Accessesing GUI from different thread

[Steve N.]

Whats the best way to access .net GUI classes from a spawned thread? Is
this even advisable, or is it a sign that the design is wrong?

Any input, links, etc., would be helpful. Thanks!

Steve

[Tomas Restrepo \(MVP\)]

Re: Accessesing GUI from different thread

Steve,
[color=blue]
> Whats the best way to access .net GUI classes from a spawned thread? Is
> this even advisable, or is it a sign that the design is wrong?[/color]

It is certainly possible, and certainly necessary at times. It's not
necessarily a wrong thing, though in some cases there might be alternatives.

That said, you do have to take a few things into account, and make sure you
marshal the GUI access back to the main thread (so that you never touch the
gui controls from secondary threads), but, fortunately, the .NET framework
provides a mechanism for this.

Here's a good article on the topic (it's in C#, but the principles are the
same):
http://www.code-magazine.com/article...0403071&page=1


--
Tomas Restrepo
tomasr@mvps.org

http://www.winterdom.com/

[Arnaud Debaene]

Re: Accessesing GUI from different thread

Steve N. wrote:[color=blue]
> Whats the best way to access .net GUI classes from a spawned thread?
> Is this even advisable, or is it a sign that the design is wrong?[/color]

The design is not wrong, but you jmust be careful to make your GUI API
thread-safe : each public function of your GUI objects that may be called on
different threads should begin by something like this (in C# for ease of
syntax, but you've got the idea) :

delegate void DoSomethingDele gate(params...) ///DoSomethingDele gate matches
DoSomething'sig nature
void DoSomething(par ams....)
{
if (InvokeRequired )
{
BeginInvoke (new DoSomethingDele gate(DoSomethin g, new object[]
{params...}));
return;
}

//normal GUI stuff
}

Arnaud
MVP - VC

[Steve N.]

Re: Accessesing GUI from different thread

Tomas Restrepo (MVP) wrote:[color=blue]
> That said, you do have to take a few things into account, and make sure you
> marshal the GUI access back to the main thread (so that you never touch the
> gui controls from secondary threads), but, fortunately, the .NET framework
> provides a mechanism for this.
>
> Here's a good article on the topic (it's in C#, but the principles are the
> same):
> http://www.code-magazine.com/article...0403071&page=1[/color]

Yes, I got it working, thank you.