ThreadStateException creating ActiveX control in thread

I am creating a plugin for MS Outlook. Upon clicking a toolbar button, I
create series of threads (variable number each time). Within each thread, I
start a form using Application.Run(...). This form contains the Web
Browser ActiveX control. Upon creating the form, I get a
ThreadStateException "Could not instantiate ActiveX control ..... because
the current thread is not in a single-threaded apartment."

Right now, I'm using a ThreadPool to actually create the threads (I just
queue up each item). I've searched around and it looks like I need to set
the thread apartment state to STA instead of MTA, but I'm not sure how to
actually accomplish that here with the thread pool.

Any suggestions?

Thanks!
--
Adam Clauss
ca*****@tamu.edu

Adam,

In order to set the ApartmentState of the current thread, I would do
this:

// Set the apartment state to STA.
Thread.CurrentThread.ApartmentState = ApartmentState.STA;
Well, I had already tried adding that line as the first line of the thread function - it had no effect.
Rather, I would spawn your own threads, and set the apartment state of
those.

"Nicholas Paldino [.NET/C# MVP]" <mv*@spam.guard.caspershouse.com> wrote
in message news:eB***************@TK2MSFTNGP11.phx.gbl...

Adam,

In order to set the ApartmentState of the current thread, I would do
this:

// Set the apartment state to STA.
Thread.CurrentThread.ApartmentState = ApartmentState.STA;

Well, I had already tried adding that line as the first line of the thread
function - it had no effect.

Rather, I would spawn your own threads, and set the apartment state of
those.

Hmm, I'll look at doing that, see if that helps any.

Thanks!
--
Adam Clauss
ca*****@tamu.edu

I am creating a plugin for MS Outlook. Upon clicking a toolbar button, I
create series of threads (variable number each time). Within each thread, I
start a form using Application.Run(...). This form contains the Web
Browser ActiveX control. Upon creating the form, I get a
ThreadStateException "Could not instantiate ActiveX control ..... because
the current thread is not in a single-threaded apartment."

Right now, I'm using a ThreadPool to actually create the threads (I just
queue up each item). I've searched around and it looks like I need to set
the thread apartment state to STA instead of MTA, but I'm not sure how to
actually accomplish that here with the thread pool.

Any suggestions?

Thanks!
--
Adam Clauss
ca*****@tamu.edu

Adam,

Are you calling it in your thread callback? The call needs to be in there to take effect.

Also, it is possible that the value had already been set, in which case, subsequent attempts to set the value are ignored.

You should have no problem if you spawn your own threads.
--
- Nicholas Paldino [.NET/C# MVP]
- mv*@spam.guard.caspershouse.com

"Adam Clauss" <ca*****@tamu.edu> wrote in message news:e2***************@TK2MSFTNGP12.phx.gbl...

"Nicholas Paldino [.NET/C# MVP]" <mv*@spam.guard.caspershouse.com> wrote in message
news:eB***************@TK2MSFTNGP11.phx.gbl...

Adam,

In order to set the ApartmentState of the current thread, I would do this:

// Set the apartment state to STA.
Thread.CurrentThread.ApartmentState = ApartmentState.STA;

Well, I had already tried adding that line as the first line of the thread function - it had no effect.

Rather, I would spawn your own threads, and set the apartment state of those.

Hmm, I'll look at doing that, see if that helps any.

Thanks!
--
Adam Clauss
ca*****@tamu.edu