"IOException was unhandled" that error keeps appearing

Question

Im having this problem and it doesnt seem to go away. Theres a code ive done in vb.net, in which i to to stream files but i keep on getting that error

"IOException was unhandled" The process cannot access the file 'C:\Users\Lenovo\documents\visual studio 2010\Projects\File streaming\File Streaming\bin\Debug\banking.xls' because it is being used by another process.

Heres the code:

Imports System.IO

Imports System.Windows.Forms.Form
Public Class Form1

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

    End Sub

    Private Sub btnDisplay_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplay.Click

        Dim FileStr As New FileStream("banking.xls", FileMode.Create, FileAccess.Write)

        Dim a As New StreamWriter(FileStr)

        'a.WriteLine("File should be displayed in the RTB............")
        'a.Close()

       **ERROR APPEARS HERE**     
        FileStr = New FileStream("banking.xls", FileMode.Open, FileAccess.Read)

        Dim i As New StreamReader(FileStr)

        i.BaseStream.Seek(0, SeekOrigin.Begin)

        If i.Peek() > -1 Then

            rtbDisplay.Text &= i.ReadLine()

        End If
        i.Close()

    End Sub

    Private Sub btnClear_Click(sender As System.Object, e As System.EventArgs) Handles btnClear.Click

        rtbDisplay.Text = ""

    End Sub

    Private Sub btnExit_Click(sender As System.Object, e As System.EventArgs) Handles btnExit.Click

        Me.Close()

    End Sub

    Private Function FileStream() As Object
        Throw New NotImplementedException
    End Function

End Class

sorry theres no c++, or i think. Im still new so i wouldnt know to be exact — Ervin Matlapeng, Nov 15 '17 at 13:46
Put your streams in Using statement to make sure everything is closed properly. Sometime having the same file open causes a problem. Is there an other process that tries to open the file? — the_lotus, Nov 15 '17 at 13:47
the_lotus im trying to understand what exactly it is that you saying, remember im very very new to vb — Ervin Matlapeng, Nov 15 '17 at 13:57
[`Using` statement](https://learn.microsoft.com/en-us/dotnet/visual-basic/language-reference/statements/using-statement) — Visual Vincent, Nov 15 '17 at 14:09
But the file *is* open with `Dim a As New StreamWriter(FileStr)` — djv, Nov 15 '17 at 15:36

score 2 · Answer 1 · answered Nov 15 '17 at 15:45

2

FileStream and StreamWriter are IDisposable objects, and should be disposed when you are done with them. when IDisposable have local scope, it is good practice to create them with a Using block.

Sub Main()
    Using FileStr As New FileStream("banking.xls", FileMode.Create, FileAccess.Write)
        Using a As New StreamWriter(FileStr)
            a.WriteLine("File should be displayed in the RTB............")
        End Using
    End Using

    Using FileStr = New FileStream("banking.xls", FileMode.Open, FileAccess.Read)
        Dim i As New StreamReader(FileStr)
    End Using
End Sub

Still, I don't know why you are writing text to an xls file like this. If you are manipulating Excel files, you should look at Open Xml or Microsoft Office Interop

answered Nov 15 '17 at 15:45

djv

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Mostly I agree about Open Xml or Interop. Sometimes, though, you can do an "excel lite" effect by working with a tab-delimited text file that has an xls extension. Excel will open this and treat it as a native file. You just need to be careful, because once the real Excel saves new info to that file, you're dealing with the full Excel format. – Joel Coehoorn Nov 15 '17 at 15:50
@JoelCoehoorn interesting. I work a lot with tab delim txt and *Open with >> Excel* often. After a quick test, you are right that it works with xls extension, though there's a warning message when opening the file. It doesn't work with the newer xlsx extension however. – djv Nov 15 '17 at 15:56
Id really appreciate your help with what you just mentioned! i have no clue as to what you are saying. im still new in this field – Ervin Matlapeng Nov 16 '17 at 09:14

"IOException was unhandled" that error keeps appearing

1 Answers1