how to get text from a window with specific HWND? - c++

I'm new to win32 programming and haven't worked around with cpp for a long time. What I intend to do is to get a window's HWND via spy++, and get the text of this window. The problem is that I don't know how to create a HWND object, could anyone give me some idea? Thanks a lot!

If you have the numeric value of the HWND, you can cast it to the right type. Start with an integer of the right size, e.g.:
uintptr_t numeric_hwnd = 0x987654;
HWND hwnd = reinterpret_cast<HWND>(numeric_hwnd);

Related

c++ mfc: update HWND through a control box

Can anyone help me how I update a HWND value through an edit control or any other kind of text box? I tried the following
void ChwndtestDlg::OnBnClickedButton1()
{
TCHAR thebuffer[100];
HWND thetext = (HWND)thebuffer;
GetDlgItemText(IDC_EDITWINDOW, thebuffer, 100);
::SendMessage(thetext,WM_SETTEXT,0,(LPARAM)L"hello");
}
But, that does not work! I'm new to all of this, and I'll be grateful for any help. Please bear in mind that I already know about enumwindows, and I have already successfully changed text in another program from my program, but I want to actually update the HWND in my edit control. It is supposed to work like so...
program 2's current hwnd = 0x00000:
open my program -> open program #2 -> input 0x00000 into textbox in my program -> click button in my program to update the hwnd value -> input text in my programs text editor -> text goes to program 2's text editor. I'm aware that there are other ways of doing this, but I would really like to do it the way I have described. Thanks in advance. I found a similar question, but the answer was to use enumwindows, but I don't want to use that.
You are typecasting the TCHAR[] itself to an HWND. That will never work. You need to extract the TCHAR[] text from the edit control, then use _stscanf() or similar parsing function to convert that text value to an integer which can be typecasted to an HWND, then assign your other text to that HWND as needed.
For example:
void ChwndtestDlg::OnBnClickedButton1()
{
CString sWnd;
if (GetDlgItemText(IDC_HWNDEDIT, sWnd) > 0)
{
HWND hWnd;
if (_stscanf((LPTSTR)sWnd, _T("%p"), &hWnd) == 1)
{
CString sText;
GetDlgItemText(IDC_TEXTEDIT, sText);
::SendMessage(hWnd, WM_SETTEXT, 0, (LPARAM)(LPTSTR)sText);
}
}
}

FindWindow is not working?

I just want to know why this code is not working?
HWND hWnds = FindWindow(NULL,(LPCTSTR)"Calculator");
It always returns NULL for the hWnds....
Any idea how to fix this? Thank you :)
Dont cast the string.
HWND hWnds = FindWindow(NULL,_T("Calculator"));
Make a folder named 'Calculator' and enter into it using Windows Explorer.
Now run your program - wrong window handle would be returned!
Using Spy++ on Windows 7, I found out class-name of Calculator window to be: CalcFrame.
Try using this:
HWND hWnds = FindWindow(_T("CalcFrame"), NULL);

How to get names of the icons on desktop

guys.
I want to obtain names of icons on desktop in c++. And I know how to get their handle:
HWND hwnd = FindWindow("Progman","Program Manager");
HWND hwndSHELLDLL_DefView = ::FindWindowEx( hwnd, NULL, "SHELLDLL_DefView", NULL );
HWND hwndSysListView32 = ::FindWindowEx( hwndSHELLDLL_DefView, NULL, "SysListView32", "FolderView" );
What's next?
First, you need to get the location of the desktop folder using SHGetFolderLocation.. Next, you enumerate the contents of this folder using IShellFolder::EnumObjects
From here, the sky is the limit. Tons of information on interacting with the windows shell here.
Have fun!
Update:
A quick google search turns up this sample which seems to do exactly what you want.

window handle in MFC?

how to get window handle in MFC??
It's the m_hWnd member of your CWnd.
CWnd::GetSafeHwnd is a little "safer" because it can be used with a NULL CWnd pointer
http://msdn.microsoft.com/en-US/library/d64ehwhz%28v=vs.80%29.aspx
Use CWnd::GetSafeHwnd() to get the HWND from a CWnd object; use CWnd::FromHandle to bind a HWND to a temporary CWnd object.
Access the m_hWnd member of your CWnd, like this:
HWND Handle = this->m_hWnd
There are two methodes:
First one, you can use the m_hWnd member variable of your CWnd class to get the window handle.
If you want get the other window's handle, you can use FindWindow windows API. like this:
HANDLE hWind = FindWindow( your_win_class_name, your_win_name );
to use "getsafeHwnd" function, you must c before you use the return value
HANDLE hwnd =FindWindowW( __in_opt LPCWSTR lpClassName,__in_opt LPCWSTR lpWindowName);
first one is class name "Button" or "Edit control"
second one is window name.Handler of the window (m_hWnd).

Reading from a text field in another application's window

Is there a way for a Windows application to access another applications data, more specifically a text input field in the GUI, and grab the text there for processing in our own application?
If it is possible, is there a way to "shield" your application to prevent it?
EDIT: The three first answers seem to be about getting the another applications window title, not a specific text input field in that window.
I'm no Windows API expert, so could you be more exact how do I find a certain text field in that window, what are the prerequisites for it (seems like knowing a window handle something is required, does it require knowing the text field handle as well? How do I get that? etc...)
Code snippets in C++ really would be really appreciated. MSDN help is hard to browse since Win32-API has such horrible naming conventions.
Completed! See my answer below for a how-to in C++.
For reading text content from another application's text box you will need to get that text box control's window handle somehow. Depending on how your application UI is designed (if it has a UI that is) there are a couple of different ways that you can use to get this handle. You might use "FindWindow"/"FindWindowEx" to locate your control or use "WindowFromPoint" if that makes sense. Either way, once you have the handle to the text control you can send a "WM_GETTEXT" message to it to retrieve its contents (assuming it is a standard text box control). Here's a concocted sample (sans error checks):
HWND hwnd = (HWND)0x00310E3A;
char szBuf[2048];
LONG lResult;
lResult = SendMessage( hwnd, WM_GETTEXT, sizeof( szBuf ) / sizeof( szBuf[0] ), (LPARAM)szBuf );
printf( "Copied %d characters. Contents: %s\n", lResult, szBuf );
I used "Spy++" to get the handle to a text box window that happened to be lying around.
As for protecting your own text boxes from being inspected like this, you could always sub-class your text box (see "SetWindowLong" with "GWL_WNDPROC" for the "nIndex" parameter) and do some special processing of the "WM_GETTEXT" message to ensure that only requests from the same process are serviced.
OK, I have somewhat figured this out.
The starting point is now knowing the window handle exactly, we only know partial window title, so first thing to do is find that main window:
...
EnumWindows((WNDENUMPROC)on_enumwindow_cb, 0);
...
which enumerates through all the windows on desktop. It makes a callback with each of these window handles:
BOOL CALLBACK on_enumwindow_cb(HWND hwndWindow, LPARAM lParam) {
TCHAR wsTitle[2048];
LRESULT result;
result = SendMessage(hwndWindow, WM_GETTEXT, (WPARAM) 2048, (LPARAM) wsTitle);
...
and by using the wsTitle and little regex magic, we can find the window we want.
By using the before mentioned Spy++ I could figure out the text edit field class name and use it to find wanted field in the hwndWindow:
hwndEdit = FindWindowEx(hwndWindow, NULL, L"RichEdit20W", NULL);
and then we can read the text from that field:
result = SendMessage(hwndEdit, WM_GETTEXT, (WPARAM) 4096, (LPARAM) wsText);
I hope this helps anyone fighting with the same problem!
Look at AutoHotkey. If you need an API for your application, look at their sources.
To prevent it, use a custom widget instead of WinForms, MFC or Win32 API. That is not foolproof, but helps.
Yes it is possible in many ways (one way is to use WINAPI GetWindow and GetWindowText).
First, get a handle to the textbox you want to retrieve text from (using FindWindow, EnumChildWindows and other APIs), then:
Old VB6-codeexample, declaration of API:
Private Declare Function GetWindowText Lib "user32" Alias "GetWindowTextA" (ByVal hwnd As Long, ByVal lpString As String, ByVal cch As Long) As Long
Private Declare Function GetWindowTextLength Lib "user32" Alias "GetWindowTextLengthA" (ByVal hwnd As Long) As Long
Code to extract text:
Dim MyStr As String
MyStr = String(GetWindowTextLength(TextBoxHandle) + 1, Chr$(0))
GetWindowText TextBoxHandle, MyStr, Len(MyStr)
MsgBox MyStr
About how to shield the application to prevent it, you could do many things.
One way would be to have a own control to handle text input that build up the text from lets say a couple of labels placed where the text would be, or that draws the text graphically.
You can also get text from a richedit control with EM_GETTEXTRANGE message, but it works only in the same process in which the control was created.