Multithreading - Accessing Object

[Tim]

An object 'X' is created inside a thread by object 'A'. The functionality of
object 'X' is used only inside that thread. Inside the thread procedure, the
object 'X's methods are called. That object has a Dispose method that needs
to be called.

The Dispose method of object 'X' has to be called finally when the object
'A' is disposed. Is it okay to call the Dispose method of the object 'X'
outside the thread procedure i.e. in the object A's Dispose method which is
in another thread. The thread procedure has exited before the object 'A's
Dispose method is called.

[Nicholas Paldino [.NET/C# MVP]]

Re: Multithreading - Accessing Object

Tim,

Dispose methods should be designed to be thread-safe as well, so whether
or not it is safe to call depends on whether or not you made it thread safe.

However, you state that object X is only used inside a thread. If that
is the case, then why not just use a using statement so that when you exit
the thread, you dispose of X, since you won't need it anymore?

Hope this helps.


--
- Nicholas Paldino [.NET/C# MVP]
- mvp@spam.guard. caspershouse.co m

"Tim" <Tim@discussion s.microsoft.com > wrote in message
news:52A34643-7713-426E-8599-F9A610836E01@mi crosoft.com...[color=blue]
>
> An object 'X' is created inside a thread by object 'A'. The functionality
> of
> object 'X' is used only inside that thread. Inside the thread procedure,
> the
> object 'X's methods are called. That object has a Dispose method that
> needs
> to be called.
>
> The Dispose method of object 'X' has to be called finally when the object
> 'A' is disposed. Is it okay to call the Dispose method of the object 'X'
> outside the thread procedure i.e. in the object A's Dispose method which
> is
> in another thread. The thread procedure has exited before the object 'A's
> Dispose method is called.
>
>
>
>[/color]

[Tim]

Re: Multithreading - Accessing Object

Hi Nicholas,

Thanks for the immediate response. If the Dispose method of the object 'X'
is called in the thread, fxCop gives a 'Microsoft.Usag e' warning that the
Dispose method of object 'X' has to be called in the Dispose method of object
'A'. Any implications of ignoring this warning? What needs to be done to make
the Dispose method 'Thread-safe'?

"Nicholas Paldino [.NET/C# MVP]" wrote:
[color=blue]
> Tim,
>
> Dispose methods should be designed to be thread-safe as well, so whether
> or not it is safe to call depends on whether or not you made it thread safe.
>
> However, you state that object X is only used inside a thread. If that
> is the case, then why not just use a using statement so that when you exit
> the thread, you dispose of X, since you won't need it anymore?
>
> Hope this helps.
>
>
> --
> - Nicholas Paldino [.NET/C# MVP]
> - mvp@spam.guard. caspershouse.co m
>
> "Tim" <Tim@discussion s.microsoft.com > wrote in message
> news:52A34643-7713-426E-8599-F9A610836E01@mi crosoft.com...[color=green]
> >
> > An object 'X' is created inside a thread by object 'A'. The functionality
> > of
> > object 'X' is used only inside that thread. Inside the thread procedure,
> > the
> > object 'X's methods are called. That object has a Dispose method that
> > needs
> > to be called.
> >
> > The Dispose method of object 'X' has to be called finally when the object
> > 'A' is disposed. Is it okay to call the Dispose method of the object 'X'
> > outside the thread procedure i.e. in the object A's Dispose method which
> > is
> > in another thread. The thread procedure has exited before the object 'A's
> > Dispose method is called.
> >
> >
> >
> >[/color]
>
>
>[/color]

[Truong Hong Thi]

Re: Multithreading - Accessing Object

Hi Tim,

Is it necessary to declare X as class level variable? If you only use
it in the thread proc, consider declare it as local variable, and use
"using" or "finally" to dispose it.

If it is necessary to declare it at class level (e.g. to maintain some
state), then, it is likely that fxCop is right, you should dispose X in
A's dispose. Because, as you said in your original post, "the thread
procedure has exited before the object 'A's
Dispose method is called.", so there is no need to worry about
multi-threaded issues, which only matter if more than one thread access
a resource *at the same time*.

Regards,
Thi

[Tim]

Re: Multithreading - Accessing Object

Thanks Truong. I didn't realize that the fxcop error was because the object
was declared at the class level. I have now declared the variable as a local
variable. Also, Thanks Nicholas for the help regarding 'Using' in C#.

"Truong Hong Thi" wrote:
[color=blue]
> Hi Tim,
>
> Is it necessary to declare X as class level variable? If you only use
> it in the thread proc, consider declare it as local variable, and use
> "using" or "finally" to dispose it.
>
> If it is necessary to declare it at class level (e.g. to maintain some
> state), then, it is likely that fxCop is right, you should dispose X in
> A's dispose. Because, as you said in your original post, "the thread
> procedure has exited before the object 'A's
> Dispose method is called.", so there is no need to worry about
> multi-threaded issues, which only matter if more than one thread access
> a resource *at the same time*.
>
> Regards,
> Thi
>
>[/color]