Выделить строку в RichTextBox

 Private Sub RichTextBox1_TextChanged(sender As Object, e As EventArgs) Handles RichTextBox1.TextChanged
        Dim Words_dont_come_easy As String = "INFO:"
        Dim allIp As MatchCollection = Regex.Matches(RichTextBox1.Text, Words_dont_come_easy)
        For Each ip As Match In allIp
            RichTextBox1.SelectionStart = ip.Index
            RichTextBox1.SelectionLength = ip.Length
            RichTextBox1.SelectionBackColor = Color.DarkGreen
            RichTextBox1.SelectionColor = Color.Yellow
            RichTextBox1.SelectionFont = New Font(RichTextBox1.Text, 10, FontStyle.Bold)
        Next
        RichTextBox1.ScrollToCaret()
End Sub

 Private Sub RichTextBox1_TextChanged(sender As Object, e As EventArgs) Handles RichTextBox1.TextChanged
        Dim Words_dont_come_easy As String = "INFO:"
        Dim allIp As MatchCollection = Regex.Matches(RichTextBox1.Text, Words_dont_come_easy)
        For Each ip As Match In allIp
            RichTextBox1.SelectionStart = ip.Index
            RichTextBox1.SelectionLength = ip.Length
            RichTextBox1.SelectionBackColor = Color.DarkGreen
            RichTextBox1.SelectionColor = Color.Yellow
            RichTextBox1.SelectionFont = New Font(RichTextBox1.Text, 10, FontStyle.Bold)
        Next
        RichTextBox1.ScrollToCaret()
        Dim numChr As Integer = RichTextBox1.SelectionStart
        Dim nn, nRow As Integer
        For i = 0 To RichTextBox1.Lines.Length - 1
            nn += RichTextBox1.Lines(i).Length
            If numChr < nn Then
                nRow = i
                Exit For
            End If
        Next
        TextBox2.Text = nRow
    End Sub

Private Sub Button7_Click(sender As System.Object, e As System.EventArgs) Handles Button7.Click
    Dim nn As Integer = NumericUpDown1.Value
    If nn > RTB1.Lines.Length - 1 Then Exit Sub
    Dim zz As Integer
    If nn > 0 Then
        For i = 0 To nn - 1
            zz += RTB1.Lines(i).Length + 1
        Next
    End If
    RTB1.SelectionStart = zz
    RTB1.SelectionLength = RTB1.Lines(nn).Length
    RTB1.Select()
End Sub

Public Function Выделение()
Dim nn As Integer = NumericUpDown1.Value
    If nn > RTB1.Lines.Length - 1 Then Exit Sub
    Dim zz As Integer
    If nn > 0 Then
        For i = 0 To nn - 1
            zz += RTB1.Lines(i).Length + 1
        Next
    End If
    RTB1.SelectionStart = zz
    RTB1.SelectionLength = RTB1.Lines(nn).Length
    RTB1.Select()
Return Me
    End Function

Выделение()