I m developping a little soft to notify users when they are pasting content in unauthorized applications, i hook the GetClipboardData to do so. Nearly everything is working fine but when i copy content from Word for example, i click on InternetExplorer, i open an explorer window and close it, some GetClipboardData are launched from explorer. Can someone help me to understand that behavior ?
Thanks in advance
Regards
It is common to receive unexpected clipboard events from certain applications, mostly from Microsoft, when you do things like closing windows or doing anything that makes the application stop and think: "hey, maybe I left some crap on the clipboard, I'd better clean it up, maybe re-post it as plain text without the OLE stuff, maybe I already did that, but I can't remember, so I'll do it again." It's a sort of OCD that they build into just about everthing. Sometimes you get a pop-up saying "you've placed a large amount of data on the clipboard, would you like to make it available for other applications" when you quit a program. That's the same thing. Basically, they've put a bunch of formats on the clipboard that would require "delayed rendering" to be pasteable. And now the app is worried about leaving invalid data on the clipboard, so it has to re-post the data without the fancy formats.
You'll also get this if you copy a cell from Excel, and then un-highlight that cell.
If you get a clipboard event when STARTING an app, it's likely an add-in hooking into the clipboard chain, or perhaps committing the worst sin of all: copy/pasting its icon into a toolbar.
Related
In Windows 7(I am not sure about other OS) when you are on a webpage, pressing the space-bar scrolls a few pixels down the page. But when you are in an interface where typing can be done(like an input element, textarea, word editor, code editor, search bar, etc), pressing the space-bar obviously types a space.
Similarly, when all the open windows or menus are minimized, and you are viewing the desktop, and you press a letter key, instead of the letter being typed somewhere, a beep sound is produced.
This shows that the availability of a typing functionality can be "detected". And if it can be detected, it can most likely be done so using C++.
I don't know what to call this. I tried to find out using google but everything I got seemed unrelated to this. I was probably not using the correct keywords.
Whatever this is, I am creating a C++ program where I need to be able to detect it(in an if condition). Something like this
if (/*typing can be done*/) {
//Do something..........
}
Or this
if (/*typing can NOT be done*/) {
if( GetKeyState(VK_SPACE) & 0x8000 ) {
//Do something..........
}
}
And I need to be able to do so natively. Not specific to a particular console window or UI.
If you can help me in any way in figuring this out than please do so. And please feel free to make or suggest relevant edits to improve this question and make it less vague and more detailed and to-the-point.
The functionality you describe belongs to the program running the window with focus, not to the operating system (although the operating system will, at least in part, ultimately power that functionality). It shouldn't come as a surprise that programs can detect keystrokes, because otherwise you wouldn't be able to use your keyboard to input any characters into your computer.
However, you cannot just "detect" a random event with an if statement. "if" is not "when". Your computer will not repeatedly check all if statements in your program and jump to that location in the code whenever one matches. Imagine the chaos!
A program sufficiently complex to have a graphical interface almost certainly has an "event loop", be this in its own code or buried within an API call (as in the case of native Windows applications); such an event loop typically polls for keys being sent to the window(s) managed by the program. If you do not have an event loop (and if your operating system cannot generate a "signal" when a keystroke otherwise goes unhandled), you will have to make one.
Exact specifics are beyond the scope of a Stack Overflow answer, but by pointing you in the direction of a textbook about how to create graphical programs, I am enabling you to discover how input and output is handled in those cases.
I use AVG and it recently detected a virus. It has before ;) but this was the first time I noticed this.
When I went into the folder containing the virus, AVG immediately, automatically, detected the virus without me even clicking on the application. So I though how could it know a virus was there even when I did not even click (single click) on it.
The only possible answer is that it continuously checks the explorer folder location of all windows and scans all the files in the folder. But how does it see what folder is being viewed by me?
Please explain (if possible) with a C program that does what ever AVG did.
Also : I use Windows if that helps.
When you open a folder a bunch of file system operations is executed (you can use tools like FileMon or ProcMon to take a look at this). Your AV software monitors file access.
There are multiple ways to do this monitoring, e.g. Filter Drivers - you can find a great sample at http://www.codeproject.com/Articles/43586/File-System-Filter-Driver-Tutorial
So when you opened the folder, AV software noticed that you opened a directory, consulted its own data, and informed you about the virus.
I say 'consulted its own data', as AV tools usually don't scan files on access - they do it when the files are written to, as it doesn't make sense to scan files which were marked as clean if they haven't changed since the last scan.
Most virus scanners operate on the principle of API hooks/filters. Whenever windows needs to process a command, like opening a folder, clicking a window, executing a file, etc it generates an api call along with some information like the window coordinates clicked, or a string representing a file. Other programs can request a hook into one or more of these functions which basically says 'instead of executing this function, send it to me first, then I might send it back'. This is how many viruses work (preventing you from deleting them, or copying your keystrokes, for example), how many games/apps work (keyboard, joysticks, drag-and-drop), as well as malware detectors and firewalls.
The latter group hooks the commands, checks any incoming ones to see if they're on the level, then either allows them to resume or blocks them. In this example, opening the folder likely triggered a syscall to parse a directory, and the scanner parsed it too (eg 'realtime protection'). To view all of your hookable functions as well as what is using them, google for a free program called 'sanity check' (previously called 'rootkit hook analyzer'). Most of the red entries will be from either windows firewall or avg, so don't worry too much about what you find.
I have written a small program using Borland's C++ builder, and along the way, everything seemed fine. My program has a map window and a table window, and when a user presses a button, a long process is started that reads in all the map and table information and then displays that. Every time i ran it through the debugger, I had no issues. Then today, I decided to test it without running it through the debugger. To my horror, The program reads in the map information and then displays it on the paintbox canvas without a problem, but when it loads the information for the grid, the map gets erased!!! It appears to happen during the load phase for the table. this takes about 4 seconds, and during which time, the window tells me that it isnt responding. This is when the map gets erased. Anyone have any ideas on why this is happening? Its driving me nuts, and I dont really understand whats going on under the hood here.
UPDATE:
I have fixed the problem to some degree. I was poking around and found this: Avoiding "(Not Responding)" label in windows while processing lots of data in one lump
I added the code to run once in the middle of the data read in for the table. this fixed my problems. however, I was wondering if anyone knows why this is the case? why does my program going unresponsive cause my canvases to be erased?
Marcus Junglas wrote a detailed explanation of the problem, which affects both Delphi and C++Builder.
When programming an event handler in
Delphi (like the OnClick event of a
TButton), there comes the time when
your application needs to be busy for
a while, e.g. the code needs to write
a big file or compress some data.
If you do that you'll notice that your
application seems to be locked. Your
form cannot be moved anymore and the
buttons are showing no sign of life.
It seems to be crashed.
The reason is that a Delpi application
is single threaded. The code you are
writing represents just a bunch of
procedures which are called by
Delphi's main thread whenever an event
occured. The rest of the time the main
thread is handling system messages and
other things like form and component
handling functions.
So, if you don't finish your event
handling by doing some lengthy work,
you will prevent the application to
handle those messages.
You can reduce the problem by calling Application->ProcessMessages(), while loading your map data, however I recomend using a separate thread to load the data.
I have never used C++ Builder, but i used Delphi. I think the libraries are the same.
Does that component you use store the image data? It may only draw to the screen. Try covering the window of your app with another window. If it erases it, you have to use a component which stores the image.
See this, it is for Delphi, but it may help. There should be a Image component in C++ Builder. Try using that instead of PaintBox.
You can solve the unresponsivenes problem by running the time consuming task in a separate thread or calling some function that processes the window's messages.
Basically what I am trying to do is write my own pseudo task bar in C++. The program needs to idle until another program is started up, at which point it needs to visually depict that the other program is running. For each other program that is running, the user should be able to click on the visual representation and have Windows switch focus to the selected program.
The big underlying question at this point: is this even a possibility? Or has Windows hidden most/all of its fiddly-bits to make this close to, if not completely, impossible?
[EDIT:] restructured the question
The obvious starting point would be SetWindowsHookEx(WH_SHELL,...); which will get you notifications when top-level windows are created or destroyed (along with some other related events, like a different window being activated, a window's title changing, etc.)
Think ahead to actually bringing the window to the front, as I once researched myself.
SetForegroundWindow() won't work unless issued from the foreground process - neither SwitchToThisWindow() nor the AttachThreadInput() kludge seemed to always work, but maybe I just wasn't doing it right. Anyway as far as I know there no way to make a window foreground as good as Windows does, please enlighten me if say you discover say an undocumented call which actually Works.
It seems possible to me at least in a basic way:
1. Set up a shell hook as described by Jerry
2. figure the executable file from the module handle to access it's icons using shell services
The Vista-like feature of keeping a 'live' miniature of the screen seems much more challenging.
I'm looking to add an element to my wxWidgets GUI that behaves like a terminal emulator. Not in terms of a shell which executes commands, but just the input-output setup of an application running in a terminal.
Basically, the requirements are:
Streaming input/output: When you enter a character, it is added to an input stream, and when something is piped to the terminal, it prints out immediately.
No editing: Once you type in a character, it's permanently there, since it's probably been consumed by the application running in the terminal.
Some sort of scrolling (even if it just shows a few lines or something).
It would be nice if there is something that already does this, but suggestions on how to implement this with already existing controls such as wxTextCtrl would also be welcome.
I know this is a couple weeks late, but hopefully it's still useful. I've got a project called Chameleon that uses a wxWidgets-based VT100 terminal widget, which was itself based off of a project called taTelnet. The Chameleon source is available from my website (download page here). Not sure if it's exactly what you're looking for, but it might give you some ideas. Feel free to let me know if you have any questions about it.
wxWidgets supports redirecting STDOUT to a wxTextCtrl via wxStreamToTextRedirector. As for input, you could override the OnChar event in a wxTextCtrl-derived class to handle this.