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hi,
How to use lParam and wParam to send values to message queue?
Examples are welcomed.
Thank u in advance.
Extreme programming. Do the No.1
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I believe wParam and lParam are both 32 bit types. To use them you can cast any data type that is 32 bits or smaller to either lParam or wParam and past them as arguments to the ::PostMessage() function.
Example:
<br />
CObject *pObj = new CObject();
<br />
::PostMessage(hWnd,MESSAGE_ID,(WPARAM)pObj,NULL);<br />
Then handle the message in the window that recievies it by declaring it in the message map and writing a function to handle the message.
<br />
ON_MESSAGE(MESSAGE_ID,OnMessage)<br />
<br />
LRESULT CSomeClass::OnMessage(WPARAM wParam, LPARAM lParam) {<br />
CObject *pObj = (CObject *)wParam;<br />
}<br />
Note: none of the code is tested and written off the top of my head.
- Anatari
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As Anatari said, you can cast any 32-bit value that you would like to fit inside of wParam and lParam. However there are a few things to be aware of.
If you are posting a message to the message queue, then you cannot use objects that were created on the stack. That is because these objects will most likely be destroyed before the posted message is processed. Instead you will need to create a mechanism to allocate the object on the heap, and destroy the object after the message has been processed.
If your item is being sent to the message queue, it will be safe to pass items that are located on the stack.
Build a man a fire, and he will be warm for a day
Light a man on fire, and he will be warm for the rest of his life!
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stack vs heap
good point =)
norm
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I am writing a MFC MDI application. At a particular point I am displaying a Dialog in a separate thread that contains a progress meter. I am using the AfxBeginThread function supplying the CRuntimeClass of the progress meter dialog. Then when the progress meter is no longer needed I call the dialog's EndDialog function and then call WaitForSingleObject to wait until the thread is terminated.
All well and good...It works just fine under Win98.
It doesn't work under Win2K 
It seems that under NT in order to use WaitForSingleObject, the SYNCHRONIZE permission has to be set...which is also accomplished by setting PROCESS_ALL_ACCESS permissions.
Finally, my question. How do you set the SYNCHRONIZE or PROCESS_ALL_ACCESS permissions for the process in a MFC MDI app?
Gary Kirkham
A working Program is one that has only unobserved bugs
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I strongly doubt that your problem has to do with events permissions. More likely it stems from the fact that you're calling EndDialog in a strange fashion (maybe directly from the main thread). The proper way to close the dialog is by sending a WM_CLOSE message: try this, maybe your problem goes away.
Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo
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Thanks that did the trick
Gary Kirkham
A working Program is one that has only unobserved bugs
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Sometime some pages is very nice, but I want comment it. Can I write some tools just paint on IE or web control ? Pz give some hints . THX.
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Use dhtml edit controls. (separate SDK from the platform SDK, or CHtmlEditView added in MFC7/VC7).
How low can you go ?
(MS rant)
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Thx very much.....
I will try dhtml edit controls. Do you have some examples for me? Thx again.
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I have seen at least one on CP. Use the search engine (CHtmlEditCtrl, CHtmlEditView, CDHtmlDialog).
And you have two samples along with the VC++.NET DVD : dhtmlexplore, and htmledit. May be those are available online as well, I haven't checked.
Strongly suggested is a lookup in MSDN mag archive. Pretty sure you'll have decent listings (esposito and other guys are fond of that).
How low can you go ?
(MS rant)
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O... I use VC6. So I have no .NET DVD. I find all examples are for VC7. When I use DHTML Edit Control, it always show office 2000 install message? Why ?
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The Office message is because 2 years ago the dhtml edit component was installed along with all MS products, so i guess you have some registry keys out there attaching it to Office (you should know that the Office installer is a total mess by the way).
More info about the component here[^].
As the documentation says, MS regards it now as legacy as they are willing to sell VC7 and .NET stuff. It is obvious there are dollars here, than with just a tiny stand-alone SDK. Business as usual...
How low can you go ?
(MS rant)
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How do i display filenames and their icons in a Listbox?
Right now my app has all CListbox but let me know if I should change them to CListCrtl if it would be easier to display.
I tried searching for this information but I could not find. I understand people have created Classes out there to do this but I would like to just to it using CListbox or CListCtrl, unless it would be easier using an easily "plugable" Class.
I only need the code for the creation of the Listbox or control since I have the code to get the filename and their paths already finished.
Thanks,
Joe
www.joeswammi.com
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A Listctrl would be a better choice since it supports images while CListBox doesn't. You can get the image of a file by using SHGetFileInfo - this can return the icon of the given file. Remember to use the flag SHGFI_USEFILEATTRIBUTES if the file in question isn't an executable file to avoid hitting the disk for each file displayed.
PJ Naughter has an excellent demo at http://www.naughter.com/filetreectrl.html[^] - you might want to use it as a base for your code.
Wenn ist das Nunstück git und Slotermeyer? Ja! Beierhund das oder die Flipperwaldt gersput!
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Thanks I will check it out. Shortly after posting my question I finially found something http://codeguru.earthweb.com/imagelist/DirIconExample.html
If you have time check that out and let me know what you think, just off hand it looks like PJ's is more powerfull but I really havent looked at it yet
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Hi.
Okay. I am considering Overlapped I/O and Completion Port I/O models as more robust non-blocking I/O for a Winsock program. Currently I use WSAAsyncSelect. I have some essential questions about the two I/O model.
- Overlapped I/O
Okay. I understand Overlapped I/O with respect to both the event and completion routine. I believe that a primary reason that the completion routine solution of an Overlapped I/O model is more powerful that the event solution is simplicity. For example, the event solution is limited to 64 sockets per worker threads.
Under both solutions and especially the completion routine, how do you associate the socket that caused the overlapped I/O to call the completion routine? In other words, let say socketXYZ triggered overlapped I/O to call its completion routine function. How do you determine inside the routine function that is performing send, recv, etc. on socketXYZ?
- Completion Port I/O
This is really a powerful I/O model and is hands down the best I/O model under NT and newer versions of Windows. I have three essential questions.
1) Lets say there are exactly ten active sockets associated with a completion port. As each socket become inactive via user disconnect, error, etc., how do you know when there are no sockets (zero socket) associated with the completion port? In other words, if you wanted to close a completion port when no socket is associated with it, How do you know when there is no socket associate with it?
2) Given that the call to GetQueuedCompletionStatus() return FALSE (failed), How would you know what sockets to close during cleanup since the completion port had crashed?
-----
Under either Overlapped I/O or Completion Port I/O how do you know when to connect, send, receive, etc. data? For example, in WSAAsyncSelect and WSAAsynEvent, you can can AND check FD_SEND, FD_READ, etc. However, in Overlapped I/O or Completion Port I/O, how do you know if there is data available or when the host/client is ready for you to send data?
Thanks,
Kuphryn
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1) You have to keep track. Obviously, you will need all the socket handles stored somewhere. When you run out of socket handles in your list, you know that the IOCompletionPort no longer has any handles it is waiting on?
2) Again, you have to keep a list of socket handles.
My idea would be to create a Connection Manager, that maintains a list of connections (a class that would encapsulate the state of each socket connection, with the socket handle as a member). The pointer to the connection object can be the key on the IOCompletion Port. So, when the IOCompletion Port returns, you have the connection object along with it. Note: You may want to use some other key mechanism (other than using a pointer) because the key variable in the IOCP API is a DWORD and can cause problems when Windows becomes 64 bit.
If the IOcompletionPort crashes, you have to call a cleanup on the connection manager, which will inturn destroy all connection objects, and you can call closesocket in the destructor.
I could not find any API call that gives a list of sockets associated on the IOCP.
Hope this helps.
Thomas
modified 29-Aug-18 21:01pm.
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Thanks.
Your solution is very similar to the solution I current use for WSAAsyncSelect. I stored a socket object in a linked list.
Okay. Sounds like I will need to design a socket object for the Completion Port I/O.
Kuphryn
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Hello,
I have a toolbar and I have the buttons set to "check" style so when they are pressed they stay down and the pressed again they pop back up.. the problem is that I change the image depending if the button is up or down.. I do the following to change the image.. the problem is the GDI Objects keep climbing and climbing and climbing every time i push the button.. I would assume this is a bad thing.
Am I doing any thing wrong??
// Set up image lists.
CImageList imageList;
CBitmap bitmap;
// Create and set the toolbar image list.
bitmap.LoadBitmap(IDB_UNSECURE);
imageList.Create(16, 16, ILC_COLORDDB|ILC_MASK, 3, 1);
imageList.Add(&bitmap, RGB(255,0,255));
m_wndFormatBar.SendMessage(TB_SETIMAGELIST, 0, (LPARAM)imageList.m_hImageList);
imageList.Detach();
imageList.DeleteImageList();
bitmap.Detach();
bitmap.DeleteObject();
Any ideas?
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Note from our friends at the MSDN (in the TB_SETIMAGELIST docs):
"Note: Your application is responsible for freeing the image list after the toolbar is destroyed"
I think you also need to delete the bitmap. So, I would suggest this:
CImageList imageList;
CBitmap bitmap;
bitmap.LoadBitmap(IDB_UNSECURE);
imageList.Create(16, 16, ILC_COLORDDB|ILC_MASK, 3, 1);
imageList.Add(&bitmap, RGB(255,0,255));
HIMAGELIST hOldImageList = m_wndFormatBar.SendMessage( TB_GETIMAGELIST, 0, 0 );
m_wndFormatBar.SendMessage(TB_SETIMAGELIST, 0, (LPARAM)imageList.m_hImageList);
imageList.Detach();
imageList.DeleteImageList();
ImageList_Destroy( hOldImageList );
bitmap.DeleteObject();
Chris Richardson
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I see exactly what your trying to do, pull the old image list and destroy it.. for some reason I can't do a HIMAGELIST blah = m_wndFormatBar(...) it says cant convert from a hImage to a long.. (or something like that) I just tried a few things real quick last night but didnt have time to do any further testing..
Thanks for the idea, I'm sure I'll get it figured out.
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Sorry, I never actually built the code. You'll need to do a cast.
HIMAGELIST blah = (HIMAGELIST)m_wndFormatBar.SendMessage( TB_GETIMAGELIST, blah, blah );
Chris Richardson
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I think from memory that imageList.Add makes a copy, in which case your bitmap.Detach is a memory leak.
Christian
No offense, but I don't really want to encourage the creation of another VB developer. - Larry Antram 22 Oct 2002
Hey, at least Logo had, at it's inception, a mechanical turtle. VB has always lacked even that... - Shog9 04-09-2002
During last 10 years, with invention of VB and similar programming environments, every ill-educated moron became able to develop software. - Alex E. - 12-Sept-2002
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