File I/O to read a specific line

Question

Hey guys,

In need of help.  I need to read a line from a .ini file (specifically the 4th line).  What it is, is a path to a database which I want to implement as the connection file in my vb window forum --> crystal reports so crystal viewer can pull the data from that database.

[CONFIG]
ReportDirectory=E:\appdata\
MainframePortNumber=1111
ClientsDB=E:\appdata\clients.mdb
ProviderDB=E:\appdata\provider.mdb


So I need VB to read the 4th line and it has to pull E:\appdata\clients.mdb and set it as the database path for crystal reports.

Can anyone shed some light :) thanks.

Answer 1

As a answer on you question how to read the 4th line:

Dim reader As StreamReader =  New StreamReader("c:\myinifile.ini")   Dim line As String =  Nothing Dim lineCounter As Integer =  0 While Not(line = reader.ReadLine()) Is Nothing     lineCounter = lineCounter + 1       If lineCounter = 4 Then         ' TODO: Handle the data from line 4.     End If End While '---------------------------------------------------------------- ' Converted from C# to VB .NET using CSharpToVBConverter(1.2). ' Developed by: Kamal Patel (http://www.KamalPatel.net) '----------------------------------------------------------------

But you can use a Ini helper class, that makes live easy to work with INI file. You can find one on codeproject, here.

Answer 2

oh sorry, I forgot to mention im using Visual Studio .NET 2003 not 2005.

I dont think StreamReader can be used in 2003.

Answer 3

StreamReader can be used in 2003.

Answer 4

You must import System.IO, i think you forgot to do that. Let us know if it worked out for you!

Answer 5

^thanks man, that did the trick.

But ran into a small problem, got the following error:

" 'Is' requires operands that have reference types, but this operand has the value type 'Boolean'."

I'm getting that error for the following line:

While Not (line = reader.ReadLine()) Is Nothing

And also do you know how I can chop the first part "ClientsDB=" and only get the path ?  Im sorry, I'm really new to VB, last time I programmed in VB was oh about 6 years ago.  I'm currently doing C and C++.

Thanks for all the help! you guys are awesome.

Answer 6

ok wait, I've been playing around with the code, but stupid me, I didnt catch this before, how is the code advancing ?  I mean hows the program going to know which line is line 4.  all the counter is doing is advancing but the cursor (in the file) is still at line 1.  So when i print the result I get the first line.

Here is the code im using

[code]
        Dim reader As StreamReader = New StreamReader("c:\C4\CONTACT.ini")
        Dim writer As StreamWriter = New StreamWriter("c:\test.txt")
        Dim Path As String = Nothing
        Dim lineCounter As Integer = 0
        While (Path) Is Nothing
            lineCounter = lineCounter + 1
            If lineCounter = 4 Then
                Path = reader.ReadLine()
                writer.WriteLine(Path)
            End If
        End While
        reader.Close()
        writer.Close()
    End Sub
[/code]

Answer 7

Dim rdr As New System.IO.StreamReader("C:\MyFile.txt")
Dim buffer As String = ""
Dim lineNumber As Integer = 0

While Not rdr.EndOfStream

    buffer = rdr.ReadLine()
    lineNumber += 1

    If lineNumber = 4 Then
        Debug.WriteLine(buffer.Substring(buffer.IndexOf("=") + 1))
        Exit While
    End If

End While
rdr.Close()

Answer 8

THANK YOU! that did it.  Well I took the buffer part and it worked.  Now I just have to truncate which I believe I can use String.Split or Readline.Split("=").

Private Sub MenuItem4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MenuItem4.Click
        Dim reader As StreamReader = New StreamReader("c:\Contact4\CONTACT.ini")
        Dim writer As StreamWriter = New StreamWriter("c:\test.txt")
        Dim Path As String = Nothing
        Dim Buffer As String = ""
        Dim lineCounter As Integer = 0
        While (Path) Is Nothing
            Buffer = reader.ReadLine()
            lineCounter = lineCounter + 1
            If lineCounter = 3 Then
                Path = reader.ReadLine()
                writer.WriteLine(Path)
            End If
        End While
        reader.Close()
        writer.Close()
    End Sub

Answer 9

In the example code I provided, the Debug.WriteLine part, that will output only the characters after the first = in the string. Thus removing your ClientDB=.

Good Luck,

-Joe

Answer 10

Hey guys, thanks for everything.  all worked out good!  Final code is below with the splitting characters.  I'm pretty sure you can combine path and path2 togheter but I like splitting it for ease of reading.

        Dim reader As StreamReader = New StreamReader("c:\Contact4\CONTACT.ini")
        Dim writer As StreamWriter = New StreamWriter("c:\test.txt")
        Dim Path As String = Nothing
        Dim Path2() As String
        Dim Buffer As String = ""
        Dim lineCounter As Integer = 0
        While (Path) Is Nothing
            Buffer = reader.ReadLine()
            lineCounter = lineCounter + 1
            If lineCounter = 3 Then
                Path = reader.ReadLine()
                Path2 = Strings.Split(Path, "=")
                writer.WriteLine(Path2(1))
            End If
        End While
        reader.Close()
        writer.Close()

Answer 11

Glad you got it working. You should also be aware that this solution is not flexible at all. Should your ini file change in the future, you have hard coded in the location of that particular item, thus breaking your code. A better solution would be to abandon the ini file in favor of an xml file that is stored in the application data directory.

-Joe

Answer 12

Problem with that is I cannot change the other application.  The ini file is a configuration file for another application and the installation is universal and I have no control over so I cannot add an xml file into the installer of that program.  (its a program used by the whole province).

And my reporting application will have to use the contact.ini file and only that.  so its not too bad as the default install path is the same and the construction of the ini file is same on every machine its installed on.

Answer 13

and maybe somone here can help me with another problem aswell...

http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=253718&SiteID=1

thanks

Answer 14

Since the file is a standard INI file (it appears to be), rather than reading it as a file, use the Win32 API to read and write the INI settings (Get: then, it doesn't matter what changes are made to the INI file. I Don't have .NET code to do this, yet (only in VB6, currently), as I haven't needed it. I wouldn't anticipate any issues, though.

The APIs are called GetPrivateProfileString and WritePrivateProfileString, if you want to look them up.