Public Class Form1

    Private Function SplitSentences(ByVal sSourceText As String) As ArrayList

        ' create a local string variable
        ' set to contain the string passed it
        Dim sTemp As String = sSourceText

        ' create the array list that will
        ' be used to hold the sentences
        Dim al As New ArrayList()
        Dim Regex As String


        ' split the sentences with a regular expression
        Dim RegexSentenceParse As String() = _
            Regex.Split(sTemp, "(?<=['""A-Za-z0-9][\.\!\?])\s+(?=[A-Z])")

        ' loop the sentences
        Dim i As Integer = 0
        For i = 0 To RegexSentenceParse.Length - 1
            ' clean up the sentence one more time, trim it,
            ' and add it to the array list
            Dim sSingleSentence As String = _
            RegexSentenceParse(i).Replace(Environment.NewLine, String.Empty)
            al.Add(sSingleSentence.Trim())
        Next

    End Function

    Private Sub ListBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ListBox1.SelectedIndexChanged
        ListBox1.ClearSelected()
    End Sub
End Class