Multithreading Safe Calls not populating comboboxes vb.net - vb.net

Question

just curious on what im doing wrong here, the principle should work. Can anyone give me a hand?
The Code runs fine, but seems to not add them into my comboboxes
normal thread start like so
t1 = New Thread(New ThreadStart(AddressOf GetNewClientData))
t1.Start()
data is not empty or null... :)
Function GetNewClientData()
Try
Dim con As New SqlConnection
Dim myConString As String = My.Settings.ConString
Dim objcommand As SqlCommand = New SqlCommand
With objcommand
.Connection = con
Dim cmdText As String = "SELECT distinct Applicant,Client,Market,Project from AAClient order by Client"
.CommandText = cmdText
End With
con.ConnectionString = myConString
con.Open()
Using readerObj As SqlClient.SqlDataReader = objcommand.ExecuteReader
'This will loop through all returned records
While readerObj.Read
addClientInvoke(readerObj("Client").ToString)
addApplicantInvoke(readerObj("Client").ToString)
addMarketInvoke(readerObj("Client").ToString)
addProjectInvoke(readerObj("Client").ToString)
End While
End Using
con.Close()
Catch ex As Exception
End Try
Return Nothing
End Function
Delegate Sub addApplicant(s As String)
Sub addApplicantInvoke(ByVal s As String)
If CreateNewSite.cbApplicant.InvokeRequired Then
Dim d As New addApplicant(AddressOf addApplicantInvoke)
CreateNewSite.cbApplicant.Invoke(d, New Object() {s})
Else
CreateNewSite.cbApplicant.Items.Add(s)
End If
End Sub
Delegate Sub addClient(s As String)
Sub addClientInvoke(ByVal s As String)
If CreateNewSite.cbClient.InvokeRequired Then
Dim d As New addClient(AddressOf addClientInvoke)
CreateNewSite.cbClient.Invoke(d, New Object() {s})
Else
CreateNewSite.cbClient.Items.Add(s)
End If
End Sub
Delegate Sub addMarket(s As String)
Sub addMarketInvoke(ByVal s As String)
If CreateNewSite.cbMarket.InvokeRequired Then
Dim d As New addMarket(AddressOf addMarketInvoke)
CreateNewSite.cbMarket.Invoke(d, New Object() {s})
Else
CreateNewSite.cbMarket.Items.Add(s)
End If
End Sub
Delegate Sub addProject(s As String)
Sub addProjectInvoke(ByVal s As String)
If CreateNewSite.cbProject.InvokeRequired Then
Dim d As New addProject(AddressOf addProjectInvoke)
CreateNewSite.cbProject.Invoke(d, New Object() {s})
Else
CreateNewSite.cbProject.Items.Add(s)
End If
End Sub
possibly how i'm calling the delegate??
any help is appreciated
**** thanks to #jods here is the working code with one of the invoke methods****
starting thread in another modul
t1 = New Thread(New ParameterizedThreadStart(AddressOf GetNewClientData))
t1.Start(Me)
Code within the Modul
Function GetNewClientData(ByVal oldForm As CreateNewSite)
Try
Dim con As New SqlConnection
Dim myConString As String = My.Settings.ConString
Dim objcommand As SqlCommand = New SqlCommand
With objcommand
.Connection = con
Dim cmdText As String = "SELECT distinct Applicant,Client,Market,Project from AAClient order by Client"
.CommandText = cmdText
End With
con.ConnectionString = myConString
con.Open()
Using readerObj As SqlClient.SqlDataReader = objcommand.ExecuteReader
'This will loop through all returned records
While readerObj.Read
addApplicantInvoke(readerObj("Applicant").ToString, oldForm)
addClientInvoke(readerObj("Client").ToString)
addMarketInvoke(readerObj("Market").ToString)
addProjectInvoke(readerObj("Project").ToString)
End While
End Using
con.Close()
Catch ex As Exception
MsgBox(ex)
End Try
Return Nothing
End Function
Delegate Sub addApplicant(s As String, oldform As CreateNewSite)
Sub addApplicantInvoke(ByVal s As String, ByVal oldform As CreateNewSite)
If oldform.InvokeRequired Then
Dim d As New addApplicant(AddressOf addApplicantInvoke)
oldform.cbApplicant.Invoke(d, New Object() {s, oldform})
Else
oldform.cbApplicant.Items.Add(s)
End If
End Sub

Answer 1

The problem is CreateNewSite.cbProject. CreateNewSite is not your form instance. It's a nifty :p VB.NET feature called the default form instance:
VB has a concept of "Default Form Instances". For every Form in the application's namespace, there will be a default instance created in the My namespace under the Forms property.
You need to pass the correct form instance (i.e. 'Me' / 'this') to your background thread.