how to use Using

[cj]

I'm looking at using Using to try an plug a suspected memory leak. I've
already started using dispose for everything that implements it but no
luck. I have several questions about Using

Can I nest using?

I take it using only applies to resources that it was given as
parameters and will not help with those dimmed inside a using block. Right?

I guess I'm still supposed to close and dispose sql connections and
close files etc before end using?

[AlexS]

You can nest using
You can use Using on connections, files and streams - on anything
implementing IDispose.

HTH
Alex

"cj" <[e-mail] amwrote in message
news:ej******** ******@TK2MSFTN GP02.phx.gbl...

I'm looking at using Using to try an plug a suspected memory leak. I've
already started using dispose for everything that implements it but no
luck. I have several questions about Using

Can I nest using?

I take it using only applies to resources that it was given as parameters
and will not help with those dimmed inside a using block. Right?

I guess I'm still supposed to close and dispose sql connections and close
files etc before end using?

[cj]

So in this code below I should be good with the sql adapter but what
about the streamwriter? Since I dimmed it inside the using block is it
guaranteed to be cleaned up too?

Using Sql2000DesktopD ataAdapter As New
System.Data.Sql Client.SqlDataA dapter("select * from " & sourceTable,
TextBox2.Text)

Try
Sql2000DesktopD ataAdapter.Fill (myds, 0, 10, sourceTable)
Catch ex As Exception
MessageBox.Show ("Error: " & ex.Message)
Exit Sub
End Try
DataGridView1.D ataSource = myds.Tables(sou rceTable)

Dim sw As New System.IO.Strea mWriter("C:\tes t.txt", True)
sw.WriteLine("T ESTING")
sw.Close()
End Using

Or do I have to do this?

Using Sql2000DesktopD ataAdapter As New
System.Data.Sql Client.SqlDataA dapter("select * from " & sourceTable,
TextBox2.Text), sw As New System.IO.Strea mWriter("C:\tes t.txt", True)

Try
Sql2000DesktopD ataAdapter.Fill (myds, 0, 10, sourceTable)
Catch ex As Exception
MessageBox.Show ("Error: " & ex.Message)
Exit Sub
End Try
DataGridView1.D ataSource = myds.Tables(sou rceTable)

sw.WriteLine("T ESTING")
sw.Close()
End Using
cj wrote:

I'm looking at using Using to try an plug a suspected memory leak. I've
already started using dispose for everything that implements it but no
luck. I have several questions about Using

Can I nest using?

I take it using only applies to resources that it was given as
parameters and will not help with those dimmed inside a using block.
Right?

I guess I'm still supposed to close and dispose sql connections and
close files etc before end using?

[Cor Ligthert [MVP]]

cj,

How do you know that you have a memory leak. And please don't tell me that
you have seen that in the taskmanager, one look at Google gives you
thousends of responses that that says nothing.

Cor

"cj" <[e-mail] amschreef in bericht
news:%2******** ********@TK2MSF TNGP06.phx.gbl. ..

So in this code below I should be good with the sql adapter but what about
the streamwriter? Since I dimmed it inside the using block is it
guaranteed to be cleaned up too?

Using Sql2000DesktopD ataAdapter As New
System.Data.Sql Client.SqlDataA dapter("select * from " & sourceTable,
TextBox2.Text)

Try
Sql2000DesktopD ataAdapter.Fill (myds, 0, 10, sourceTable)
Catch ex As Exception
MessageBox.Show ("Error: " & ex.Message)
Exit Sub
End Try
DataGridView1.D ataSource = myds.Tables(sou rceTable)

Dim sw As New System.IO.Strea mWriter("C:\tes t.txt", True)
sw.WriteLine("T ESTING")
sw.Close()
End Using

Or do I have to do this?

Using Sql2000DesktopD ataAdapter As New
System.Data.Sql Client.SqlDataA dapter("select * from " & sourceTable,
TextBox2.Text), sw As New System.IO.Strea mWriter("C:\tes t.txt", True)

Try
Sql2000DesktopD ataAdapter.Fill (myds, 0, 10, sourceTable)
Catch ex As Exception
MessageBox.Show ("Error: " & ex.Message)
Exit Sub
End Try
DataGridView1.D ataSource = myds.Tables(sou rceTable)

sw.WriteLine("T ESTING")
sw.Close()
End Using
cj wrote:

>I'm looking at using Using to try an plug a suspected memory leak. I've
already started using dispose for everything that implements it but no
luck. I have several questions about Using

Can I nest using?

I take it using only applies to resources that it was given as parameters
and will not help with those dimmed inside a using block. Right?

I guess I'm still supposed to close and dispose sql connections and close
files etc before end using?

[Rory Becker]

cj,

>
How do you know that you have a memory leak. And please don't tell me
that you have seen that in the taskmanager, one look at Google gives
you thousends of responses that that says nothing.

Cor

On a very slightly related point....

Cor... I'm curious... I have observed processes in Taskmanager (in this case
not .Net but Ruby) which appeared to eternally use greater and greater quantities
of memory (presumably)as time goes on.

I can understand that due to garbage collection issues (in either Ruby or
..Net) that taskmanager's absolute concept of memory usage for a given process
can be way off.

However, when memory keeps going up and up and up, it becomes fairly clear
that something is up.

Now granted, I have no Idea if this is what the OP is experiencing, but doesn't
this mean that TaskManager isn't entirely useless in detecting at least the
existence of a problem?

--
Rory

[AlexS]

Use nested Using:

Using sw As New System.IO.Strea mWriter("C:\tes t.txt", True)

sw.WriteLine("T ESTING")
sw.Close()

end using

I don't remember if sw is IDisposable, but compiler will tell you

HTH

"cj" <[e-mail] amwrote in message
news:%2******** ********@TK2MSF TNGP06.phx.gbl. ..

So in this code below I should be good with the sql adapter but what about
the streamwriter? Since I dimmed it inside the using block is it
guaranteed to be cleaned up too?

Using Sql2000DesktopD ataAdapter As New
System.Data.Sql Client.SqlDataA dapter("select * from " & sourceTable,
TextBox2.Text)

Try
Sql2000DesktopD ataAdapter.Fill (myds, 0, 10, sourceTable)
Catch ex As Exception
MessageBox.Show ("Error: " & ex.Message)
Exit Sub
End Try
DataGridView1.D ataSource = myds.Tables(sou rceTable)

Dim sw As New System.IO.Strea mWriter("C:\tes t.txt", True)
sw.WriteLine("T ESTING")
sw.Close()
End Using

Or do I have to do this?

Using Sql2000DesktopD ataAdapter As New
System.Data.Sql Client.SqlDataA dapter("select * from " & sourceTable,
TextBox2.Text), sw As New System.IO.Strea mWriter("C:\tes t.txt", True)

Try
Sql2000DesktopD ataAdapter.Fill (myds, 0, 10, sourceTable)
Catch ex As Exception
MessageBox.Show ("Error: " & ex.Message)
Exit Sub
End Try
DataGridView1.D ataSource = myds.Tables(sou rceTable)

sw.WriteLine("T ESTING")
sw.Close()
End Using
cj wrote:

>I'm looking at using Using to try an plug a suspected memory leak. I've
already started using dispose for everything that implements it but no
luck. I have several questions about Using

Can I nest using?

I take it using only applies to resources that it was given as parameters
and will not help with those dimmed inside a using block. Right?

I guess I'm still supposed to close and dispose sql connections and close
files etc before end using?

[Herfried K. Wagner [MVP]]

"cj" <[e-mail] amschrieb:

Can I nest using?

Yes. You can even write 'Using a, b, c, d ... End Using' instead of more
than one nested 'Using' block.

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

[Tom Shelton]

On Jun 22, 2:14 pm, cj <[e-mail] spamwrote:

I'm looking at using Using to try an plug a suspected memory leak. I've
already started using dispose for everything that implements it but no
luck. I have several questions about Using

Can I nest using?

Sure. Not a problem. You can also put all your IDisposable objects
in one using.

I take it using only applies to resources that it was given as
parameters and will not help with those dimmed inside a using block. Right?

Yep.

I guess I'm still supposed to close and dispose sql connections and
close files etc before end using?

Nope. Close is simply a call to there internal clean up methods. In
other words, there is no difference between calling close and
dispose. Close is just more natural symantically...

--
Tom Shelton

[Cor Ligthert [MVP]]

Rory,

I have the idea that Willy has written about this subject the most in dept.

http://groups.google.com/group/micro...kmanager+willy

Have a look at it,

Cor

"Rory Becker" <Ro********@new sgroup.nospamsc hreef in bericht
news:b0******** *************** ***@msnews.micr osoft.com...

>cj,

How do you know that you have a memory leak. And please don't tell me
that you have seen that in the taskmanager, one look at Google gives
you thousends of responses that that says nothing.

Cor

On a very slightly related point....

Cor... I'm curious... I have observed processes in Taskmanager (in this
case not .Net but Ruby) which appeared to eternally use greater and
greater quantities of memory (presumably)as time goes on.
I can understand that due to garbage collection issues (in either Ruby or
.Net) that taskmanager's absolute concept of memory usage for a given
process can be way off.

However, when memory keeps going up and up and up, it becomes fairly clear
that something is up.

Now granted, I have no Idea if this is what the OP is experiencing, but
doesn't this mean that TaskManager isn't entirely useless in detecting at
least the existence of a problem?

--
Rory

[cj]

Thanks! One little followup. When you say I don't have to call
closing, is that because end using calls the cleanup method?

Tom Shelton wrote:

On Jun 22, 2:14 pm, cj <[e-mail] spamwrote:

>I'm looking at using Using to try an plug a suspected memory leak. I've
already started using dispose for everything that implements it but no
luck. I have several questions about Using

Can I nest using?

Sure. Not a problem. You can also put all your IDisposable objects
in one using.

>I take it using only applies to resources that it was given as
parameters and will not help with those dimmed inside a using block. Right?

Yep.

>I guess I'm still supposed to close and dispose sql connections and
close files etc before end using?

Nope. Close is simply a call to there internal clean up methods. In
other words, there is no difference between calling close and
dispose. Close is just more natural symantically...

--
Tom Shelton