Add Item to ListBox in Run Time - C# Discussion Boards

Re: mouse cursor

Nader Elshehabi27-Aug-06 14:29

Nader Elshehabi

27-Aug-06 14:29

Hello

You can do that using the TextBox.Cursor property.

Regards

How to get URL on the screen?please..

zhoujun27-Aug-06 13:03

zhoujun

27-Aug-06 13:03

When mouse move over webpage on the screen and stop on a word that is URL,how could I catch the URL from my program?
I hope you got my meaning.Thanks

August 12,2006,Rhythm of The Rain.

Re: How to get URL on the screen?please..

Nader Elshehabi27-Aug-06 13:35

Nader Elshehabi

27-Aug-06 13:35

Hello

If you can access the source of the page, this is easy using javascript, or ASP.

On the other hand -which I think is your case-, if you can't do that, then the only thing I could think of is OCR (Optical Character Recognition). Yes, I guess I've gone too far, but some trnslation programs do that. When you point the cursor to a word and press the HotKey, the recognize the characters off the screen and tranlate them -if possible of course-.

This is way, way too advanced topic. You can get an image of the link easily using Graphics class methods, but interpreting the image to text will certainly need a library.

Regards

keyboard and mouse

xkx3227-Aug-06 9:17

xkx32

27-Aug-06 9:17

Hello,

I'm wondering how it's possible to create an application wide event that's fired when any keyboard or mouse key is pressed and mouse move?

Please help. Thanks

Re: keyboard and mouse

Andy Moore27-Aug-06 9:56

Andy Moore

27-Aug-06 9:56

Look at the KeyPress and MouseMove events in the System.Windows.Forms namespace.

Deus caritas est

Re: keyboard and mouse

beatles169227-Aug-06 11:43

beatles1692

27-Aug-06 11:43

Hi There are usually two ways to handle user inputs (keyboard/mouse).
If you like to hanlde those events in a form you can turn its keypreview property to true and override its OnKeyDown,OnKeyUp,OnMouseDown and etc. metohds to do what you want to do (or you can add a handler using event handlers)
But if you like to handle those events in an application rather than a form you can handle messages that are being send to your application by windows.
Regards

Re: keyboard and mouse

Ed.Poore27-Aug-06 11:51

Ed.Poore

27-Aug-06 11:51

If you want system-wide event notification then you'll have to have a Windows hook me thinks. There is an article on System-wide keyboard hooks here on CP, can't remember what it's called but search for "system wide hotkey" and you should find it.

As of how to accomplish this, have you ever tried Google?

Add Item to ListBox in Run Time

J Liang27-Aug-06 6:59

J Liang

27-Aug-06 6:59

Hi,

I am having problem refreshing the list box after I'd added an item to it.

The situation is like this, from form1, I click Add button to open a new form, let say form2 for me to fill in some details to the textbox, when I click on Add, form2 close and supposingly the list box in form1 should refresh and show the changes but it don't.

From form 1:

private void btnAdd_Click(object sender, EventArgs e)
{
form2.ShowDialog();
}

then form2 opens and it do whatever needed and pass the value using this:

form1.clientName = txtName.Text;
form1.AddToList();

then back to form1:

public void AddToList()
{
lstClientList.Items.Add(this.clientName);
}

usually if lstClientList.Items.Add(this.clientName); is done directly on the btnAdd_Click, it will add and show the changes on the list box but it don't work when I use another form to add.

Would appreciate for your help

Jie Liang

Re: Add Item to ListBox in Run Time

Guffa27-Aug-06 7:52

Guffa

27-Aug-06 7:52

As you are using ShowDialog, form1 isn't doing anything until form2 closes.

Add the item after the call to ShowDialog, instead of calling a method from form2.

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Re: Add Item to ListBox in Run Time

J Liang27-Aug-06 15:29

J Liang

27-Aug-06 15:29

Hi Guffa,

Thanks for the advice, it really does work Smile | :)

Jie Liang

Timing question with multithreading

mav.northwind27-Aug-06 6:07

mav.northwind

27-Aug-06 6:07

Hi folks!

I've just observed a behaviour I cannot understand - perhaps someone can shed some light on it...

For demonstration purpose I wrote a little program where two threads are incrementing a value, just to show someone the need for synchronization.

Everything works as expected, but then I wondered if I could measure any performance differences between using lock(this) and lock(someLockingObject) when I'm not using 2 threads running the same loop but using 4 threads with the same loop for every two of them.

When I execute the application run on my Athlon64 X2 and assign it to just one core, it's running faster than when I assign it to both cores!?

How can that be?

Regards,
mav

--
Black holes are the places where god divided by 0...

Re: Timing question with multithreading

Ed.Poore27-Aug-06 11:53

Ed.Poore

27-Aug-06 11:53

Probably scheduling between threads and procesors. It you modified your program to execute either loop depending on a command-line argument / button / whatever and load the two copies onto different processors then you'll probably get a faster output. But I don't know if this is what you want to accomplish.

As of how to accomplish this, have you ever tried Google?

Re: Timing question with multithreading

mav.northwind27-Aug-06 20:21

mav.northwind

27-Aug-06 20:21

Thanks, but the program isn't meant to do anything productive, it's just to show the need for synchronization.
The timing test was just a test to find out what to expect when I run my multithreading applications on a dual-core machine and I was quite surprised that the test doesn't run as fast on a dual-core as it would on a single core...

Regards,
mav

--
Black holes are the places where god divided by 0...

Re: Timing question with multithreading

leppie27-Aug-06 20:11

leppie

27-Aug-06 20:11

Locking a static object mite help...

xacc.ide-0.2.0.57 - now with C# 2.0 parser and seamless VS2005 solution support!

Re: Timing question with multithreading

mav.northwind27-Aug-06 20:25

mav.northwind

27-Aug-06 20:25

Thanks, leppie, I'll try this.
Initially I had 2 objects for locking (non-static), one for each loop.
Then I locked both loops with the same object and then with this.
The strange thing was that using 2 objects also slowed down the program, while using a single locking object or this yielded equal (and better) results.

I'll post an update here as soon as I tried the static object for locking...

Regards,
mav

--
Black holes are the places where god divided by 0...

Re: Timing question with multithreading

mav.northwind27-Aug-06 22:51

mav.northwind

27-Aug-06 22:51

Hi!

The update I promised earlier:
Using a static object vs. an instance object doesn't show any difference.
Still letting the application run on both cores is slower than when limiting it to just one core...

Regards,
mav

--
Black holes are the places where god divided by 0...

Re: Timing question with multithreading

leppie27-Aug-06 23:17

leppie

27-Aug-06 23:17

You are probaby not doing enough work per thread to justify multi threading it. IOW the lock construct is alot more expensive than say an increment statement.

xacc.ide-0.2.0.57 - now with C# 2.0 parser and seamless VS2005 solution support!

Re: Timing question with multithreading

mav.northwind28-Aug-06 4:10

mav.northwind

28-Aug-06 4:10

Could be, yes. I'll try adding a little workload to the locked area...

Thanks,
mav

--
Black holes are the places where god divided by 0...

Re: Timing question with multithreading

mav.northwind28-Aug-06 9:40

mav.northwind

28-Aug-06 9:40

Final update:
You were right. As soon as I let the critical section perform something more demanding the execution times with 2 cores became better than with just one core.

I was really starting to get worried, you know?

Wink | ;)

Thanks!

Regards,
mav

--
Black holes are the places where god divided by 0...

Passing Delegate as a prameter in Method Call

t4ure4n27-Aug-06 3:48

t4ure4n

27-Aug-06 3:48

Hello Every 1, I have a problem where I have to pass a delegate as a parameter to a Method Call (method is simply a caller for an API method). I have decelared and initilized the delegate globally, given it my own method that should be called. I even assigned the delegate to the GCHandle and Pinned it (GCHanle.KeepAlive(....))

Now the problem the delegate is called as a parameter in a method call

The delgate signature is

public delegate void delegateCallBackFunction(); (global 4 namespace)<br />
<br />
public delegateCallBackFunction CallBackFunction; (global 4 class)

..............Now the function where the delgate is called........

public bool wrg303_CodecStart(int hRadio, FileStream ifFileStream, GCHandle targetHandle)<br />
{<br />
ifFileWriter = new StreamWriter(CallbackContextObject.ccifFile);<br />
bool status = true; <br />
status =  (CodecStart(hRadio,  CallBackFunction(GCHandle.ToIntPtr( targetHandle)),GCHandle.ToIntPtr( targetHandle)));<br />
return status; <br />
targetHandle)));<br />
}

If i use this code the error is that The second parameter is void where it should be a delegate.

I can't use new delegateCallBackFunction(.....)
How the hell I am going to pass the delegate as a prameter.

Thanks

o O º(`'·.,(`'·., ☆,.·''),.·'')º O o°
»·'"`»* *☆ t4ure4n ☆* *«·'"`«
°o O º(,.·''(,.·'' ☆`'·.,)`'·.,)º O o°

Re: Passing Delegate as a prameter in Method Call

Nader Elshehabi27-Aug-06 6:00

Nader Elshehabi

27-Aug-06 6:00

Hello

Your code is a bit mixed up. You should have posted the prototype of CodecStart() and CallBackFunction() functions. Anyway, I've revised the sample code in MSDN writen in the GCHandle class example. Did you revise it?

Also you gave targetHandle twice, to the API and to your method, why?

Also Why can't you use new delegateCallBackFunction??

Regards

refresh web page automatically

Mohammad Daba'an26-Aug-06 23:14

Mohammad Daba'an

26-Aug-06 23:14

hello, How can i let the web page to be updated automatically every 10 seconds without forcing the user to press F5 or click refresh button.

I want it as you can see on the gmail page

Thanks alot
Hamody

Re: refresh web page automatically [modified]

Guffa26-Aug-06 23:52

Guffa

26-Aug-06 23:52

or

Or use one as a backup for the other, at 15 seconds or so.

-- modified at 10:10 Sunday 27th August, 2006

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Re: refresh web page automatically

Mohammad Daba'an27-Aug-06 3:57

Mohammad Daba'an

27-Aug-06 3:57

hi, thanks a lot for your reply,...

may u tell me please how i can use the code the u replied me, and where i have to put it??

Thanks alot
Hamody

Re: refresh web page automatically

Guffa27-Aug-06 4:10

Guffa

27-Aug-06 4:10

The meta tag goes inside the head tag.

The body tag, well... where do think that goes? Wink | ;)

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