Public Sub MyReader(ByVal strCommand As String)
        Dim change As New delProgress(AddressOf progressChange)
 
        Dim strConnection As String
        strConnection = "Data Source=mySV; "
        strConnection += "Initial Catalog=myDB;"
        strConnection += "User Id=Me; Password=myPW"
        Dim Connection As New SqlClient.SqlConnection(strConnection)
 
       Using Connection
            Dim cmdDirtyRead As New System.Data.SqlClient.SqlCommand("SET" & _
              "TRANSACTION ISOLATION LEVEL READ UNCOMMITTED", Connection)
 
            Dim command As SqlCommand = New SqlCommand(strCommand, Connection)
            Connection.Open()
            cmdDirtyRead.ExecuteNonQuery()
            Dim reader As SqlDataReader = command.ExecuteReader()
 
            Dim intC As Double
            If reader.HasRows Then
                Do While reader.Read()
                    If intC = 100 Then
                        intC = 0
                    End If
                    intC += 1
                    'irgendwas lesen
                    Me.Invoke(change, intC, "Lese Daten!")
                Loop
            Else
                Label1.Text = "keine weiteren Einträge!"
            End If
 
            reader.Close()
        End Using
 
    End Sub

    Delegate Sub delProgress(ByVal value As Double, ByVal text As String)
 
    Public Sub progressChange(ByVal value As Double, ByVal text As String)
        If value > 100 Then
            value = 1
        End If
        ProgressBar1.Value = value
        Label1.Text = text
    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button1.Click
        Dim MyThread3 As New Threading.Thread(AddressOf MyReader)
        Dim strCommand As String = "SELECT ..."
        If MyThread3.IsAlive Then
            MessageBox.Show("Die Aktion wird bereits ausgeführt")
        Else
            MyThread3.Start(strCommand)
        End If
 
    End Sub