Public Sub CheckFiles(ByVal TxtToFind As String, ByVal Path As String, ByRef sb As System.Text.StringBuilder, ByVal Filter As String)
        For Each file As String In Directory.GetFiles(Path, Filter)
            Dim txt As String = ReadFile(file)
            If txt.IndexOf(TxtToFind) <> -1 Then
                sb.AppendLine(file)
            End If
        Next
        For Each dir As String In Directory.GetDirectories(Path)
            CheckFiles(TxtToFind, dir, sb, Filter)
        Next
    End Sub