Регулярные выражения для выделения нескольких строк

Public Class Form1
    Private aaa As String = "aaa"
    Private bbb As String = "bbb"
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        MsgBox(aaa + vbCrLf + bbb)
        Close()
    End Sub
End Class

Public Class Form1
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim a As New List(Of String)
        Pars(TextBox1.Text, "Public Class", vbCrLf + "End Class", a)
        For i = 0 To a.Count - 1
            MsgBox(a(i))
        Next
    End Sub
    Public Sub Pars(ByVal source As String, ByVal strStart As String, ByVal strEnd As String, ByRef Result As List(Of String), Optional ByVal startPosition As Integer = 0)
        Dim indStart As Integer = source.IndexOf(strStart, startPosition)
        Dim indEnd As Integer = source.IndexOf(strEnd, startPosition)
        If indStart <> -1 AndAlso indEnd <> -1 Then
 
            Result.Add(source.Substring(indStart, indEnd + strEnd.Length - indStart))
            Pars(source, strStart, strEnd, Result, indEnd + strEnd.Length)
        End If
    End Sub
 
End Class

Public Class Form1
    Private aaa As String = "aaa"
    Private bbb As String = "bbb"
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        MsgBox(aaa + vbCrLf + bbb)
        Close()
    End Sub
End Class
 
Public Class Form2
    Private aaa As String = "aaa"
    Private bbb As String = "bbb"
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        MsgBox(aaa + vbCrLf + bbb)
        Close()
    End Sub
End Class

Dim Mat As MatchCollection
Mat = Regex.Matches(textbox, ".*?Class .+?End Class", RegexOptions.Multiline Or RegexOptions.Singleline)