File.OpenWrite vs StreamWriter

[Harry Strybos]

I am confused about which is the better (or safer ) way to write files in
VB.Net.

Using sw As StreamWriter = New StreamWriter(fN ame)
For Each row As DataRow In ds.Tables(0).Ro ws

For i As Integer = 0 To (ds.Tables(0).C olumns.Count - 1)

col = row(i).ToString .Replace(","c, " "c) 'make sure no extra
commas

If (i < (ds.Tables(0).C olumns.Count - 1)) Then

sw.Write(col & ",")

Else

sw.Write(col)

End If

Next

sw.WriteLine()

Next

sw.Close()

End Using

seems very simple, but I am told this method leaves a file open if an error
occurs. Is the File.OpenWrite a safer method?

Thank you

[Tom Shelton]

On Apr 30, 8:46 pm, "Harry Strybos" <harry_NOS...@f fapaysmart.com. au>
wrote:

I am confused about which is the better (or safer ) way to write files in
VB.Net.

Using sw As StreamWriter = New StreamWriter(fN ame)
For Each row As DataRow In ds.Tables(0).Ro ws

For i As Integer = 0 To (ds.Tables(0).C olumns.Count - 1)

col = row(i).ToString .Replace(","c, " "c) 'make sure no extra
commas

If (i < (ds.Tables(0).C olumns.Count - 1)) Then

sw.Write(col & ",")

Else

sw.Write(col)

End If

Next

sw.WriteLine()

Next

sw.Close()

End Using

seems very simple, but I am told this method leaves a file open if an error

occurs. Is the File.OpenWrite a safer method?

You have been miss informed - when the resource is declared with a
using block, it's dispose method is automatically called as soon as
you exit the block - even if that is via an error condition. In fact,
your sw.Close() is redundant - since the stream will be closed
automatically on the End Using. You can think of Using as being
essentially the same as:

Dim s As New StreamWriter ()
Try
' a bunch of stuff
Finally
s.Close()
End Try

--
Tom Shelton

[Cor Ligthert [MVP]]

Tom,

Nice showing expliciet the nicer code

Dim s As New StreamWriter ()

Cor

[Derek]

Just curious but does the "Using" re-throw the exception afterwards? It
wouldn't be very nice to have my using statements hiding exceptions from the
rest of my code.

i.e.

Try

Catch eX as Exception

Throw

Finally

' Dispose

End Try

[Herfried K. Wagner [MVP]]

"Derek" <de***@nospam.c omschrieb:

Just curious but does the "Using" re-throw the exception afterwards?

Yes.

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://dotnet.mvps.org/dotnet/faqs/>

[Harry Strybos]

"Tom Shelton" <to*********@co mcast.netwrote in message
news:11******** *************@y 5g2000hsa.googl egroups.com...

On Apr 30, 8:46 pm, "Harry Strybos" <harry_NOS...@f fapaysmart.com. au>
wrote:

>I am confused about which is the better (or safer ) way to write files in
VB.Net.

Using sw As StreamWriter = New StreamWriter(fN ame)
For Each row As DataRow In ds.Tables(0).Ro ws

For i As Integer = 0 To (ds.Tables(0).C olumns.Count - 1)

col = row(i).ToString .Replace(","c, " "c) 'make sure no extra
commas

If (i < (ds.Tables(0).C olumns.Count - 1)) Then

sw.Write(col & ",")

Else

sw.Write(col)

End If

Next

sw.WriteLine()

Next

sw.Close()

End Using

seems very simple, but I am told this method leaves a file open if an
error

>occurs. Is the File.OpenWrite a safer method?

You have been miss informed - when the resource is declared with a
using block, it's dispose method is automatically called as soon as
you exit the block - even if that is via an error condition. In fact,
your sw.Close() is redundant - since the stream will be closed
automatically on the End Using. You can think of Using as being
essentially the same as:

Dim s As New StreamWriter ()
Try
' a bunch of stuff
Finally
s.Close()
End Try

--
Tom Shelton

Thanks, guys