Sending keystrokes to other *non-focus* application

In order to send keystorkes or mouse clicks to other application that is not in focus, I found
in the internet the concept of using SendInput while attaching my application thread to the application I want to control. Here is the short console program code for writing the letter 'g' on the notepad program.
But still problem - it doesn't put the letter on the notepad... why?

Code:

#include "stdafx.h" #include "conio.h" #include "windows.h" void sendKey(WORD wVk) { INPUT input[2]; input[0].ki.wVk = wVk; input[0].ki.wScan = 0; input[0].ki.dwFlags = 0; //press down; input[0].ki.time = 0; input[0].ki.dwExtraInfo = 0; input[0].type = INPUT_KEYBOARD; input[1].ki.wVk = wVk; input[1].ki.wScan = 0; input[1].ki.dwFlags = KEYEVENTF_KEYUP; input[1].ki.time = 0; input[1].ki.dwExtraInfo = 0; input[1].type = INPUT_KEYBOARD; SendInput(2, input, sizeof(INPUT)); } int _tmain(int argc, _TCHAR* argv[]) { TCHAR sText[1024]; HWND hTargetWnd; DWORD processID; DWORD threadID; HWND hNotepadWnd = FindWindow(NULL, L"Untitled - Notepad"); hTargetWnd=FindWindowEx(hNotepadWnd,NULL,L"Edit",NULL); threadID = GetWindowThreadProcessId(hTargetWnd , &processID); if(hTargetWnd) { wsprintf(sText, L"Target window found\nWindow = %p\nprocessID = %x\nThreadID = %x\n",hTargetWnd,processID,threadID); wprintf(L"%s",sText); if(AttachThreadInput( GetCurrentThreadId(), threadID,true)) { sendKey('G'); AttachThreadInput(GetCurrentThreadId(),threadID, false); } } else { wprintf(L"Window Notepad wasn't found\n"); } // if there was SendInput, it also should be seen here while(_kbhit()) { wprintf(L"%c",getch()); } // wait for keystroke to exit while(!_kbhit()); return 0; }

If you have the handle to the NotePad application then try posting a WM_CHAR message, for example:

Code:

PostMessage( hTargetWnd, WM_CHAR, 'g', 0 );

Thanks, that may work.

I tried to work with PostMessage and the messages are indeed, received by the notepad.
But I found that in this case, I must know what the target program is designed to receive.
I tried for example to send WM_LBUTTONDOWN in order to simulate left mouse button click, but the target program didn't react to this even it received it.
When I checked, using Spy++ the messages it accepts when the mouse is really on it, I found the messages are much more complicated than just WM_LBUTTONDOWN and includes WM_NCHITTEST, WM_SETCURSOR and more. Why it is not just WM_LBUTTONDOWN ? I don't know. it's first time for me in this subject.

If you can give some description on this behavior and a solution, that will be great.
Thanks

Quote:

Originally Posted by Scarlet7

If you have the handle to the NotePad application then try posting a WM_CHAR message, for example:

Code:

PostMessage( hTargetWnd, WM_CHAR, 'g', 0 );

If I want to send "Alt+B", for example?

Quote:

Originally Posted by audi02

Thanks, that may work.

I tried to work with PostMessage and the messages are indeed, received by the notepad.
But I found that in this case, I must know what the target program is designed to receive.
I tried for example to send WM_LBUTTONDOWN in order to simulate left mouse button click, but the target program didn't react to this even it received it.
When I checked, using Spy++ the messages it accepts when the mouse is really on it, I found the messages are much more complicated than just WM_LBUTTONDOWN and includes WM_NCHITTEST, WM_SETCURSOR and more. Why it is not just WM_LBUTTONDOWN ? I don't know. it's first time for me in this subject.

If you can give some description on this behavior and a solution, that will be great.
Thanks

I think that WM_SETCURSOR and similar are always given to your program, even if you don't catch them. I would expect Notepad to listen for that so that it knows where you're clicking (to move the cursor to that spot, on a button, etc.)

Quote:

I tried for example to send WM_LBUTTONDOWN in order to simulate left mouse button click, but the target program didn't react to this even it received it.

What reaction were you expecting, or hoping for on a left mouse button?

If to bring the NotePad to the top window the use the following:

Code:

SetForegroundWindow( hTargetWnd );

If to set the cursor position then WM_LBUTTONDOWN will work, but only the x y coordinates within the text region, the following will set the cursor coords to x=0 y=0 (top left of window):

Code:

PostMessage(hTargetWnd, WM_LBUTTONDOWN, MK_LBUTTON, MAKELPARAM(0,0)); PostMessage(hTargetWnd, WM_LBUTTONUP, MK_LBUTTON, MAKELPARAM(0,0));

The following code example will bring the NotePad to the front and write 3 lines the insert some text into line 1:

Code:

void SendString(HWND h, char *text) { int len = strlen(text); for(int i = 0; i < len; i++) PostMessage(h, WM_CHAR, text[i], 0); } void SetCursor(HWND h, short x, short y ) { PostMessage(h, WM_LBUTTONDOWN, MK_LBUTTON, MAKELPARAM(x,y)); PostMessage(h, WM_LBUTTONUP, MK_LBUTTON, MAKELPARAM(x,y)); } int _tmain(int argc, _TCHAR* argv[]) { ... SetForegroundWindow(hTargetWnd); SetCursor(hTargetWnd, 0,0); SendString(hTargetWnd, "Hello World line 1\n"); SendString(hTargetWnd, "Hello World line 2\n"); SendString(hTargetWnd, "Hello World line 3\n"); SetCursor(hTargetWnd, 20,0); SendString(hTargetWnd, "(Inserted)"); ... }

Thanks Scarlet7.

1) It works.
2) I don't want to make the target program (NotePad in this example) focused , so we can use the PostMessage without SetForegroundWindow(hTargetWnd) and SetCursor(hTargetWnd, 0,0)
3) I found that the reasone I didn't have the corrrect response to WM_LBUTTONDOWN etc' was because I didn't use the correct child window - my mistake!