ListBox problem

[kingslee]

Hello friends,
I create ListBox using MFC, in which I want to display the Output (like Visual c++ IDE debug windowor Output window).
I create a button after that it starts processing and ready to display the output.
I used
m_ListBoxResult.AddString(strlineCount); like that for all the functions and so on.. there will be lot of output.

Everything works fine but It displays everything after all the process done.
while processing nothing is displayed.

Its not working in runtime. Hope I perfectly project my question.

If anybody needs the code , I will attach them

forexample:

CFinderView::Onbuttonclick()
{

PrintSystemUsage();

ReadFiles();
}
void PrintSystemUsage()
{
m_ListBoxResult.AddString("Crawling the Tree....");
strlineCount ="something";
m_ListBoxResult.AddString(strlineCount);

}

and in each function i have hundreds of output. I used only AddString().. with UpdateData(false).
But the List Box displays only after finishing Read Files.

Looking forward to your reply.

thnx in advance .

mfg,
kingsly

[junma]

i think you could sendmessage with paramter "LB_INSERTSTRING",
and count index correctly

[PadexArt]

Adding a string into the listbox means a message is sent to the listbox. To see the change the window holding the listbox needs to refresh itself and allow the listbox to to the same.

But with this algorithm you are using the application's main thread ( the UI thread) is blocked in the Onbuttonclick function so no message gets processed until the function finishes.

You have 2 options:
1. the nice way: use a thread to do the file processing and from that thread sent messages to the UI thread to add strings into the listbox
2. the old way: process the window messages yourself. See this article for more details

[kingslee]

thnx PadexArt and Junma for your replies.

PadexArt , I will try out ur nice way hint.

I am gonna do thread for the first time and its really interesting .

Get back to you, if i have a serious problem.

once again thanks

mfg,
kingsly

[VictorN]

......
and in each function i have hundreds of output. I used only AddString().. with UpdateData(false).
But the List Box displays only after finishing Read Files.

1. The UpdateData(false) call is not needed here, moreover, it only slows the apllication performance down - remove this line.
2. The problem List Box does not display until finishing Read Files is because the CPU is busy reading the files - there is no time to update the GUI. To solve this problem you could create a worker thread and move all "Read Files" operations to it, then PostMessage a user defined message from a worker thread to the View window with some data to update the GUI. Tke a look at this article: WorkerThreads

3. to junma: sendmessage with paramter "LB_INSERTSTRING" is the same as callinf CListBox::InsertString - the same as CListBox::AddString (minus sorting, plus setting the position in list box).

PS. PadexArt was about 20 minutes faster!

[kingslee]

Hallo PadexArt,
I use seperate thread for all my function. Inside these functions, I need to use this Listbox control right. But these member variables are not declared according to the thread and its declared in Form View class.cpp

I include the respective header files to it also.

What is the problem?

pls clarify me.

waiting for your reply

thnx

kingsly

[PadexArt]

POst the code you are using. Even better would be to zip and upload your project.

[VictorN]

Hallo PadexArt,
I use seperate thread for all my function. Inside these functions, I need to use this Listbox control right. But these member variables are not declared according to the thread and its declared in Form View class.cpp
...

Again, check it out: WorkerThreads

[kingslee]

Hi,
I am attaching one I did before and also one with thread.

waitn for your reply

kings

[kingslee]

Thanks VictorN for your reply ..
I just going through the article ..
I used the UI thread in my attached file ..
.. I didnt finish the article .. yet..
get back to you guys .. soon ..
thnx
kings

[krmed]

Another, perhaps simpler solution would be to change your code as shown here in bold:

void PrintSystemUsage()
{
m_ListBoxResult.AddString("Crawling the Tree....");
strlineCount ="something";
m_ListBoxResult.AddString(strlineCount); 
m_ListBoxReslult.UpdateWindow(); 
}

Hope that helps.

[kingslee]

Thanks Krmed+..
It's worked ..

Such a simple solution.

Anyway I really wanna know about UI or Worker Thread implementation.

Looking forward to get reply from PAdexArt and VictorN.

As I read the article , its pretty tricky while dealing with mfc controls like these.

Once again thankyou so much Krmed+

mfg,
kingsly