Public Class Form1
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        PrintDocument1.Print()
    End Sub
    Private Sub stampa(ByVal sender As System.Object, ByVal e As System.Drawing.Printing.PrintPageEventArgs) Handles PrintDocument1.PrintPage
        Dim a As String
        'Replace sostituisce le parole chiave nello Zpl con quelle del form
        a = TextBox1.Text.Replace("9testo9", TextBox2.Text).Replace("9numeroetic9", NumericUpDown1.Value)
        e.Graphics.DrawString(a, Font, Brushes.Black, 0, 0)
    End Sub
End Class