I am trying to inject sendkeys into the active desktop application, however am finding that I loose the active desktop application focus to the application I'm building. And thus application is a fail.
The application I'm building should never gain focus over the active window when run via the keypress.
EG.
Keypress mapped to run app I'm building, eg app.exe "key 1"
App then injects send keys for typing out "key 1" to the active application or uses windows copy, sets buffer to "key 1" and then sends CTRL+V to the active application in focus.
I've tried creating a console app but gains focus of itself.
Then I tried a windows service however I then realised I needed to build another app to send the command to the service which will again gain focus.
Suggestions?
Some code I used for getting active process: Always gets itself as it becoms the active app, so quite pointless.
````
class Program
{
[DllImport("user32.dll")]
static extern IntPtr GetForegroundWindow();
//[DllImport("user32.dll")]
//static extern bool SetForegroundWindow(IntPtr hWnd);
static void Main(string[] args)
{
IntPtr handle = GetForegroundWindow();
Process p = Process.GetCurrentProcess();
Debug.Print("p.ProcessName = " + p.ProcessName);
String msg = "";
msg += "p.ProcessName = " + p.ProcessName.ToString() + "\n";
}
````
Spoooooky, I 'solved' this one today while spending a free hour adding some remote monitoring to a factory terminal.
Make a regular winforms project, set the forms WindowState to minimized and ShowInTaskbar to false. Then on the form.load event call hide()
Now you have an invisible program that can't be manually targetted, now you just need to make sure it's targetting the window you want.
Which is done like this in VB (you're a big boy, translate it online by yourself):
'in the form class def
Declare Auto Function FindWindow Lib "User32.dll" (ByVal lpClassName As String,ByVal lpWindowName As String) As IntPtr
Declare Auto Funtion SetForeGroundWindow Lib "User32.dll"(ByVal Hwnd As IntPtr) As Long
Sub blah()
Dim Handle as IntPtr = FindWindow(Nothing,"ClockWatcher")
SetForeGroundWindow(Handle)
End Sub
Which is when I would use windows.forms.sendkeys(thething) to simulate the keypresses. Good thing is, focus remains on the clockwatch program, and nothing the user can do will get focus onto your form. Unless you make a taskbar icon, they have to use taskmgr to stop the program :P
I wanna send key stroke to a program even if it is running in background. But I can do this only for NOTEPAD like this,
[DllImport("user32.dll")]
protected static extern byte VkKeyScan(char ch);
[DllImport("user32.dll", SetLastError = true)]
protected static extern IntPtr FindWindowEx(IntPtr hwndParent, IntPtr hwndChildAfter, string lpszClass, string lpszWindow);
[DllImport("User32.Dll", EntryPoint = "PostMessageA")]
protected static extern bool PostMessage(IntPtr hWnd, uint msg, int wParam, int lParam);
char Key = // key value to send
IntPtr hWnd = FindWindowEx(_handle, IntPtr.Zero, "edit", null); // _handle is the windows handle of the program (here its notepad)
PostMessage(hWnd, WM_KEYDOWN, VkKeyScan(Key), 0);
But for all other applications I can't send keystrokes if its in background. Since I don't know the lpszClass of that program (I think this is the userControl name of the typing area in that program. For NotePad it is "edit". I found this surfing internet).
For all other applications what I'm doing is, get the application to foreground, then send the key, then again get my program foreground. I need my program to be run as foreground always.
[DllImport("USER32.DLL")]
public static extern bool SetForegroundWindow(IntPtr hWnd);
SetForegroundWindow(_handle); // _handle is the windows handle of the program
System.Threading.Thread.Sleep(50); // Waiting few milliseconds till application coming to foreground.
wsh.SendKeys(Key.ToString(), ref wait); // wsh is WshShellClass wsh= new WshShellClass();
SetForegroundWindow(_mainHandle); // _mainHandle is the windows handle of my application
But this way is not working. some keys getting missed and the program foreground->background->foregound->background...... like its dancing...
How to send keys to other applications if its running in background.
or are there any way/source to find the lpszClass of a program ?
Sorry if I have missed any required information. this is a large application. I have posted only required parts here. If someone needs any additional information, pls ask.
I think you'll need to have the background program install a low-level keyboard hook via the win32 function SetWindowsHookEx().
Here's the MSDN documentation for SetWindowsHookEX()
http://msdn.microsoft.com/en-us/library/ms644990(v=vs.85).aspx
And here's the KB article on how to do it from C#
http://support.microsoft.com/kb/318804
This article goes into some detail, too: http://www.codeguru.com/columns/vb/article.php/c4829
I expect your app will get caught by various spyware/anti-virus software as a keyboard logger, though.
Good luck.
You may be able to figure out the lpszClass of the program using an inspection tool such as WinSpy++. It gives you a crosshair that you can drag and position over the desired control. This was able to easily provide me with the "edit" class name for notepad.
If things aren't working, click the "More>>" button in the lower right of WinSpy++, then click the "Locate" button to view the control hierarchy; you may need to post the WM_KEYDOWN message to one of the parent or child controls instead.
I'm trying to get my C# form to be parented correctly in a third party app, I have the handle to the control that I would like my form parented to but just can't seem to get it to work.
alt text http://img693.imageshack.us/img693/8871/examplec.jpg
I would like to create my form so that it is part of the MDIClient, handle 005E0ED6. Just like Window 01D7157D.
Is this possible? If so can it be done in C#?
How have you tried doing it? Did you try SetParent? See the following StackOverflow question to see if it helps. Embedding HWND into external process using SetParent
This code seems to work:
[DllImport("user32.dll")]
private static extern
IntPtr GetWindowThreadProcessId(IntPtr hWnd, IntPtr ProcessId);
[DllImport("user32.dll")]
private static extern
IntPtr AttachThreadInput(IntPtr idAttach, IntPtr idAttachTo, int fAttach);
WinAPI.SetParent(this.Handle, otherappshandle);
IntPtr otherprocessID = GetWindowThreadProcessId(otherappshandle, new IntPtr(0));
IntPtr threadID = new IntPtr(AppDomain.GetCurrentThreadId());
AttachThreadInput(threadID , otherprocessID , 1);
Good luck. I've gone down that road, and found that there's enough little irritating gotchas that I eventually gave up on it.
SetParent() and the like will get you part of the way there, but there's a bunch of little gotchas to watch as far as the overall system (message pump blocking etc.) that just make it a time sink.
With WinForms, especially, I'd highly recommend just running your UI in the main process (if you can), and if you want to isolate your processing in another process do that instead.
I want to send a pressKey event to a certain application which is not the active application IN Windows so I have to use the sendMessage/postMessage api calls.
However, I need to know the exact child window that is active IN the application and send the pressKey message to it...
I was using GetTopWindow and GetWindow(GW_CHILD) api calls to get the top child window of the main window, and do it again with the obtained child window to get the top grandchildWindow, and keep doing it until I found a childwindow with no more childwindows. This works great for some applications but in some cases it doesn't. Sometimes the parent window is the active window, not one of its childwindows, so getting the parent's top child window will not work cause I will be sending a message to the wrong window.
The only way I found of doing this (getting the handler of the actual active window) was using the GuiThreadInfo api call but it only works if the target application is the active one IN Windows. As I mentioned in the beginning, it isn't so the handler comes null.
I can bring the application to the top using setForegroundWindow api call but I DON'T want to do this. I also tried the AttachThreadInput and GetFocus api calls, but again, they only work if the target application is the active application IN windows.
Any ideas? Thanks
I assume from the things that you have tried that you know how to get a handle to your main window, but if you don't just leave a comment and I will post a snippet for that.
I combined a few things that I found on the net to figure this out, but the main one is this one. I don't have a great app to test this with, but it works in a simple case. One exception is that I think if you use tool windows in your application it will not find that as it is coded because I think the GetLastActivePopup method doesn't include them (not sure about that, and didn't test that case).
[DllImport("user32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool IsWindowVisible(IntPtr hWnd);
[DllImport("user32.dll")]
static extern IntPtr GetLastActivePopup(IntPtr hWnd);
[DllImport("user32.dll", ExactSpelling = true)]
static extern IntPtr GetAncestor(IntPtr hwnd, uint gaFlags);
const uint GA_PARENT = 1;
const uint GA_ROOT = 2;
const uint GA_ROOTOWNER = 3;
public static IntPtr GetAppActiveWindow(IntPtr hwnd)
{
IntPtr activeAppWindow = IntPtr.Zero;
if (hwnd != IntPtr.Zero)
{
//Get the root owner window (make sure we are at the app window
//if you already have a handle to the main window shouldn't have
//to do this but I put it in just in case
hwnd = GetAncestor(hwnd, GA_ROOTOWNER);
while ((activeAppWindow =
GetLastActivePopup(hwnd)) != activeAppWindow)
{
if (IsWindowVisible(activeAppWindow))
break;
hwnd = activeAppWindow;
}
}
return activeAppWindow;
}
If you know the Window title and the Window class name, take a look at FindWindow() and FindWindowEx() and see if those meet your needs.
FindWindow(): http://msdn.microsoft.com/en-us/library/ms633499.aspx
FindWindowEx(): http://msdn.microsoft.com/en-us/library/ms633500(VS.85).aspx
I have a requirement that an application I am working on prevent the user from being able to easily capture the contents of the screen.
I have communicated that there is no feasible way to completely prevent this from happening, but I'm looking for methods to introduce some hurdles to the process.
I'm using C#/.NET 2.0 and WinForms
You can't.
The best you can do is render to a hardware accelerated device on an overlay, similar to what video players used to do. Basically, you paint your entire window blue, and render your graphics onto the video card, and internally the video card will replace the blue with the graphics. The downside to this is you have to give up using winforms controls, and I don't know of any way to do this with .NET easily. I think if you use DirectShow.NET, one of their samples is putting your own graphics into a stream.
Even after doing all of that, it's still possible to get a screenshot. Just take a picture of the screen with a digital camera.
From here:
A. Windows implements Print Screen using a registered hotkey. Windows
uses the predefined hotkeys IDHOT_SNAPDESKTOP and IDHOT_SNAPWINDOW to
handle Print Screen. These correspond to Print Screen, which captures
the entire screen, and Alt+Print Screen, which captures only the
active window. To disable these functions all you have to do is
register the hotkeys, which causes Windows to send your app a
WM_HOTKEY message when the user presses either hotkey. Your
implementation can ignore the message to bypass the default
screen-capture behavior. A good place to do it is in your mainframe
class.
FWIW, it is possible. Here's some code:
This would be a dll that you create, then call the HookKeyboard method from your application. I've tested it and it works. Granted, if someone takes a picture with a camera it can't help, but, point made. NYAH!
namespace KeyboardHook
{
public class Hooker
{
[StructLayout(LayoutKind.Sequential)]
public struct KBDLLHOOKSTRUCT
{
public int vkCode;
public int scanCode;
public int flags;
public int time
;
public int extraInfo;
}
public delegate int HookProc(int nCode, int wParam, IntPtr ptrKBDLLHOOKSTRUCT);
[DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall, SetLastError = true)]
public static extern IntPtr SetWindowsHookEx(int idHook, HookProc callBack, IntPtr hMod, int threadId);
[DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall, SetLastError = true)]
public static extern int CallNextHookEx(IntPtr hhk, int nCode, int wParam, IntPtr lParam);
private static IntPtr kbh_Handle;
private static HookProc kbh_HookProc;
private const int VK_SNAPSHOT = 0x2C;
private const int WM_KEYDOWN = 0x0100;
private const int WM_SYSKEYDOWN = 0x0104;
private const int WH_KEYBOARD_LL = 13;
private static int LowLevelKeyboardProc(int nCode, int wParam, IntPtr lParam)
{
if (nCode < 0)
{
CallNextHookEx(kbh_Handle, nCode, wParam, lParam);
return 0;
}
if (wParam == WM_KEYDOWN)
{
IntPtr kbdll = lParam;
KBDLLHOOKSTRUCT kbdllstruct = (KBDLLHOOKSTRUCT)Marshal.PtrToStructure(kbdll, typeof(KBDLLHOOKSTRUCT));
if (kbdllstruct.vkCode == VK_SNAPSHOT)
return -1;
}
return CallNextHookEx(kbh_Handle, nCode, wParam, lParam);
}
public static void HookKeyboard()
{
try
{
kbh_HookProc = LowLevelKeyboardProc;
kbh_Handle = SetWindowsHookEx(WH_KEYBOARD_LL, kbh_HookProc, Marshal.GetHINSTANCE(Assembly.GetExecutingAssembly().GetModules()[0]), 0);
if (kbh_Handle != IntPtr.Zero)
System.Diagnostics.Debug.WriteLine(String.Format("It worked! HookHandle: {0}", kbh_Handle));
else
{
throw new Win32Exception(Marshal.GetLastWin32Error());
}
}
catch (Exception ex)
{
System.Diagnostics.Debug.WriteLine(String.Format("ERROR: {0}", ex.Message));
}
}
}
}
You can try using IpcProtectWindow provided in msipc.dll.
[DllImport("msipc.dll", SetLastError = false, CharSet = CharSet.Unicode, CallingConvention = CallingConvention.StdCall)]
internal static extern int IpcProtectWindow([In] IntPtr hwnd);
Download the SDK from Microsoft
Call the function above and provide the handle of the form you would like to protect. (Form.Handle property)
You'll have two cases here that you need to worry about. One, when your window/application has focus, the other when it doesn't have focus.
When it doesn't have focus, there's not a whole lot you can do, i.e. if the user clicks off of your app and onto the desktop, keys aren't sent to your app so you'll never see them. In that case, you can minimize to the tray when your app loses focus (or, perhaps, place a "blank" panel over the form to prevent users from seeing anything on it which will also prevent a print-screen from being useful).
In the other case, when you have focus, capture keystrokes and examine them. If the Alt key is down and the PrintScreen key is down, reset the value so that a print-screen doesn't occur. (Come to think of it, that may not work. I'd need to test it to be sure.)
You could look into what movie players do. I believe they render directly to a hardware surface (via DirectX). I suspect that you'd need to do this.
This doesn't really answer the questions, but keep in mind that there exists tools to capture screen, and that a simple camera breaks everything.
I mean ok you "have to", but I would (but I'm young and still student, so I don't know much about what can be said) answer that this is just stupid.
Check out the new tech - sivizion.com, they prevent print screen all together - no way to bypass it. If anyone will figure out a way how to hack it, please post here, I couldn't. I think they also license their tech, not sure, check it out.
Well, you could try capturing the button, but I'm not sure how well that will work.
One thing that always annoyed me was that whenever I played a movie, it would never take screenshots of it. If you can render through a separate context, it would make it really annoying to take a picture of it. Perhaps you can send your screen output through something like that?
There are applications that can capture the screen from OpenGL and DirectX apps ! (depending (they are used for recording game movies)
ps. windows aero is DirectX
http://www.fraps.com/
i think thats the application
You can make any casual Print Screen useless using Visual Cryptography and taking advantage of retinal persistence (see this article for details, and bit.ly/vcrypto for a web demo).
The idea is to alternate at high frequency between two or more random noise images, that will combine through persistence of vision to reveal the content. A screen capture will only grab one image, with meaningless random noise.
This comes at the cost of flickering and inducing user headaches, can be defeated by a camera taking a picture of the screen, or by a less casual user that knows photoshop, but will defeat any kind of casual screen capture or frame grabbing.
Might occasionally be useful, in an academic meaning of the term!
It is too late but there is a quick work around,
Simply use it in MDI form
Set TopMost Property of form True, then write below event
private void frmMDI_Deactivate(object sender, EventArgs e){Clipboard.Clear();}
after taking print screen user have to minimize the application, the moment user minimize the app, we are clearing clipboard.
you can use this in logout function or when screen move or resize or any other form event as required :)
Snipping tool also can't copy screens by this if TopMost Property is true.
Yes we can't stop user from capturing screen from external device like phone or cam.
In windows form application, Use this code in form keyup event,
if (e.KeyCode == Keys.PrintScreen)
{
Clipboard.Clear();
}
Form keypreview should be TRUE
Microsoft has been developed an API named SetWindowDisplayAffinity to support the window content protection. This feature enables applications to protect application content from being captured or copied through a specific set of public operating system features and APIs
SetWindowDisplayAffinity(hWnd, WDA_MONITOR);
I solved it using a Timer object and Clipboard.Clear() method.
First add a Timer to your main form with Interval=1 (Very fast), then add the following code in its event:
Clipboard.Clear();