cross thread

[Mihai]

Hi to everybody !

I created a class C1 in VB.Net that get some data from a sql server. From a
form F1 I call this class and get this data and show nicely on a
datagridView.
In this class C1 I defined a public shared string variable.
I defined a public event, too.
When for example I read data from sql server i put a value in this shared
string: "get data from server" for example an raise the event.

On another form F2 I created a handler for the event in class C1.When it is
hapening I want to see the message from the shared string in a listbox that
reside on F2.

I execute F2.is ok
when i execute F1 I have this message error:
Cross-thread operation not valid: Control 'lstboxMessages' accessed from a
thread other than the thread it was created on.

When in F2 i set

Windows.Forms.Control.CheckForIllegalCrossThreadCalls = False

everything is running OK. But I don't know if is right to use this.

Can someone give me another solution , please ? But with 2 forms.

This is like a resume, because in reality F1 is reside on a computer and
call C1 from the server , F2 is on a server.And all this message I want to
see on the server in real time.
If for example I don't use events, manualy update - pressing a button in F2
is running ok without error.Somehow .net don't like using events in this
mode.

Thank you,
Mihai

 

[Cor Ligthert[MVP]]

Miha,

Don't use a modern architecture, working with Net is mostly based on the
bahaviour of Internet.

Data on a Server is never at the millisecond actual (if those who do the
input start drinking coffee is is already not actual).

Some pages on Internet are sometimes refressing by a timer, a way you can
use to.

You can use notification, however you will see that your application becomes
dramaticly slow.
http://www.vb-tips.com/default.aspx?ID=97f5073b-4c42-4215-b71c-3503c15fd46e

Cor

 

[Cor Ligthert[MVP]]

Doh,

I did want to write,

Don't use an ancient architecture but go in a more modern way



Cor

 

[Mihai]

A solution that I found is to use Microsoft queue.I will try this anyway.
I think this is "Modern way".
I'm curios Cor , how you can trace activity on each function , subrutine
etc, that reside in a lot of dlls running on the server, or in a web service
to think in a "Modern way". I want something to trace in real time not
writing in a file or database and after that pressing a button to show the
results.
Anyway I will not use this tracing all the time to slow down the server, but
when I used this function I want to see the results on the screen in a
listbox not in a console application.On a console application, my trace
modul works.

Any other ideas will be appreciated !

Regards,
Mihai

 

[Mihai]

I found the answer by myself !
Create first a binding source. Create a datatable where the event insert the
messages.
db.datasource=dt
Bind the datagridview with binding source and voila is working.
is updating in real time.

Regards,
Mihai

 

[Cor Ligthert[MVP]]

Miha,

Probably is the only part you are looking for synclock.

That you use when you add the data on the end of the queue and when you get
the data from the begin.
(or vice versa that is just how you look at a queue)

http://msdn2.microsoft.com/en-us/library/3a86s51t.aspx

Cor

 

[Cor Ligthert[MVP]]

Mihai,

Did you not do it like that, confirm your text I was thinking you were doing
this already, there was nothing about this in your text and this is of
course obvious.

Cor