Read selected text from current active window

Question

Hi My application is activated by hot-key and uses the clipboard content as input. So the user is needed to select a text copy it to the clipboard using Ctrl-C and then activate the application using its hot-key (Alt-F6 for example). I wish to reduce the number of operations the user performs and read the selected data by the application. Is it possible to read the current selected data from any (active) window? Thanks.

Nguyen Thien Nhan · Answer

Hi Alan. Your code is magnificent but it does not work with IE. You can edit it plz ? I search on google but not see. Thank you very much

Abbas Khodaeian · Answer

Hi dear Friend I have same problem with the thread handle but i don't know any thing about Win32 and API. I need to paste some data in the other window. For example: My app have a active window and have some reuseable data that i need them every time. when i work with other apps i need to copy some data from my app to the last active window before activing window of my app. when i clicking in some field of my window i need copy the related data into the window that last before activated and foreground of my app. Please help me to create this. i useing the C#.NET Language. Thanks in Advanced. Sincerely Yours Abbas Khodaeian

YelCav · Answer

Thanks Alan it worked perfectly ! :-) I just update the copy command with the window handler from the get focus command.

Alan · Answer

The problem is that GetForegroundWindow() only gets a handle to a top level window. To get a handle to the control with the focus you'll need to go through the rigmarole I did in my earlier post to get focusedHandle and then include that in your call to SendMessage().

YelCav · Answer

I'm trying a simple code to force the active window to copy its selected text to the clipboard: IntPtr activeWindow = GetForegroundWindow(); SendMessage(activeWindow WM_COPY 0 0); This should be sufficient as any application can read from the clipboard the only problem is that its not working .... Any ideas?

YelCav · Answer

Thanks a lot Alan I will try it.

Alan · Answer

It's possible to read the selected text in an edit control (or rich edit control) which currently has the focus in another application using the following code: using System.Runtime.InteropServices; // declarations required for Win32 functions [ DllImport ( user32.dll )] static extern bool ShowWindow( IntPtr hWnd int nCmdShow); [ DllImport ( user32.dll )] static extern IntPtr GetForegroundWindow(); [ DllImport ( user32.dll  SetLastError = true )] static extern uint GetWindowThreadProcessId( IntPtr hWnd out uint lpdwProcessId); [ DllImport ( kernel32.dll )] static extern uint GetCurrentThreadId(); [ DllImport ( user32.dll )] static extern bool AttachThreadInput( uint idAttach uint idAttachTo bool fAttach); [ DllImport ( user32.dll )] static extern IntPtr GetFocus(); [ DllImport ( user32.dll )] static extern int SendMessage( IntPtr hWnd uint Msg int wParam StringBuilder lParam); // second overload of SendMessage [ DllImport ( user32.dll )] static extern int SendMessage( IntPtr hWnd uint Msg out int wParam out int lParam); const uint WM_GETTEXT = 0x0D; const uint WM_GETTEXTLENGTH = 0x0E; const uint EM_GETSEL = 0xB0; // code needed to get selected text - returns empty string if nothing selected IntPtr hWnd = GetForegroundWindow(); uint processId; uint activeThreadId = GetWindowThreadProcessId(hWnd out processId); uint currentThreadId = GetCurrentThreadId(); AttachThreadInput(activeThreadId currentThreadId true ); IntPtr focusedHandle = GetFocus(); AttachThreadInput(activeThreadId currentThreadId false ); int len = SendMessage(focusedHandle WM_GETTEXTLENGTH 0 null ); StringBuilder sb = new StringBuilder (len); int numChars = SendMessage(focusedHandle WM_GETTEXT len + 1 sb); int start next; SendMessage(focusedHandle EM_GETSEL out start out next); string selectedText = sb.ToString().Substring(start next -start); In order for this code to work it needs to be within another process which has a running message loop. The idea is to get a handle to the current active application get the Id of the current thread in that application and then attach it to the current thread in your own application. This then enables us to get a handle to the control which currently has the focus before detaching the threads. It's then easy to get the whole of the text in the control and the limits of the selected text. To avoid the warning you get that the managed method AppDomain.GetCurrentThreadId() is obsolete (actually it isn't!) I've used the corresponding Win32 function instead.