using lock

[PiotrKolodziej]

Hi
I'am writing a multithread application. This application has let say label1.
This label of course has it's own thread.
Then the question is:
Can i read label1.Text without invoking it just by using such a syntax in
other threads?:
lock(label1)
{
.....
}

Does it prevent from cross-read/write operations?
And one more short question is if i have to use this.invoke when i want to
write to this label1 ( if in previous example it wasn't necessary )?

Thanks or any suggestions
PK

[Brian Gideon]

Re: using lock

PK,

You must use Invoke or BeginInvoke to initiate any access on a Form or
Control from a thread other than the main UI thread. The only
exceptions to that rule are those members that are safe for
multithreaded operations and there aren't many. Not only is the Text
property unsafe for multithreaded operations, but it has
thread-affinity requirements as well which pretty much eliminates the
possibility of using any of the synchronization primitives to guard its
access.

Brian

PiotrKolodziej wrote:

Hi
I'am writing a multithread application. This application has let say label1.
This label of course has it's own thread.
Then the question is:
Can i read label1.Text without invoking it just by using such a syntax in
other threads?:
lock(label1)
{
....
}
>
Does it prevent from cross-read/write operations?
And one more short question is if i have to use this.invoke when i want to
write to this label1 ( if in previous example it wasn't necessary )?
>
Thanks or any suggestions
PK

[PiotrKolodziej]

Re: using lock

You must use Invoke or BeginInvoke to initiate any access on a Form or
Control from a thread other than the main UI thread. The only
exceptions to that rule are those members that are safe for
multithreaded operations and there aren't many. Not only is the Text
property unsafe for multithreaded operations, but it has
thread-affinity requirements as well which pretty much eliminates the
possibility of using any of the synchronization primitives to guard its
access.
>
Brian
>

What if the other thread is the MainThread event? Do i really have to invoke
the reads on label1?

[Brian Gideon]

Re: using lock


PiotrKolodziej wrote:

You must use Invoke or BeginInvoke to initiate any access on a Form or
Control from a thread other than the main UI thread. The only
exceptions to that rule are those members that are safe for
multithreaded operations and there aren't many. Not only is the Text
property unsafe for multithreaded operations, but it has
thread-affinity requirements as well which pretty much eliminates the
possibility of using any of the synchronization primitives to guard its
access.

Brian

>
What if the other thread is the MainThread event? Do i really have to invoke
the reads on label1?

I'm not sure what you mean by the MainThread event. But, yes you have
to invoke reads when InvokeRequired is true. InvokeRequired will be
false when execute on the main UI thread. Otherwise it will be true.

Brian