จะให้โปรแกรมอ่าน textfile โดยสามารถกำหนดคำที่เราต้องการให้อ่านได้

dim A As Boolean
dim B As Boolean
if source.IndexOf("คำค้น1") < 0 
then A = False
else A = True
end if

if source.IndexOf("คำค้น2") < 0 
then B = False
else B = True
end if

if (A=True) and (B=True)
then
  ....
end if 

Dim fileinfo As New System.IO.FileStream("D:\CountOutput.txt", IO.FileMode.Open)
        Dim Reader As New System.IO.StreamReader(fileinfo)
        Dim List As New List(Of String)
        Do While Reader.Peek > 0
            List.Add(Reader.ReadLine)
        Loop

        Dim Array1 As String() = List.ToArray
        fileinfo.Close()
        Reader.Close()

        fileinfo = New System.IO.FileStream("D:\CountOutput.txt", IO.FileMode.Open)
        Reader = New System.IO.StreamReader(fileinfo)

        Dim sArray As String()
        Dim Index As Integer
        Do While Reader.Peek > 0
            ReDim Preserve sArray(Index)
            sArray(Index) = Reader.ReadLine
            Index += 1
        Loop

        Dim i As Integer
        For i = 0 To UBound(sArray)
            Label20.Visible = True
            Label20.Text = sArray(i)
        Next

        fileinfo.Close()
        Reader.Close()
    End Sub

Dim	fileinfo = New System.IO.FileStream("D:\CountOutput.txt", IO.FileMode.Open)
Dim	Reader = New System.IO.StreamReader(fileinfo)
Dim sArray As String()
Dim Index As Integer
Dim tmp As String
Do While Reader.Peek > 0
	tmp = Reader.ReadLine;
	if tmp.IndexOf("คำค้น1") >= 0 
	then
		begin
			ReDim Preserve sArray(Index)
			sArray(Index) = tmp
			Index += 1
		end
	end if
Loop

Dim i As Integer
Dim c As Integer = sArray.Length-1;
For i = 0 To c
	Label20.Visible = True
	Label20.Text = sArray(i)
Next

fileinfo.Close()
Reader.Close()

Dim strRegex as String = "(สแกนยังไม่ครบ\s?Box\s?G\d{4}/\d{5}\s?\d{2}/\d{3})" //หรือ "(.*?Box\s?G\d{4}/\d{5}\s?\d{2}/\d{3})" 
Dim myRegex As New Regex(strRegex, RegexOptions.None)
Dim strTargetString As String = My.Computer.FileSystem.ReadAllText("D:\CountOutput.txt",System.Text.Encoding.UTF32)

For Each myMatch As Match In myRegex.Matches(strTargetString)
      messagebox.show(myMatch.Group[1].Value)
Next