C / C++ / MFC

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Re: Outlook-like menu control Dominik Reichl22-Aug-02 6:11 Dominik Reichl 22-Aug-02 6:11  Thank you very much!!! Exactly what i needed! I only looked in the controls section of CodeProject, but never looked in the WTL section. Thanks again! Dominik DLL's, the Heap, and CDocument makom4220-Aug-02 21:55 makom42 20-Aug-02 21:55  Having just resolved my plugin problems I now face the challenge of allowing my plugins to manipulate the data in my MFC app's CDocument derived class. This I have done by passing a pointer to my derived doc class to the dll, and everything works fine. The plugin is able to create data in the doc. However, when the doc deletes its data (OnNew... etc) I get a fatal exception. The object it is trying to delete is valid and does exist - however I beleive that it has been allocated from a different heap (the dll's) meaning the app/doc cannot unallocate it from it's own. My dll "creates" data through the document itself.. ... pDoc->CreateVertex() ; ... so why isn't the construction taking place from the "document" heap? I guess it always takes place in the local heap? I could resolve this by getting the dll to track every single thing it creates and releasing it all on destruction, but that is far too clumsy. This must be resolvable - otherwise no-one would have every been able to code plugins with MFC apps... Any ideas? Re: DLL's, the Heap, and CDocument Lakitu20-Aug-02 23:21 Lakitu 20-Aug-02 23:21  Try using AFX_MANAGE_STATE in every function that uses MFC. Usually just put AFX_MANAGE_STATE(AfxGetStaticModuleState()) as the first line in every function. Look! They have the Internet on computers now! (Homer J. Simpson) Re: DLL's, the Heap, and CDocument makom4221-Aug-02 3:16 makom42 21-Aug-02 3:16  Already am - this isn't the problem. (at least afaik! ) Re: DLL's, the Heap, and CDocument Tomasz Sowinski21-Aug-02 0:45 Tomasz Sowinski 21-Aug-02 0:45  makom42 wrote: however I beleive that it has been allocated from a different heap (the dll's) meaning the app/doc cannot unallocate it from it's own. Exactly. The common cure for this problem is implementing your plugins as 'MFC extension' dlls. They'll be using the same heap and global MFC state. Tomasz Sowinski -- http://www.shooltz.com "Yields falsehood when preceded by its quotation" yields falsehood when preceded by its quotation. Re: DLL's, the Heap, and CDocument makom4221-Aug-02 3:21 makom42 21-Aug-02 3:21  Any idea how much extra effor this is going to be? I guess it's not going to be as simple as setup a project as MFC extension DLL, add my plugin files and recompile :S Re: DLL's, the Heap, and CDocument Tomasz Sowinski21-Aug-02 3:25 Tomasz Sowinski 21-Aug-02 3:25  When you create new MFC .dll project, the wizard gives you choice of 'mode'. You should use 'MFC Extension' dll. Basically, the extension needs special DllMain (which wizard generates for you) and _AFXEXT symbol in defines. I'd create new dll and add files. Just ensure that main .exe uses MFC in .dll. Tomasz Sowinski -- http://www.shooltz.com "Yields falsehood when preceded by its quotation" yields falsehood when preceded by its quotation. Re: DLL's, the Heap, and CDocument Roger Allen21-Aug-02 1:41 Roger Allen 21-Aug-02 1:41  As long as every DLL and the EXE links to a shared MFC DLL, then the EXE and DLL's can delete data allocated by eath other without any problems. Roger Allen Sonork 100.10016 I think I need a new quote, I am on the prowl, so look out for a soft cute furry looking animal, which is really a Hippo in disguise. Its probably me. Re: DLL's, the Heap, and CDocument makom4221-Aug-02 3:19 makom42 21-Aug-02 3:19  Both app and .dll's use MFC in a shared DLL... no joy... Custom databases and file storage alex.barylski20-Aug-02 21:42 alex.barylski 20-Aug-02 21:42  I've contemplated using DB's but have decided not to bother becuz I like a challenge, actually I could prolly do with out that one (I don't know of any *free* db's...even mySQL requires money when used for commercial purposes) but still. Anyways the question... When you run a SQL insert on a database with say 100,000 records does the db engine ( at the lowest level) open the file make room in the file insert the item and perform/adjust all previous offsets to their new required values...??? This doesn't make sense...but neither does cacheing 100,000 items [1024 each] in in memory and calculating offsets as you save the file...??? Does a database keep it's records in sequential order for random access or is it more like a linked list so not a heck of alot of possible offset calculations have to be performed...??? Thanx in advance! Cheers! "An expert is someone who has made all the mistakes in his or her field" - Niels Bohr Re: Custom databases and file storage Tomasz Sowinski21-Aug-02 0:23 Tomasz Sowinski 21-Aug-02 0:23  Hockey wrote: Does a database keep it's records in sequential order for random access or is it more like a linked list so not a heck of alot of possible offset calculations have to be performed...??? Database is free to keep the records in any order. It may add your records at the end of the file, it may use empty spaces from deleted records. I'm pretty sure db engines don't move records, as long as you don't defragment. If your app requests particular order with 'ORDER BY' clause, database will use index if possible; if there's no index it'll sort records on the fly (which may take long time if there's lot of data - that's why you should use index). Tomasz Sowinski -- http://www.shooltz.com "Yields falsehood when preceded by its quotation" yields falsehood when preceded by its quotation. Re: Custom databases and file storage alex.barylski21-Aug-02 1:08 alex.barylski 21-Aug-02 1:08  Tomasz Sowinski wrote: Database is free to keep the records in any order. It may add your records at the end of the file, it may use empty spaces from deleted records. I'm pretty sure db engines don't move records, as long as you don't defragment. Interesting... Do you know of any resources where I might learn about the whole process...? Anything but open source like mySQL...i don't wanna read 10000's of lines of code to figure how it all works... Thanx! "An expert is someone who has made all the mistakes in his or her field" - Niels Bohr Re: Custom databases and file storage Tomasz Sowinski21-Aug-02 1:16 Tomasz Sowinski 21-Aug-02 1:16  http://msdn.microsoft.com/library/default.asp?url=/library/en-us/architec/8_ar_da_7v1h.asp[^] Tomasz Sowinski -- http://www.shooltz.com "Yields falsehood when preceded by its quotation" yields falsehood when preceded by its quotation. Re: Custom databases and file storage Steven Gregg21-Aug-02 0:30 Steven Gregg 21-Aug-02 0:30  Whaddya mean no free? Try writing some code using ADO and you'll have a free DB? Re: Custom databases and file storage alex.barylski21-Aug-02 1:04 alex.barylski 21-Aug-02 1:04  What about distributing DLL's or drivers and such...? Do you need permission from MS or anything first...? I'm really looking for RDBMS source code you can just compile into your existing source...no need for third party files... Cheers "An expert is someone who has made all the mistakes in his or her field" - Niels Bohr Re: Custom databases and file storage Steven Gregg21-Aug-02 1:17 Steven Gregg 21-Aug-02 1:17  Well I used DAO which generates MS Access style databases. The dll's or whatever is uses are all part of the Win32 API. This was succeeded by ADO which generates MS SQL style databases. I dunno if there's any newer API's that Microsoft recommends (maybe CDO ??)...databases aren't really my thing. The DAO stuff is well documented though. Re: Custom databases and file storage Tomasz Sowinski21-Aug-02 1:16 Tomasz Sowinski 21-Aug-02 1:16  Steven Gregg wrote: Well I used DAO which generates MS Access style databases. The dll's or whatever is uses are all part of the Win32 API. No, it's not. Tomasz Sowinski -- http://www.shooltz.com "Yields falsehood when preceded by its quotation" yields falsehood when preceded by its quotation. Re: Custom databases and file storage Joel Lucsy21-Aug-02 12:32 Joel Lucsy 21-Aug-02 12:32  I think you need to look at http://www.hwaci.com/sw/sqlite/[^] Excellent stuff, completely free, source included. Joel Lucsy (jjlucsy@ameritech.net) images with different height in CTreeCtrl Jaro20-Aug-02 21:31 Jaro 20-Aug-02 21:31  Is there a way to use images with different height in CTreeCtrl? Re: images with different height in CTreeCtrl Tomasz Sowinski20-Aug-02 23:27 Tomasz Sowinski 20-Aug-02 23:27  No, when they come from image list. You'd have to use custom draw. Tomasz Sowinski -- http://www.shooltz.com "Yields falsehood when preceded by its quotation" yields falsehood when preceded by its quotation. If my app use DirectShow, do my mp need DirectX for running? sonshiro20-Aug-02 19:58 sonshiro 20-Aug-02 19:58  My application use DirectShow. I want to know that wether my app need DirectX for execute. Thank you. Re: If my app use DirectShow, do my mp need DirectX for running? Stephane Rodriguez.20-Aug-02 21:30 Stephane Rodriguez. 20-Aug-02 21:30  Didn't you answer your own question ? To know what DLLs you need, just launch your app, and use one the tools provided along with VS : DLL dependency walker. You'll certainly see directx dlls. DLL dependency walker is a static logger though, if you want to know dynamically which DLLs are loaded, then I recommend a far better tool : Christophe Nasarre's article on DLL hell, And I swallow a small raisin. Help! answer to simple question: System.IO.Stream?? devvvy20-Aug-02 18:56 devvvy 20-Aug-02 18:56  QUESTION: I still cant figure out what the heck is stream (System.IO.Stream) and what we need it for? i'm a C++ user. If i need to store ANYTHING, whether it's a simple "double" or as complex as an array of CMyFunnyImage, i can always allocate a buffer: unsigned char * pbuffer = new char [100]; i'm a bit newbie, but why do we need to serialize anything to a "stream"?? The following fragment serialize an xml document to a "MemoryStream". But i dont see why it didnt just serialize it to a "String" or a generic buffer "unsigned char"?? Sample code fragment, in VB.NET: Dim HSBCWC As new Customer() HSBCWC.ID = 08346 HSBCWC.FirstName = "Paul" HSBCWC.LastName = "Bowie" ... Dim stream As MemoryStream() Dim serializer As New XmlSerializer( Customer.GetType() ) serializer.Serialize( stream, HSBCWC ) QUESTION 1: Why not serialize to a string as supposed to a MemoryStream? It would be much simpler rite? ... stream.Flush() QUESTION 2: I dont understand why we need to flush? flush what from what? I thought HSBCWC has already been "flushed" to stream? stream.Seek(0,SeekOrigin.Begin) however, I do understand why u need to Seek (rewind the stream). ... Dim reader As New StreamReader(stream) message.body = reader.ReadToEnd() stream.Close() SmptMail.Send(message) I'm a newbie and pretty confused why we need "streams" in general. And i could find any decent explaination from MSDN (as usual). norm WM_COMMAND custom message ID JennyP20-Aug-02 18:58 JennyP 20-Aug-02 18:58  Hello, I would like for my DialogBar class to update all it's values from my CDocument class. I've been told I need to add a new command ID and use WM_COMMAND. I know how to set up the DialogBar side of things, but I don't know how to send the command from the CDocument class. Any help or pointers to articles? thanks! JennyP Re: WM_COMMAND custom message ID alex.barylski20-Aug-02 19:21 alex.barylski 20-Aug-02 19:21  To send a WM_COMMAND message to your dialog bar object I think it would look something like: // Somewhere inside CDocument ((CMainFrame*)AfxGetMainWnd())->m_MyDlgBar.SendMessage(WM_COMMAND); "An expert is someone who has made all the mistakes in his or her field" - Niels Bohr

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