More Multithread and UI Forms Update

[John Bowman]

Hi,

I've read "Cybertof"'s thread (04/19/04) & the article he provided in a link
about accessing UI elements from a thread that did not create them. What the
authors are saying makes plenty of sense. However, using the control's
Invoke method handles calling it's methods, but what about accessing the
control's properties from another thread? What's the proper way to do that?

--
John C. Bowman
Software Engineer
Thermo Electron Scientific Instruments Div.
<Remove this before reply> jo*********@thermo.com

[Jon Skeet [C# MVP]]

<"John Bowman" <<Remove this before reply> jo*********@thermo.com>>
wrote:

I've read "Cybertof"'s thread (04/19/04) & the article he provided in a link
about accessing UI elements from a thread that did not create them. What the
authors are saying makes plenty of sense. However, using the control's
Invoke method handles calling it's methods, but what about accessing the
control's properties from another thread? What's the proper way to do that?

Again, through a delegate and Invoke. You shouldn't access the property
directly from a non-UI thread.

--
Jon Skeet - <sk***@pobox.com>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too

[John Bowman]

Jon,

Thanks for the quick reply. I kind of suspected that would be the answer
<g>. However, I don't understand (code wise) how to use Invoke to access a
property. I understand how to use it for accessing a method. Do you just
treat the property of interest as if it's a method that has no arguments?
Any example code?

TIA,

John
"Jon Skeet [C# MVP]" <sk***@pobox.com> wrote in message
news:MP************************@msnews.microsoft.c om...

<"John Bowman" <<Remove this before reply> jo*********@thermo.com>>
wrote:

I've read "Cybertof"'s thread (04/19/04) & the article he provided in a link about accessing UI elements from a thread that did not create them. What the authors are saying makes plenty of sense. However, using the control's
Invoke method handles calling it's methods, but what about accessing the
control's properties from another thread? What's the proper way to do

that?
Again, through a delegate and Invoke. You shouldn't access the property
directly from a non-UI thread.

--
Jon Skeet - <sk***@pobox.com>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too

[Jon Skeet [C# MVP]]

<"John Bowman" <<Remove this before reply> jo*********@thermo.com>>
wrote:

Thanks for the quick reply. I kind of suspected that would be the answer
<g>. However, I don't understand (code wise) how to use Invoke to access a
property. I understand how to use it for accessing a method. Do you just
treat the property of interest as if it's a method that has no arguments?
No - you would have to create a delegate which accessed the property,
and invoke that delegate.
Any example code?

Well, just:

delegate string StringReturningDelegate();

string GetLabelText()
{
return label.Text;
}

....

myControl.Invoke
(new StringReturningDelegate(myControl.GetLabelText());

should work.

--
Jon Skeet - <sk***@pobox.com>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too

[Stoitcho Goutsev \(100\) [C# MVP]]

Hi John,

You can use a method to access a property. This would be a special method
that you call thru Invoke and this method sets or gets the property. The
other way is to create a delegate to invoke the 'get' or 'set' accessor of
the property directly. Hoewever IMHO the first is more easy to use. For
invoking the accessor directly you can follow this link
http://groups.google.ca/groups?hl=en...sor%2Bstoitcho
Look for my post, which is last in the thread.
--
HTH
B\rgds
Stoitcho Goutsev (100) [C# MVP]

"John Bowman jo*********@thermo.com>" <<Remove this before reply> wrote in
message news:u2**************@TK2MSFTNGP09.phx.gbl...

Jon,

Thanks for the quick reply. I kind of suspected that would be the answer
<g>. However, I don't understand (code wise) how to use Invoke to access a
property. I understand how to use it for accessing a method. Do you just
treat the property of interest as if it's a method that has no arguments?
Any example code?

TIA,

John
"Jon Skeet [C# MVP]" <sk***@pobox.com> wrote in message
news:MP************************@msnews.microsoft.c om...

<"John Bowman" <<Remove this before reply> jo*********@thermo.com>>
wrote:

I've read "Cybertof"'s thread (04/19/04) & the article he provided in a

link

about accessing UI elements from a thread that did not create them.

What

the authors are saying makes plenty of sense. However, using the control's
Invoke method handles calling it's methods, but what about accessing

the control's properties from another thread? What's the proper way to do

that?

Again, through a delegate and Invoke. You shouldn't access the property
directly from a non-UI thread.

--
Jon Skeet - <sk***@pobox.com>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too

[John Bowman]

Jon & Stoitcho,

Thanks for the help. I should be able to continue from here.

John
"Stoitcho Goutsev (100) [C# MVP]" <10*@100.com> wrote in message
news:ux**************@tk2msftngp13.phx.gbl...

Hi John,

You can use a method to access a property. This would be a special method
that you call thru Invoke and this method sets or gets the property. The
other way is to create a delegate to invoke the 'get' or 'set' accessor of
the property directly. Hoewever IMHO the first is more easy to use. For
invoking the accessor directly you can follow this link
http://groups.google.ca/groups?hl=en...sor%2Bstoitcho Look for my post, which is last in the thread.
--
HTH
B\rgds
Stoitcho Goutsev (100) [C# MVP]

"John Bowman jo*********@thermo.com>" <<Remove this before reply> wrote in
message news:u2**************@TK2MSFTNGP09.phx.gbl...

Jon,

Thanks for the quick reply. I kind of suspected that would be the answer
<g>. However, I don't understand (code wise) how to use Invoke to access a

property. I understand how to use it for accessing a method. Do you just
treat the property of interest as if it's a method that has no arguments? Any example code?

TIA,

John
"Jon Skeet [C# MVP]" <sk***@pobox.com> wrote in message
news:MP************************@msnews.microsoft.c om...

<"John Bowman" <<Remove this before reply> jo*********@thermo.com>>
wrote:
> I've read "Cybertof"'s thread (04/19/04) & the article he provided in

a

link

> about accessing UI elements from a thread that did not create them. What

the

> authors are saying makes plenty of sense. However, using the

control's > Invoke method handles calling it's methods, but what about accessing

the > control's properties from another thread? What's the proper way to do that?

Again, through a delegate and Invoke. You shouldn't access the

property directly from a non-UI thread.

--
Jon Skeet - <sk***@pobox.com>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too