Private Sub CreateInvoiceQuery()
        Dim InsertCom = Me.InvoiceDataAdapterX.Adapter.InsertCommand
        If invoice_id = Nothing Then
            InsertCom.CommandText = "INSERT INTO `invoice` (`date_created`, `customerid`) VALUES (?, ?)"

            InsertCom.Parameters(0).Value = CType(Me.DateTimePicker1.Value, Date)
            InsertCom.Parameters(1).Value = 1
            InsertCom.Connection.Open()
            InsertCom.ExecuteNonQuery()
            InsertCom.CommandText = "SELECT @@IDENTITY"
            invoice_id = InsertCom.ExecuteScalar
            NoInvoiceTextBox.Text = invoice_id.ToString("D6")
            InsertCom.Connection.Close()
            InsertCom.Dispose()
        End If
        Debug.WriteLine(invoice_id.ToString)
    End Sub