In WPF is it possible to make a Window "Always on top" of another external process window?
Suppose I would want my application to show always over the "notepad.exe" window only?
You're looking for the SetWindowPos function. In C#, you can implement a wrapper as such:
[DllImport("user32.dll")]
static extern bool SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter, int X, int Y, int cx, int cy, uint uFlags);
You can learn more on pinvoke about the supported parameters that you can pass - you will need to reliably identify the window handle for the process, and then overlay the window.
I want to tile two windows programs horizontally in C#. It's for a data view program using Chrome for viewing 2d images and Unity3d is for 3d and navigation.
For example, i can select two programs in windows task manager, and the context has an option to tile them.
Is there a handle in the .Net framework for tiling different program windows?
Probably the best thing is to use MoveWindow (Where hWnd is the window to move):
[DllImport("user32.dll", SetLastError = true)]
internal static extern bool MoveWindow(IntPtr hWnd, int X, int Y, int nWidth, int nHeight, bool bRepaint);
MoveWindow(ApplicationHandle, 600, 600, 600, 600, true);
If you don't know the window pointer, you can use the FindWindow functionality.
Also worth a read is MSDN SetWindowPos (Very similar to MoveWindow).
According to my research, when I run C# executable which opens WinForm, within .NET, they don't offer the function to access those WinForm object from separate c# process (separate file I mean) but win32 API does.
Then I came across 3 functions from API.
FindWindow();
GetWindowLong();
CallWindowProc()
I need to call it from top down to the bottom but then I got stuck by CallWIndowProc() because
I can't figure what I should pass for last 3 arguments.
private static extern UIntPtr CallWindowProc(IntPtr a, IntPtr b, uint c, IntPtr d, IntPtr e);
c, d and e
According to the doc, it should be some sort of "message" which is int. But where can I get such value???
http://msdn.microsoft.com/en-us/library/ms633571(v=vs.85).aspx
Code:
[DllImportAttribute("User32.dll")]
private static extern IntPtr FindWindow(String ClassName, String WindowName);
[DllImportAttribute("User32.dll")]
private static extern long GetWindowLong(IntPtr a, int b);
[DllImportAttribute("User32.dll")]
private static extern UIntPtr CallWindowProc(IntPtr a, IntPtr b, uint c, IntPtr d, IntPtr e);
[STAThread]
static void Main(string[] args)
{
IntPtr lResult;
uint lMsg = 0;
IntPtr HWND = FindWindow("WindowsFormsApplication1.Form1", "Form1");
int GWL_WNDPROC = -4;
long WNDPROC = GetWindowLong(HWND, GWL_WNDPROC);
lResult = CallWindowProc(WNDPROC, HWND, lMsg, 0, 0);
}
Clarification
OK.. I should have made it clear.. my goal is to run following chunk of code against the WebForm being executed. (I'ts WatiN)
var t = new Thread(() =>
{
Settings.AutoStartDialogWatcher = false;
var ie = new IE(form1.webBrowser1.ActiveXInstance);
ie.GoTo("http://www.google.com");
ie.TextField(Find.ByClass("lst")).TypeText("this is awesome!!");
ie.Button(Find.ByName("btnG")).Click();
});
t.SetApartmentState(ApartmentState.STA);
t.Start();
What message you are trying to send to callWinProc?
Arguments are
nProc is a value returned previously by SubClassWindow() (Source Window).
hWnd is the handle to the window that was subclassed (target window).
nMsg is the message (one of the WM_* values defined in WINDOWS.CH, basically kind of event or message like click is one message). For complete system messages see http://msdn.microsoft.com/en-us/library/ms644927(v=vs.85).aspx#system_defined
wParam depends on nMsg. For click, it takes left or right click
lParam depends on nMsg. for click it takes the location as lparam
you can see wparam and lparam defination for each message.
It looks like you're trying to call the window proc of a window from a different thread/process. I'm assuming this because you're using FindWindow, and I can't see where you created the window. If that is what you are doing, CallWindowProc won't work because you cannot call a window proc from a thread other than the one that created the window. What you need is SendMessage, which accepts the same last four parameters (HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam) - to interpret them you need to know what message you're sending.
I recommand to use the parameter names from the native methode just for clearness. You can get those pinvoke signatures from pinvoke.net so you don't have to do it on your own all the time. These messages are definded in header files and documented in the msdn. Its quiete hard to use the right message in the correct manner if you're new to win32 and/or C#.
If you want to intercept the windows messages of your form you need a windows message hook, but this doesn't work in .Net. You can also read this article which cover this topic.
Maybe you should try to find a complete different solution for your problem. Other IPC methodes etc.
EDIT: The CLR type of your form (WindowsFormsApplication1.Form1) is not the class name you have to put in FindWindow, FindWindow is an unmanaged api and isn't aware of the CLR typesystem. Try out Spy++ to investigate some windows on your PC.
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 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();