Programming - Best Practice

[bigHairy]

Hello.

I have been teaching myself .NET over the last few months and have had
some success. I would like to ask a question though...

A number of examples I have followed have the following in their
finally statement

Try
......
Catch
......
Finally

If (Not IsNothing(dbCon n)) Then
dbConn.Close()
End If

End Try

Will my data connection always close using this method or should I
just use dbConn.close?

I have a program that seems to be holding onto its connection - am I
missing something?

[pvdg42]

"bigHairy" <mt*********@gm ail.comwrote in message
news:11******** **************@ m58g2000cwm.goo glegroups.com.. .

Hello.

I have been teaching myself .NET over the last few months and have had
some success. I would like to ask a question though...

A number of examples I have followed have the following in their
finally statement

Try
.....
Catch
.....
Finally

If (Not IsNothing(dbCon n)) Then
dbConn.Close()
End If

End Try

Will my data connection always close using this method or should I
just use dbConn.close?

I have a program that seems to be holding onto its connection - am I
missing something?

If you just use dbConn.Close(), you'll get an exception if the connection in
question is not open.
The code in finally first checks to see if dbConn is an empty reference (no
active connection), and only attempts to close it is there is an active
connection to close.
As code in the finally block is "guaranteed to execute", the code you posted
closes the connection *if* it is open.
The question is, what makes you think the connection remains active after
this code executes?

[bigHairy]

Thanks for your prompt reply, I appreciate the help.

I am currently in discussions with a 3rd party data provider as there
seem to be timeout issues using a linked SQL Server with a Progress
Database. There are suggestions that it may be our program leaving
connections open but I can find no evidence of this - thought I would
check that I am using the best practice for closing these connections
as a first port of call before I go investigating the rest of the
process.

[Zim Babwe]

You could use something like this to close your connection:

If objConn.State = Data.Connection State.Open Then
objConn.Close()
End If


"bigHairy" <mt*********@gm ail.comwrote in message
news:11******** **************@ m58g2000cwm.goo glegroups.com.. .

Hello.

I have been teaching myself .NET over the last few months and have had
some success. I would like to ask a question though...

A number of examples I have followed have the following in their
finally statement

Try
.....
Catch
.....
Finally

If (Not IsNothing(dbCon n)) Then
dbConn.Close()
End If

End Try

Will my data connection always close using this method or should I
just use dbConn.close?

I have a program that seems to be holding onto its connection - am I
missing something?

[Brian Gideon]

On Feb 16, 11:07 am, "Zim Babwe"
<zimba...@doyou reallythinkthis isreal.comwrote :

You could use something like this to close your connection:

If objConn.State = Data.Connection State.Open Then
objConn.Close()
End If

"bigHairy" <mthomas1...@gm ail.comwrote in message

news:11******** **************@ m58g2000cwm.goo glegroups.com.. .

You could call Dispose instead of Close. Dispose will not throw
exceptions. If you're using VB 2005 the Using keyword can clean up
the code quite a bit as well.

[Cor Ligthert [MVP]]

Hi,

AS you ask for Best Practice than you don't definitly not need a test to see
if your connection is open.

You control your program, so you know if it is open or not and can close it
therefore at the right time without any error.

Cor

"Zim Babwe" <zi******@doyou reallythinkthis isreal.comschre ef in bericht
news:Oa******** *****@TK2MSFTNG P04.phx.gbl...

You could use something like this to close your connection:

If objConn.State = Data.Connection State.Open Then
objConn.Close()
End If


"bigHairy" <mt*********@gm ail.comwrote in message
news:11******** **************@ m58g2000cwm.goo glegroups.com.. .

>Hello.

I have been teaching myself .NET over the last few months and have had
some success. I would like to ask a question though...

A number of examples I have followed have the following in their
finally statement

Try
.....
Catch
.....
Finally

If (Not IsNothing(dbCon n)) Then
dbConn.Close ()
End If

End Try

Will my data connection always close using this method or should I
just use dbConn.close?

I have a program that seems to be holding onto its connection - am I
missing something?

[Stephany Young]

The issue here has nothing to do with whether or not the database connection
is open. It is to do with whether or not the database connection object has
been instantiated.

You will probabaly note that the 'examples' have the dbConn variable
declared before the Try. This means that the dbConn variable is 'scoped' so
that it is available to the Finally block.

With both the SqlConnection and OleDbConnection classes, calling Close on an
object of those types that is not open will NOT cause an exception. However,
if you call Close on an object of those types that has NOT been instantiated
(Is Nothing) then an exception WILL be thrown.

In the Try block, if an exception is thrown before dbConn is instantiated
(let alone opened), the logic will 'jump' directly to the Catch block and
then fall through to the Finally block. At this point dbConn would be
Nothing and a call to dbConn.Close would fail. The conditional execution of
dbConn.Close handles this situation.

Because the code Finally block is executed regardless of whether an
exception was thrown or not, having the conditional execution of
dbConn.Close means that you do not need to worrying about closing the
connection in either the Try or Catch blocks.
"bigHairy" <mt*********@gm ail.comwrote in message
news:11******** **************@ m58g2000cwm.goo glegroups.com.. .

Hello.

I have been teaching myself .NET over the last few months and have had
some success. I would like to ask a question though...

A number of examples I have followed have the following in their
finally statement

Try
.....
Catch
.....
Finally

If (Not IsNothing(dbCon n)) Then
dbConn.Close()
End If

End Try

Will my data connection always close using this method or should I
just use dbConn.close?

I have a program that seems to be holding onto its connection - am I
missing something?

[pfc_sadr]

I didn't think that you could even leave a connection open.

it's one of my biggest complaints about ADO.net; I used to use @@SPID
similiar to sessionID in ASP in order to build some simple apps...

but now there is nothing like that in .NET from what I understand

I just don't understand; why do you even need to close a connection if
you can't leave a connection OPEN?
like I'm being serious and honest here.

Thanks

On Feb 16, 12:04 pm, "Stephany Young" <noone@localhos twrote:

The issue here has nothing to do with whether or not the database connection
is open. It is to do with whether or not the database connection object has
been instantiated.

You will probabaly note that the 'examples' have the dbConn variable
declared before the Try. This means that the dbConn variable is 'scoped' so
that it is available to the Finally block.

With both the SqlConnection and OleDbConnection classes, calling Close on an
object of those types that is not open will NOT cause an exception. However,
if you call Close on an object of those types that has NOT been instantiated
(Is Nothing) then an exception WILL be thrown.

In the Try block, if an exception is thrown before dbConn is instantiated
(let alone opened), the logic will 'jump' directly to the Catch block and
then fall through to the Finally block. At this point dbConn would be
Nothing and a call to dbConn.Close would fail. The conditional execution of
dbConn.Close handles this situation.

Because the code Finally block is executed regardless of whether an
exception was thrown or not, having the conditional execution of
dbConn.Close means that you do not need to worrying about closing the
connection in either the Try or Catch blocks.

"bigHairy" <mthomas1...@gm ail.comwrote in message

news:11******** **************@ m58g2000cwm.goo glegroups.com.. .

Hello.

I have been teaching myself .NET over the last few months and have had
some success. I would like to ask a question though...

A number of examples I have followed have the following in their
finally statement

Try
.....
Catch
.....
Finally

If (Not IsNothing(dbCon n)) Then
dbConn.Close()
End If

End Try

Will my data connection always close using this method or should I
just use dbConn.close?

I have a program that seems to be holding onto its connection - am I
missing something?

[Brian Gideon]

On Feb 16, 3:00 pm, pfc_s...@hotmai l.com wrote:

I didn't think that you could even leave a connection open.

it's one of my biggest complaints about ADO.net; I used to use @@SPID
similiar to sessionID in ASP in order to build some simple apps...

but now there is nothing like that in .NET from what I understand

I just don't understand; why do you even need to close a connection if
you can't leave a connection OPEN?

like I'm being serious and honest here.

Thanks

Hi,

What made you think you couldn't leave a connection open?

Brian

[PFC Sadr]

uh a half dozen MS press books???
uh a half dozen MS press books???
uh a half dozen MS press books???
get a spid; get another SPID.

DO THEY MATCH?

because if they do then I'll accept a written apology from Microsoft
and new editions of their books that are CORRECTED.
On Feb 16, 1:48 pm, "Brian Gideon" <briangid...@ya hoo.comwrote:

On Feb 16, 3:00 pm, pfc_s...@hotmai l.com wrote:

I didn't think that you could even leave a connection open.

it's one of my biggest complaints about ADO.net; I used to use @@SPID
similiar to sessionID in ASP in order to build some simple apps...

but now there is nothing like that in .NET from what I understand

I just don't understand; why do you even need to close a connection if
you can't leave a connection OPEN?

like I'm being serious and honest here.

Thanks

Hi,

What made you think you couldn't leave a connection open?

Brian