[serious] My first VB.Net App!

[thegreatone]

It just took me 20minutes to write my first VB.Net App (.Net FW 2)
There is no error handling or anything, but, it works!
Any tips in error handling? Or even how to do it...

Simply it strips Extended info and wma files from a winamp playlist.

Imports System.IO
Public Class Form1
 
    Private Sub CMDOpenFile_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CMDOpenFile.Click
        Dim FileName As String
        CDopen.Filter = "M3U Playlist|*.m3u|All Files|*.*"
        CDopen.ShowDialog()
        FileName = CDopen.FileName.ToString
        Dim s As String
        If FileName <> "" Then
            Dim sr As New StreamReader(FileName)
            While sr.Peek <> -1
                s = sr.ReadLine.ToString
                List1.Items.Add(s)
            End While
            sr.Close()
        End If
        Label1.Text = "Line Count: " & List1.Items.Count()
    End Sub
 
    Private Sub CMDparse_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CMDparse.Click
        Dim i As Long
        For i = List1.Items.Count() - 1 To 0 Step -1
            Me.List1.SelectedIndex = i
            If List1.Text.StartsWith("#EXT") Or List1.Text.EndsWith(".wma") Then
                List1.Items.Remove(List1.Text)
            End If
            Label1.Text = "Line Count: " & List1.Items.Count()
        Next
    End Sub
 
    Private Sub CMDsave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CMDsave.Click
        Dim i As Integer
        Dim FileName As String
        Dim sw As StreamWriter
        CDsave.Filter = "M3U Playlist|*.m3u|All Files|*.*"
        CDsave.ShowDialog()
        FileName = CDsave.FileName
        If FileName <> "" Then
            sw = New StreamWriter(FileName)
            For i = 0 To List1.Items.Count - 1
                sw.WriteLine(List1.Items.Item(i))
            Next
            sw.Close()
        End If
    End Sub
End Class

[penagate]

Congratulations, now learn C#

[thegreatone]

Congratulations, now learn C#

Psst, that is what i was learning... I thought it was taking a bit too long, so i whipped up an app to do this is minutes.

P.S. Updated the code

[grilkip]

Error handling in .NET is done with TRY/CATCH blocks.

Try
'code that may produce an error
Catch (e As Exception)
'code that will be executed if there is an error
Finally
'code that will be executed in any case
End Try

The Finally block can be left out if you don't need it.

Could seem less convenient then ON ERROR GOTO from vb6 (which still works btw), but it is much better. I will personally murder you if you use ON ERROR GOTO.

Furthermore, perform a few sanity checks, like does the file exist to begin with, etc.

[penagate]

Use Try/Catch as an absolute last resort - if an exception is the only way to handle a condition.

[thegreatone]

Error handling in .NET is done with TRY/CATCH blocks.

Try
'code that may produce an error
Catch (e As Exception)
'code that will be executed if there is an error
Finally
'code that will be executed in any case
End Try

The Finally block can be left out if you don't need it.

Could seem less convenient then ON ERROR GOTO from vb6 (which still works btw), but it is much better. I will personally murder you if you use ON ERROR GOTO.

Furthermore, perform a few sanity checks, like does the file exist to begin with, etc.

So

Private Sub CMDparse_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CMDparse.Click
        Dim i As Long
        For i = List1.Items.Count() - 1 To 0 Step -1
            Me.List1.SelectedIndex = i
            If List1.Text.StartsWith("#EXT") Or List1.Text.EndsWith(".wma") Then
                List1.Items.Remove(List1.Text)
            End If
            Label1.Text = "Line Count: " & List1.Items.Count()
        Next
    End Sub

Would become:

Private Sub CMDparse_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CMDparse.Click
        Dim i As Long
Try
        For i = List1.Items.Count() - 1 To 0 Step -1
            Me.List1.SelectedIndex = i
            If List1.Text.StartsWith("#EXT") Or List1.Text.EndsWith(".wma") Then
                List1.Items.Remove(List1.Text)
            End If
        Next
Catch (e as Exception)
    MsgBox("There has been an error!")
Finally
    Label1.Text = "Line Count: " & List1.Items.Count()
End Try
    End Sub

?

[penagate]

No... that would be acase for murder, there will never be an exception generated in that bit of code unless you have a logic error. In which case you don't want to handle the exception, you want it to crash so you can debug it.

Use sanity checks like grilkip said, like File.Exists(FileName) before opening the file, etc. Although, I can't remember, but the dialog might not even let you specify a non-existant file in the first place. If that's the case then you wouldn't need to check it.

[thegreatone]

No... that would be acase for murder, there will never be an exception generated in that bit of code unless you have a logic error. In which case you don't want to handle the exception, you want it to crash so you can debug it.

Use sanity checks like grilkip said, like File.Exists(FileName) before opening the file, etc. Although, I can't remember, but the dialog might not even let you specify a non-existant file in the first place. If that's the case then you wouldn't need to check it.

Ah, thankyou. So basically go as safe as i can then

Cheers.

[wossname]

I'm with Penagate on this one. You should always be able to avoid TryCatch if you write code well, however it is sometimes unavoidable when using some libraries that only give you feedback by the kind of exception thaty they throw (some network and database libs behave this way and its a real ball-ache).

[iPrank]

I can't help you here. But,
Congratulations !