[Débutant] comment imprimer un textbox multiline

bonjour à tous
je veut imprimer le contenu d'un textbox multiline mon probléme est que sa imprime tout sur une méme ligne si quelqu'un peu m'aidé svp
voici une partie de mon code
Code:
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   Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        ' autorise le choix de la page d'impression
        PrintDialog1.AllowSomePages = True
        ' montre le bouton d'aide
        PrintDialog1.ShowHelp = True
        ' Fixe les propriétés du documents  (impératif)
        PrintDialog1.Document = docToPrint
        Dim result As DialogResult = PrintDialog1.ShowDialog()
        docToPrint.DefaultPageSettings.Landscape = True
        ' Si le résultat est bon on imprime
        If (result = Windows.Forms.DialogResult.OK) Then
            docToPrint.Print()
        End If    
    End Sub
 Private Sub document_PrintPage(ByVal sender As Object, ByVal e As System.Drawing.Printing.PrintPageEventArgs) Handles docToPrint.PrintPage
        'champs de saisie
 lab1 As String = Label1.Text
 
        Dim printFont As New System.Drawing.Font("Arial", 10, System.Drawing.FontStyle.Regular)
        'rrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr
        Dim strText As String = TextBox1.Text
        Dim myreader = New StringReader(strText)
        Dim linesPerPage As Single = 0
        Dim yPosition As Single = 0
        Dim count As Integer = 0
        Dim leftMargin As Single = e.MarginBounds.Left
        Dim topMargin As Single = e.MarginBounds.Top
        Dim line As String = Nothing
        Dim printFont1 As Font = TextBox1.Font
        Dim myBrush As New SolidBrush(Color.Black)
        linesPerPage = e.MarginBounds.Height / printFont.GetHeight(e.Graphics)
        While count < linesPerPage
            line = myreader.ReadLine()
            If (line Is Nothing) Then
                Exit While
            Else
                yPosition = topMargin + count * printFont.GetHeight(e.Graphics)
 
                e.Graphics.DrawString(line, printFont, myBrush, leftMargin, yPosition, New StringFormat())
 
                count += 1
                If count >= linesPerPage Then
                    e.HasMorePages = True
                    count = 0
                End If
            End If
        End While
        e.HasMorePages = False
        myBrush.Dispose()
    'champ de saisie
        e.Graphics.DrawString(lab1, printFont, System.Drawing.Brushes.Black, 300, 80)
    End Sub