Exctract TNS Names from TNSNAMES.ORA using Visual Basic 6 (VB6)

To extract TNS Names from tnsnames.ora file you can use below listed function Read_Tns_File.
This function extract TNS Names and add them into ComboBox(cmbTns).

Private Sub Read_Tns_File(strFileName As String, cmbTns As ComboBox)
    On Error GoTo FileErrHandler ' Jump if an error occurs
    Dim intTnsFile As Integer
    Dim strData As String
    Dim bolTnsStart As Boolean
    Dim bolBracketStart As Boolean
    Dim intBracketCounter As Integer
    intBracketCounter = 0
    intTnsFile = FreeFile
    ' open tns file
    Open strFileName For Input As intTnsFile
    ' read tns file
    Do Until (EOF(intTnsFile))
        Line Input #intTnsFile, strData
        ' checking for remarks
        If Left(LTrim(strData), 1) <> "#" And LTrim(strData) <> "" Then
        If Not bolTnsStart Then
            Dim intEqualPos As Integer
            Dim intTnsStringSingle As String
            
            intEqualPos = InStr(strData, "=")
            
            If intEqualPos = 0 Then
              intTnsStringSingle = strData
            Else
              intTnsStringSingle = Mid(strData, 1, intEqualPos - 1)
            End If

            cmbTns.AddItem (Trim(intTnsStringSingle))
            bolTnsStart = True
        End If

        If bolTnsStart And InStr(strData, "(") > 0 Then
          bolBracketStart = True
        End If

        intBracketCounter = intBracketCounter + (Len(strData) - Len(Replace(strData, "(", "")))
        intBracketCounter = intBracketCounter - (Len(strData) - Len(Replace(strData, ")", "")))
      End If

      If intBracketCounter = 0 And bolBracketStart Then
        bolBracketStart = False
        bolTnsStart = False
      End If
    Loop
    Close intTnsFile
    Exit Sub
FileErrHandler:
    ' if any error occurs while file handling exit the procedure
    Close intTnsFile
    Exit Sub
End Sub