I need to detect when another application /window in my app does paste on my previously set data , so I can remove it from my source window. I have discovered that COleDataSource::DelaySetData theoretically does this and COleDataSource::OnSetData would get called when paste occurs, but I can not be sure. MSDN is (as usually) vague about this matter and does not clearly say one way or the other.I will be using an custom format and watever format is explorer using for cut/paste files.
So the question is how EXACTLY (not theoretically) can this be done.
I really need to remove the items from my window if and only if they are pasted somewhere else.
You're doing it all wrong. When you Cut something it's supposed to be deleted immediately, and you should provide an undo function if it needs to be restored.
The clipboard was not designed for bidirectional signalling. DelaySetData is intended for applications which are submitting large amounts of data in different formats, so that they only need to provide the format which is required by the receiver; using it to detect when a paste occurs is relying on a side effect. There are clipboard managers which might make this fail.
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I'm trying to make an application which to manage information about several providers.
Target system is windows and I'll be coding with c++.
The users are not expected to be handy on anything related to computers, so I want to make it as fool-proof as possible. Right now my objective is to distribute only an executable, which should store all the information they introduce in there.
Each user stores information of their own providers, so I don't need the aplication to share the data with other instances. They do upload the information into a preexisting system via csv, but I can handle that easily.
I expect them to introduce new information at least once a month, so I need to update the information embedded. Is that even possible? Making a portable exe and update its information? So far the only portable apps I've seen which allow saving some personification do so by making you drag files along with your exe.
I try to avoid SQL to avoid compatibility problems (for my own applications I use external TXTs and parse the data), but if you people tell me it's the only way, I'll use sql.
I've seen several other questions about embedding files, but it seems all of them are constants. My files need to be updatable
Thanks in advance!
Edit: Thanks everyone for your comments. I've understood that what I want is not worth the problems it'd create. I'll store the data separatedly and make an effort so my coworkers understand what's the difference between an executable and it's data (just like explaining the internet to your grandma's grandma...)
While I wouldn't go as far as to say that it's impossible, it will definitely be neither simple nor pretty nor something anyone should ever recommend doing.
The basic problem is: While your .exe is running, the .exe file is mapped into memory and cannot be modified. Now, one thing you could do is have your .exe, when it's started, create a temporary copy of itself somewhere, start that one, tell the new process where the original image is located (e.g., via commandline arguments), and then have the original exit. That temporary copy could then modify the original image. To put data into your .exe, you can either use Resources, or manually modify the PE image, e.g., using a special section created inside the image to hold your data. You can also simply append arbitrary data at the end of an .exe file without corrupting it.
However, I would like to stress again that I do not recommend actually doing stuff like that. I would simply store data in separate files. If your users are familiar with Excel, then they should be familiar with the idea that data is stored in files…
Vista introduced an interface: IFileDialog::SetFilter, which allows me to setup a filter that will be called for every potential filename to see if it should be shown to the user.
Microsoft removed that in Windows 7, and didn't support it in XP.
I am trying to customize the our Open file dialog so that I can control which files are displayed to the end user. These files are marked internally with a product-code - there isn't anything in the filename itself to filter on (hence file extension filters are not useful here -= I need to actually interrogate each one to see if it is within the extra filter parameters that our users specified).
I would guess that Microsoft removed the SetFilter interface because too often it was too slow. I can imagine all sorts of similar ideas to this one which don't scale well for networks and cloud storage and what have you.
However, I need to know if there is an alternative interface that accomplishes the same goal, or if I really am restricted to only looking at the file extension for filtering purposes in my File dialogs?
Follow-up:
After looking further into CDN_INCLUDEITEM, which requires the pre-vista version of OPENFILENAME, I have found that this is the most useless API imaginable. It only filters NON-filesystem objects. In other words, you can't use it to filter files. Or folders. The very things one would filter 99.99% of the time for a file open or save dialog. Unbelievable!
There is a very old article by Paul DiLascia which offers the technique of removing each offending filename from the list view control each time the list view is updated.
However, I know from bitter experience that the list view can update over time. If you're looking at a large folder (many items) or the connection is a bit slow (heavily loaded server and/or large number of files), then the files are added to the dialog piecemeal. So one would have to filter out offending filenames repeatedly.
In fact, our current customized file open dialog uses a timer to look at the view's list of filenames periodically to see if any files of a given pattern exist, in order to enable another control. Otherwise it's possible to check for the existence of these files, find none, but a moment later the view updates to have more filenames, and no events are sent to your dialog to indicate that the view has been changed. In fact, my experience with having to write and maintain code for the common controls file dialogs over the years has been that Microsoft is not very cluefull when it comes to how to write such a thing. Events are incomplete, sent at not-useful times, repeated when not necessary, and whole classes of useful notifications don't exist.
Sadly, I think I might have to give up oh this idea. Unless someone has a thought as to how I might be able to keep up with the view spontaneously changing while the user is trying to interact with it (i.e. it would be awkward to go deleting out entries from the list view and changing the user's visual position, or highlighted files, or scroll position, etc.)
You need to initialise the callbacks for your CFileDialog. Then you need to process CDN_INCLUDEITEM notification code to include or exclude items.
You can also check this great article. The author uses some other approaches in addition to callbacks
As you have already discovered, starting in Windows 7 it is no longer possible to filter out files from being displayed based on content, only file extension. You can, however, validate that the user's selected file(s) are acceptable to you before allowing the dialog to close, and if they are not then display a message box to the user and keep the dialog open. That is the best you will be able to do unless you create your own custom dialog.
We're using MFC data exchange to validate some data and we're having some problems. We're using the DDV_MinMaxFloat call to ensure that edit boxes in various parts of the application contain floating point numbers within a specified range. When using this validation if a value is entered out of range a dialog is automatically displayed to the user indicating that the value must lie within the range specified. This has been working correctly whilst running the application in debug however when building a release we are getting problems. The validation is still performed in release mode however the message box displayed to the user is blank.
I've tried the usual forcing a rebuild, deleting old resource files and deleting precompiled header files but this continues to happen in release mode. Has anyone come across this before? Are there any obvious things to look for?
I should also add that this application is over 10 years old, so obviously has been working correctly before. Somehow something has gone wrong in the last few weeks to cause this.
Those messages will come from MFC's resource strings. There might be some conflict with your own resources. Check to make sure your resources adhere to Microsoft's guidelines TN020: ID Naming and Numbering Conventions.
Pay particular attention to this bit:
MFC's internal framework implementations reserve two ranges: 0x7000
through 0x7FFF and 0xE000 through 0xEFFF.
Somehow something has gone wrong in the last few weeks to cause this.
Since your application worked fine a few weeks ago, it should be easy: check out the last working version from your revision control system and compare it with the current version. Or try to narrow it down to the first revision which does not work any more.
Check with Spy++ if there are controls on the message box that is displayed and if the text on them is blank, or if there's no controls on them at all. If the text is empty, you'll have to check the resources or the way the messagebox is called/created. Otherwise it may be something like resource being set incorrectly and the message assuming it can read its resource strings from ::AfxGetResourceHandle(). Note that this is a very easy error to make - it's a global handle that can be changed everywhere (including in dll's that you have no control over) so changes in remote parts of the code that at first sight seem unrelated may trigger it.
I tried to write a program for safe deleting files. However, I have a problem with deleting system files (recycle bin etc.). Now my question is. Which way to hidden files (from users) at this dialog. Other files I add to listview and then rewrite them zeroes. After that I delete this files without recycle.
The only way guaranteed to do this is to write your own open file dialog. But I'd advise that you find a better way of doing this, since that's considered pretty bad form.
It just occurred to me, but what you could do (and I'm not saying it's easy or nice) is launch the open file dialog, then using the handle to the window gain access to the listbox, and manually remove any system files from that list per your own heuristics. It should work, but I can't guarantee that the items will remain removed (i.e. I think Windows will auto-refresh every so often), so you'll have to experiment and YMMV.
Bottom line: find a different way of preventing the user from selecting them. Like Mat says, perhaps just give a message and leave it at that. Failing that, write your own dialog (yuck!).
I'm looking for a good efficient method for scanning a directory structure for changed files in Windows XP+. Something like how git does it is exactly what I'm looking for, when running a git status it displays all modified files, all new (untracked) files and deleted files very quickly which is exactly what I would like to do.
I have a basic model up and running which performs an initial scan and stores all filenames, size, dates and attributes.
On a subsequent scan it checks if the size, attributes or date have changed and marks as a changed file.
My issue now comes in detecting moved and deleted files. Is there a tried and tested method for this sort of thing? I'm struggling to come up with a good method.
I should mention that it will eventually use ReadDirectoryChangesW to monitor files and alert the user when something changes so a full scan is really a last resort after the initial scan.
Thanks,
J
EDIT: I think I may have described the problem badly. The issue I'm facing is not so much detecting the changes - I have ReadDirectoryChangesW() using IOCP on multiple threads to detected when a change happens, the issue is more what to do with the information. For example, a moved file is reported as a delete followed by a create and a rename comes in 2 parts, old name, followed by new name. So what I'm asking is how to differentiate between the delete as part of a move and an actual delete. I'm guessing buffering the changes and processing batches would be an option but feels messy.
In native code FileSystemWatcher is replaced by ReadDirectoryChangesW. Using this properly is not simple, there is a good baseline to build off here.
I have used this code in a previous job and it worked pretty well. The Win32 API itself (and FileSystemWatcher) are prone to problems that are described in the docs and also discussed in various places online, but impact of those will depending on your use cases.
EDIT: the exact change is indicated in the FILE_NOTIFY_INFORMATION structure that you get back - adds, removals, rename data including old and new name.
I voted Liviu M. up. However, another option if you don't want to use the .NET framework for some reason, would be to use the basic Win32 API call FindFirstChangeNotification.
You can use USN journaling if you are up to it, that is pretty low level (NTFS level) stuff.
Here you can find detailed information and source code included. It is written in C# but most of it is PInvoking C/C++ functions.