearch er(enTry)

mySearcher.Filt er = ("(objectClass= Computer)")

Dim resEnt As SearchResult

For Each resEnt In mySearcher.Find All

Try

Dim tmpID As String = Mid(resEnt.GetD irectoryEntry.N ame.ToString, 4)

If Mid(tmpID, 1, 2) = "L1" Then

Dim rwComputer As DataRow

rwComputer = dtComputers.New Row

rwComputer("Com puter Name") =
(Mid((resEnt.Ge tDirectoryEntry ().Name.ToStrin g), 4))

dtComputers.Row s.Add(rwCompute r)

End If

tsStatus.Text = "Computers Loaded..."

cboDomainComute rs.DataSource = dtComputers

cboDomainComute rs.DisplayMembe r = "Computer Name"

Catch ex As Exception

End Try

Next

Catch ex As Exception

End Try

End Sub

Excellent. This works great. Thanks.

John
"Jay B. Harlow [MVP - Outlook]" <Ja************ @tsbradley.netw rote in
message news:CD******** *************** ***********@mic rosoft.com...

John,
Doh! You don't need the delegate or the Invoke, the "beauty" of the
background work thread is that it handles the communication between both
threads for you.

Something like:

'called from form load

Protected Overrides Sub OnLoad(ByVal e As System.EventArg s)
MyBase.OnLoad(e )
tsStatus.Text = "Loading Computers. Please wait..."
bgLoadComputers .RunWorkerAsync ()
End Sub

'sub that does the work

Private Sub bgLoadComputers _DoWork(ByVal sender As System.Object, ByVal
e As System.Componen tModel.DoWorkEv entArgs) Handles bgLoadComputers .DoWork
System.Threadin g.Thread.Sleep( TimeSpan.FromSe conds(2))
e.Result = LoadComputerDro pDown()
End Sub

Private Function LoadComputerDro pDown() As DataTable
Dim dtComputers As New DataTable("Comp uters")
dtComputers.Col umns.Add("Compu ter Name", GetType(String) )
'get the computers on the domain
Dim enTry As DirectoryEntry = New
DirectoryEntry( "LDAP://[MYDOMAIN])
Dim mySearcher As DirectorySearch er = New DirectorySearch er(enTry)
mySearcher.Filt er = ("(objectClass= Computer)")
Dim resEnt As SearchResult
For Each resEnt In mySearcher.Find All
Dim tmpID As String =
Mid(resEnt.GetD irectoryEntry.N ame.ToString, 4)
If Mid(tmpID, 1, 2) = "L1" Then
Dim rwComputer As DataRow
rwComputer = dtComputers.New Row
rwComputer("Com puter Name") =
(Mid((resEnt.Ge tDirectoryEntry ().Name.ToStrin g), 4))
dtComputers.Row s.Add(rwCompute r)
End If
Next
Return dtComputers
End Function

Private Sub bgLoadComputers _RunWorkerCompl eted(ByVal sender As Object,
ByVal e As System.Componen tModel.RunWorke rCompletedEvent Args) Handles
bgLoadComputers .RunWorkerCompl eted
If e.Error Is Nothing Then
tsStatus.Text = "Computers Loaded..."
cboDomainComute rs.DataSource = e.Result
cboDomainComute rs.DisplayMembe r = "Computer Name"
Else
MessageBox.Show (e.Error.ToStri ng(), Application.Pro ductName,
MessageBoxButto ns.OK, MessageBoxIcon. Error)
End If
End Sub
--
Hope this helps
Jay B. Harlow [MVP - Outlook]
.NET Application Architect, Enthusiast, & Evangelist
T.S. Bradley - http://www.tsbradley.net

"John Wright" <ri**********@n otmail.comwrote in message
news:%2******** ********@TK2MSF TNGP05.phx.gbl. ..

>>I have a background worker thread that scans the network listing computers
that are connected. I have a delegate that I call that invokes a procdure
that loads a dataset with computer names and then attaches it to a
dropdown. When I run it, my UI freezes until it completes. Any thoughts
on how to do this without freezing the UI?

John
Code

'General Declaration

Private Delegate Sub LoadComputerDel egate()

'called from form load

bgLoadComputer s.RunWorkerAsyn c()

'sub that does the work

Private Sub bgLoadComputers _DoWork(ByVal sender As System.Object, ByVal e
As System.Componen tModel.DoWorkEv entArgs) Handles bgLoadComputers .DoWork

tsStatus.Tex t = "Loading Computers. Please wait..."

System.Threadi ng.Thread.Sleep (TimeSpan.FromS econds(2))

Invoke(New LoadComputerDel egate(AddressOf LoadComputerDro pDown))

End Sub

Private Sub LoadComputerDro pDown()

'get the computers on the domain

Try

Dim enTry As DirectoryEntry = New DirectoryEntry( LDAP://[MYDOMAIN])

Dim mySearcher As DirectorySearch er = New DirectorySearch er(enTry)

mySearcher.Fil ter = ("(objectClass= Computer)")

Dim resEnt As SearchResult

For Each resEnt In mySearcher.Find All

Try

Dim tmpID As String = Mid(resEnt.GetD irectoryEntry.N ame.ToString, 4)

If Mid(tmpID, 1, 2) = "L1" Then

Dim rwComputer As DataRow

rwComputer = dtComputers.New Row

rwComputer("Co mputer Name") =
(Mid((resEnt.G etDirectoryEntr y().Name.ToStri ng), 4))

dtComputers.Ro ws.Add(rwComput er)

End If

tsStatus.Tex t = "Computers Loaded..."

cboDomainComut ers.DataSource = dtComputers

cboDomainComut ers.DisplayMemb er = "Computer Name"

Catch ex As Exception

End Try

Next

Catch ex As Exception

End Try

End Sub