Zitat:

Du kannst aber zB die Connection in der Hauptanwendung anlegen und an BGW mit der RunWorkerAsync() Methode übergeben.

Zitat:

Du kannst nicht direkt auf Steuerelemente zugreifen.

Imports System.ComponentModel
 
Public Class Form1
 
    Private WithEvents bgw As New BackgroundWorker
    Private Delegate Function GetTextBoxContentDelegate() As String
 
    Private Function GetTextBoxContent() As String
        If Me.InvokeRequired Then
            Return Me.Invoke(New GetTextBoxContentDelegate(AddressOf _
              GetTextBoxContent))
        Else
            Return Me.TextBox1.Text
        End If
    End Function
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button1.Click
        bgw.RunWorkerAsync()
    End Sub
 
    Private Sub bgw_DoWork(ByVal sender As Object, ByVal e As _
      System.ComponentModel.DoWorkEventArgs) Handles bgw.DoWork
        MsgBox(GetTextBoxContent)
    End Sub
 
End Class