[RESOLVED] Stream i/o issue

Hi,

Just starting up on VB 2008 Express (.NET).
Trying to write to and read from a file.
It runs without errors, but the messagebox only shows the 'OK' button, not the contents of the file as I want. I thought that maybe I have to rewind the file before reading, but AFAICS there is no 'StreamRead.Rewind' or Reset or something.
What am I missing, please?

Code:

---

Imports System.IO

Public Class ArrayTest

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        Dim strId As String
        Dim intPeriod As Int16
        Dim intValue As Int16

        Dim DataFileName As New String("C:\Documents and Settings\Janneman\Bureaublad\bTFiletest.txt")
        Dim objDataFile As New FileStream(DataFileName, FileMode.Create, FileAccess.ReadWrite, FileShare.ReadWrite)
        Dim objDataWriter As New StreamWriter(objDataFile)

        strId = "Bias"
        intPeriod = 25
        intValue = 35

        objDataWriter.Write(strId & CStr(intPeriod) & CStr(intValue))

        If File.Exists(DataFileName) Then
            Dim objDataReader As New StreamReader(objDataFile)
            MessageBox.Show(objDataReader.ReadToEnd)
        Else : MessageBox.Show("File doesn't exist")
        End If

        objDataWriter.Close()
        objDataFile.Close()


    End Sub
End Class

---

Jan Didden

I didnt test it but I think this will work;

Code:

---

        Dim strId As String = "Bias"
        Dim intPeriod As Int16 = 25
        Dim intValue As Int16 = 35
        Dim DataFileName As String = "C:\Documents and Settings\Janneman\Bureaublad\bTFiletest.txt"

        Dim objDataWriter As New System.IO.StreamWriter(DataFileName)
        objDataWriter.Write(strId & CStr(intPeriod) & CStr(intValue))
        objDataWriter.Close()

        If System.IO.File.Exists(DataFileName) Then
            Dim objDataReader As New System.IO.StreamReader(DataFileName)
            MessageBox.Show(objDataReader.ReadToEnd)
            objDataReader.Close()
        Else
            MessageBox.Show("File doesn't exist")
        End If

---

Hi Bulldog,

Thanks, but unfortunately, no change. Still only the 'OK' button on the textbox, not the file contents....

Edit: the file write works, the three entries end up in the correct filename.

Jan Didden

Strange, I just tested it myself (the code I posted) and it worked ok.

Check that your filename is actually created and that it has the correct contents. In the file I see the text as "Bias2535".

Yes the file contents is OK.
Strange. Maybe I should try to write to a listbox for instance?

Jan Didden

An admin thing: how can I copy code from a post into my project? Highlight|Ctrl-C|Ctrl-V doesn't seem to work.

Jan Didden

Try changing this;

Code:

---

            Dim objDataReader As New System.IO.StreamReader(DataFileName)
            MessageBox.Show(objDataReader.ReadToEnd)
            objDataReader.Close()

---

to this;

Code:

---

            Dim objDataReader As New System.IO.StreamReader(DataFileName)
            Dim Result As String = objDataReader.ReadToEnd
            objDataReader.Close()
            MessageBox.Show(Result)

---

Yes that does it! But I have to close the DataWriter stream before doing the DataRead, otherwise I get a runtime exception.

Thanks a bunch, now it's onward to reading/writing CSV-files for Exell....

Have a nice day,

Jan Didden

Please mark the thread resolved if you require no further assistance.

Glad to see your problem was solved. Welcome to the forums!