CODING PRACTICE: Returning from function inside a TRY/CATCH block?

[=?Utf-8?B?U2F2dm91bGlkaXMgSW9yZGFuaXM=?=]

Is it right when placing the RETURN statement inside the TRY or inside the
CATCH statement, when there is a FINALLY clause? Especially when there is a
transaction going on, in the try/catch block?

I give you the following example to meka it more clear:
(I use Enterprise Library, but the same also applies without it)

public function f_SomeFunction( parm1,....) as integer
dim tr as DbTransaction

Using conn As DbConnection = db.CreateConnec tion()
conn.Open()

tr = conn.BeginTrans action()

try
...db action 1
...db action 2
...db action 3
tr.Commit()
return 1

catch ex as Exception
tr.Rollback()
Dim rethrow As Boolean = ExceptionPolicy .HandleExceptio n(ex,
"POLICY_NAME_HE RE")
If rethrow Then
Throw
End If

return -1

finally
conn.Close()
end try
end using
end function

Or instead, I should just set a flag variable rather than commiting/rolling
back (eg. b_ok to TRUE in the TRY clause or FALSE in the CATCH block) and
then check its value outside the TRY/CATCH block or the Using block and see
if I should Return 1 or -1?

I don't know if it's just a matter of programming preference or I could
sometime get unexpected behavior. Which is the common practice? Any help is
appreciated

TIA
Iordanis

[Peter Lykkegaard]

Re: CODING PRACTICE: Returning from function inside a TRY/CATCH block?

"Savvoulidi s Iordanis" wrote

Is it right when placing the RETURN statement inside the TRY or inside the
CATCH statement, when there is a FINALLY clause?
>

When ever you have a return statement you are exiting your method
immediately and the connection is not closed

- Peter

[George]

Re: CODING PRACTICE: Returning from function inside a TRY/CATCH block?

That is incorrrect..

If you closing your connection inside of Finally block then even if you
exiting with Return Finally block will run and connection will close...

George.


"Peter Lykkegaard" <pl@teklogix.dk wrote in message
news:u2unNSb6IH A.1428@TK2MSFTN GP06.phx.gbl...

"Savvoulidi s Iordanis" wrote
>

>Is it right when placing the RETURN statement inside the TRY or inside
>the
>CATCH statement, when there is a FINALLY clause?
>>

When ever you have a return statement you are exiting your method
immediately and the connection is not closed
>
- Peter

[George]

Re: CODING PRACTICE: Returning from function inside a TRY/CATCH block?

Your code is perfectly fine except a little confusing.
If you using "Using" statement then i do not see need to use try/finally
block. Use one or another. You do not need both. But in your case you want
to actually catch exception so kill the Using statement.
Just move tr = conn.BeginTrans action() into try statement.
So i would rewrite it as follow (I moved tr = conn.BeginTrans action()
and also checking on tr not beign Nothing befor doing tr.Rollback since
BeginTransactio n can throw an error and tr will be Nothing

public function f_SomeFunction( parm1,....) as integer
dim tr as DbTransaction
Dim conn As DbConnection = db.CreateConnec tion()
conn.Open()
try
tr = conn.BeginTrans action()
...db action 1
...db action 2
...db action 3
tr.Commit()
return 1
catch ex as Exception
if( Not tr Is Nothing )
tr.Rollback()
Dim rethrow As Boolean = ExceptionPolicy .HandleExceptio n(ex,
"POLICY_NAME_HE RE")
If rethrow Then
Throw
End If
return -1
finally
conn.Close()
end try
end function



George.


"Savvoulidi s Iordanis" <SavvoulidisIor danis@discussio ns.microsoft.co mwrote
in message news:2838406D-6955-466D-A5AF-B65B5C785EB2@mi crosoft.com...

Is it right when placing the RETURN statement inside the TRY or inside the
CATCH statement, when there is a FINALLY clause? Especially when there is
a
transaction going on, in the try/catch block?
>
I give you the following example to meka it more clear:
(I use Enterprise Library, but the same also applies without it)
>
public function f_SomeFunction( parm1,....) as integer
dim tr as DbTransaction
>
Using conn As DbConnection = db.CreateConnec tion()
conn.Open()
>
tr = conn.BeginTrans action()
>
try
...db action 1
...db action 2
...db action 3
tr.Commit()
return 1
>
catch ex as Exception
tr.Rollback()
Dim rethrow As Boolean = ExceptionPolicy .HandleExceptio n(ex,
"POLICY_NAME_HE RE")
If rethrow Then
Throw
End If
>
return -1
>
finally
conn.Close()
end try
end using
end function
>
Or instead, I should just set a flag variable rather than
commiting/rolling
back (eg. b_ok to TRUE in the TRY clause or FALSE in the CATCH block) and
then check its value outside the TRY/CATCH block or the Using block and
see
if I should Return 1 or -1?
>
I don't know if it's just a matter of programming preference or I could
sometime get unexpected behavior. Which is the common practice? Any help
is
appreciated
>
TIA
Iordanis

[Peter Lykkegaard]

Re: CODING PRACTICE: Returning from function inside a TRY/CATCH block?

"George" skrev

That is incorrrect..
>

Ok thanks for the correction :)

- Peter

[Peter Lykkegaard]

Re: CODING PRACTICE: Returning from function inside a TRY/CATCH block?

"George" skrev

That is incorrrect..
>

Ok thanks for the correction :)

- Peter

[Mark Stevens]

Re: CODING PRACTICE: Returning from function inside a TRY/CATCH block?

On Sat, 19 Jul 2008 12:27:16 -0400, "George" <noemail@comcas t.net>
wrote:

>If you using "Using" statement then i do not see need to use try/finally
>block. Use one or another. You do not need both. But in your case you want

Correct me if I am wrong, but doesn't "using" tell the run-time system
to release any resources as soon as possible? This is a little
different from using the finally block to close the connection.

Also, in answer to the original poster, it is often considered good
style to only have one exit point from a method.

Regards
Mark
--
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Mark Stevens (mark at thepcsite fullstop co fullstop uk)

This message is provided "as is".

[Mark Rae [MVP]]

Re: CODING PRACTICE: Returning from function inside a TRY/CATCH block?

"Mark Stevens" <nevyn@nospam.n ospamwrote in message
news:96v5841g56 1rl9en13ms5tn3l b8ets68hs@4ax.c om...

>If you using "Using" statement then i do not see need to use try/finally
>block. Use one or another. You do not need both. But in your case you
>want

>
Correct me if I am wrong, but doesn't "using" tell the run-time system
to release any resources as soon as possible? This is a little
different from using the finally block to close the connection.

It largely depends what the Try...Finally is used for. However, a Using
block and a Try...Finally construction are most certainly *not* mutually
exclusive. See here straight from the horse's mouth, as it were:

http://msdn.microsoft.com/en-us/library/htd05whh(VS.80).aspx

Also, in answer to the original poster, it is often considered good
style to only have one exit point from a method.

Yes, but only by people for whom such coding aesthetics are more important
than what the code actually does...


--
Mark Rae
ASP.NET MVP

http://www.markrae.net

[=?ISO-8859-1?Q?G=F6ran_Andersson?=]

Re: CODING PRACTICE: Returning from function inside a TRY/CATCH block?

Mark Stevens wrote:

On Sat, 19 Jul 2008 12:27:16 -0400, "George" <noemail@comcas t.net>
wrote:
>

>If you using "Using" statement then i do not see need to use try/finally
>block. Use one or another. You do not need both. But in your case you want

>
Correct me if I am wrong, but doesn't "using" tell the run-time system
to release any resources as soon as possible?

No, it disposes the object at the end of the using block, not sooner.

This is a little
different from using the finally block to close the connection.

No, a using block is just syntactic sugar for a try...finally, so there
is actually no difference at all.

Also, in answer to the original poster, it is often considered good
style to only have one exit point from a method.
>
Regards
Mark

--
Göran Andersson
_____

http://www.guffa.com