i am having issues with making an injectable notepad text viewer. I think I may have accessed the hwndEdit HWND wrongly. Currently when i run the program it shows
╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠
as the text
#include <stdio.h>
#include <iostream>
#include <string>
#include <Windows.h>
int main() {
AllocConsole();
SetConsoleTitleA("Notepad Viewer");
FILE *c;
freopen_s(&c, "CONOUT$", "w", stdout);
freopen_s(&c, "CONIN$", "r", stdin);
DWORD hwndEditAddress = 0x41E1B4;
HWND hwndEdit = *(HWND*)&hwndEditAddress;
for (;;) {
TCHAR text[256];
SendMessage(hwndEdit, WM_GETTEXT, sizeof(text) / sizeof(text[0]), LPARAM(text));
std::cout << "Current Text: " << text;
std::string input;
std::getline(std::cin, input);
}
}
╠ corresponds to the (extended) ASCII code 204, which is 0xCC in hex. A sequence of 0xCC bytes is used by the Visual C++ CRT to mark uninitialized memory. So, your output is basically a dump of some uninitialized memory region.
In your code, you call SendMessge passing the hwndEdit handle; but the logic you used to initialize this handle is unclear and smells of bug:
DWORD hwndEditAddress = 0x41E1B4;
HWND hwndEdit = *(HWND*)&hwndEditAddress;
This code is strange
DWORD hwndEditAddress = 0x41E1B4;
HWND hwndEdit = *(HWND*)&hwndEditAddress;
You may as well write
HWND hwndEdit = (HWND)0x41E1B4;
Which has the exact same effect.
What happens next is that this value is not the value of a window handle. Therefore the attempt to read the text fails, and text is never modified. Finally, you print an uninitialized character array, which is undefined behaviour.
You need to revisit your logic that obtains the window handle.
Related
There are many similar questions, but mine is a bit different. Mine involves a Windows GUI. I am using an open file dialog or an "OPENFILENAME". I want to get the dialog result as OK when the user clicks the OK button and then open a text encoded file. I have done it in Java, but the UI looks weird. So I am not sure whether or not people would like it. I want to learn C++ as well, so I need some help. I have a text box called "hWndEdit" in the WM_COMMAND message inside my program. After opening, the text in the file is supposed to be displayed in the textBox I have specified. I have defined the function in a header file with the following code:
#include <iostream>
#include <fstream>
#include <windows.h>
using namespace std;
void OpenFile()
{
OPENFILENAME ofn; // common dialog box structure
HWND hwnd = nullptr; // owner window
HANDLE hf; // file handle
// Initialize OPENFILENAME
ZeroMemory(&ofn, sizeof(ofn));
ofn.lStructSize = sizeof(ofn);
ofn.hwndOwner = hwnd;
// Set lpstrFile[0] to '\0' so that GetOpenFileName does not
// use the contents of szFile to initialize itself.
ofn.nMaxFile = sizeof(szFile);
ofn.lpstrFilter = L"NoteRecorder Notes\0(*.recnote)\0Text\0(*.txt)\0";
ofn.nFilterIndex = 1;
ofn.lpstrFileTitle = NULL;
ofn.nMaxFileTitle = 0;
ofn.lpstrInitialDir = NULL;
ofn.Flags = OFN_PATHMUSTEXIST | OFN_FILEMUSTEXIST;
// Display the Open dialog box.
if (GetOpenFileName(&ofn) == TRUE)
{
hf = CreateFile(ofn.lpstrFile,
GENERIC_READ,
0,
(LPSECURITY_ATTRIBUTES)NULL,
OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL,
(HANDLE)NULL);
}
}
Then I call it from my WM_COMMAND message:
case WM_COMMAND:
switch (wParam)
{
case 12:
OpenFile();
break;
}
But when the user presses the OK button in the OPENFILENAME, it doesn't read any text from the file. How can I accomplish this?
And I want to write files with a save file dialog. Tell me how to do that as well.
The main purpose of the functions GetOpenFileName and GetSaveFileName is to provide you with the filename that the user selected. However, doing the actual File Input and Output is a different issue. You can use the standard C/C++ library for that or you can use the Windows API functions, such as CreateFile, ReadFile and WriteFile.
Since you seem to already be using the function CreateFile, it would make sense to call ReadFile after verifying that the function call to CreateFile succeeded (i.e. that it did not return INVALID_HANDLE_VALUE). After reading the data, you can add a terminating null character to the data (you should make sure that the memory buffer is large enough) and then pass it to the SetDlgItemText function (if the text box is in a dialog box) or SetWindowText function.
Is there a standard message that can be sent to a text editor window or a certain WinApi call, that will retrieve the contents of the currently edited text?
For example, to retrieve the current contents of a Notepad window. (assumed that the most up to date text wasn't yet written to a file)
I've tried retrieving the text via SendMessage using WM_GETTEXT, WM_GETTEXTLENGTH but I was able to retrieve the title text only.
In general no there is no standard message for this.
But Windows' Notepad has an "Edit" child which responds to WM_GETTEXT and WM_GETTEXTLENGTH - messages normally used to retrieve text from input controls.
Here's a PoC demonstrating the idea:
#include <iostream>
#include <vector>
#include <string.h>
#include <Windows.h>
BOOL CALLBACK enumProc(HWND hwnd, LPARAM) {
std::vector<char> buf(100);
GetClassNameA(hwnd, buf.data(), 100);
if (strcmp(buf.data(), "Notepad")) return TRUE;
hwnd = FindWindowEx(hwnd, NULL, "Edit", NULL);
if (!hwnd) return TRUE;
int textLength = SendMessageA(hwnd, WM_GETTEXTLENGTH, 0, 0) + 1;
if (textLength <= 0) return TRUE;
buf.resize(textLength);
SendMessage(hwnd, WM_GETTEXT, textLength, (LPARAM)buf.data());
std::cout << buf.data() << "\n";
return TRUE;
}
int main() {
EnumWindows(&enumProc, 0);
}
Works on Windows 10:
I was wondering if it were possible to take text input from a text box (CreateWindowEx "EDIT") and store it as a string or even better a vector
I need to have a textbox that the user can enter or paste text and when I click a button it will alphabetize the words and count unique words etc...
so far I have it reading it in as characters (i dont know how to make it a string) and alphabetizes the characters
so if I type in: how now brown cow
it will output: bchnnoooorwwww
instead of: brown cow how now
my code under the WM_COMMAND case is
int length;
length = GetWindowTextLength(textbox) + 1;
vector<wchar_t> list(length);
GetWindowText(textbox, &list[0], length);
wstring stxt = &list[0];
wstring str(stxt);
sort(str.begin(), str.end());
SetWindowText(sortedOutput, &str[0]);
This answer may be of use to you in devising a solution. I don't really know of one that is not hacky, but it can be done casting of the constness of c_string() from std::string.
https://stackoverflow.com/a/1986974/128581
A std::string's allocation is not guaranteed to be contiguous under the C++98/03 standard, but C++11 forces it to be. In practice, neither I nor Herb Sutter know of an implementation that does not use contiguous storage.
Notice that the &s[0] thing is always guaranteed to work by the C++11 standard, even in the 0-length string case. It would not be guaranteed if you did str.begin() or &*str.begin(), but for &s[0] the standard defines operator[] as:
Returns: *(begin() + pos) if pos < size(), otherwise a reference to an object of type T with value charT(); the referenced value shall not be modified
Continuing on, data() is defined as:
Returns: A pointer p such that p + i == &operator for each i in [0,size()].
(notice the square brackets at both ends of the range)
Thus it follows you can do something like this:
int len = GetWindowTextLength(hwnd) + 1;
std::string s;
s.reserve(len);
GetWindowText(hwnd, const_cast<char*>(s.c_str()), len - 1);
Which is pretty ugly. Welcome any more "correct" answers, though.
Regarding when unicode is enabled on your build, you have to use a wstring or equivalent. Testing that out just a moment ago, this works:
std::wstring title;
title.reserve(GetWindowTextLength(m_window_handle) + 1);
GetWindowText(m_window_handle, const_cast<WCHAR *>(title.c_str()), title.capacity());
In general, regarding the windows api its useful to google their all caps typedefs and figure out what they really are.
Regarding splitting strings, std::string isn't particular good at this kind of manipulation. This is where std::stringstream (or wstringstream for unicode) comes in handy. I am fairly certain stringstream is not guaranteed to be contiguous in memory, so you can't really go around writing directly into its buffer.
// Initialize a stringstream so we can extract input using >> operator
std::wstringstream ss;
ss.str(title);
// Make a vector, so we can store our words as we're extracting them
// and so we can use sort later, which works on many stl containers
std::vector<std::wstring> words;
std::wstring word;
// This will evaluate to false and thus end the loop when its done
// reading the string word by word
while(ss >> word)
{
words.push_back(word);
}
Then proceed with your sorting, but on the new vector words.
Your problem is not a winapi problem. While not the only way, you found a solution to transfer a string back and forth to your edit box.
How to turn that string into a list/vector of strings, with words being the elements of that list/vector is in fact an STL problem.
Basically, you are looking for the C++ equivalent of the C# function String.Split().
And there is already a good question and answer for that, here:
Most elegant way to split a string?
So, all you have to do is a sort of round trip:
Get string from TextBox
Convert string to a std::vector<string>, using your split function (see the other question for how to do that).
Sort the vector in the usual way.
Convert the vector back to a string, which is the inverse of your split function (Hint: std::ostringstream).
Set the resulting string as the text of your TextBox.
Depending on your preferences regarding multi character strings and globalization, you might decide to stick to the ASCII versions at first. On windows, you can compile to MBCS or ASCII. The respective string types are then respectively (TCHAR and LPCTSTR or WCHAR and LPCWSTR or CHAR and LPCSTR). All win32 functions come in two flavors, distinguished by a trailing A or W at the end of the function name, respectively.
AFAIK, while there is std::string and std::wstring, there is no standard implementation for std::basic_string<TCHAR>, which would work along with your compile options.
As for the window handling, here some code example (snippets):
In InitInstance(), I created the dialog (IDD_FORMVIEW) with my input edit box, my button and my static output area as a child window of the main application window:
//
// FUNCTION: InitInstance(HINSTANCE, int)
//
// PURPOSE: Saves instance handle and creates main window
//
// COMMENTS:
//
// In this function, we save the instance handle in a global variable and
// create and display the main program window.
//
BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
hInst = hInstance; // Store instance handle in our global variable
HWND hWnd = CreateWindowW(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, nullptr, nullptr, hInstance, nullptr);
HWND hWndChild = CreateDialogW(hInstance, MAKEINTRESOURCE(IDD_FORMVIEW), hWnd, dlgProc);
if (NULL == hWndChild)
{
DWORD lastError = GetLastError();
wchar_t msg[100];
swprintf_s(msg, _countof(msg), L"error code: 0x%0X\n", lastError);
OutputDebugString(msg);
}
if (!hWnd)
{
return FALSE;
}
ShowWindow(hWnd, nCmdShow);
ShowWindow(hWndChild, SW_SHOW);
UpdateWindow(hWnd);
return TRUE;
}
CreateDialogW() takes as the last parameter a pointer to the dialog handler function, which is called dlgProc() in this example.
This is how that dlgProc() function looks like:
// Message handler for our menu which is a child window of the main window, here.
static INT_PTR CALLBACK dlgProc(
_In_ HWND hwndDlg,
_In_ UINT uMsg,
_In_ WPARAM wParam,
_In_ LPARAM lParam
)
{
BOOL processed = false;
switch (uMsg)
{
case WM_INITDIALOG:
break;
case WM_NOTIFY:
break;
case WM_COMMAND:
{
auto sourceId = LOWORD(wParam);
auto code = HIWORD(wParam);
if (IDC_BUTTON1 == sourceId)
{
if (BN_CLICKED == code)
{
wchar_t text[1024];
GetDlgItemText(hwndDlg, IDC_EDIT1, text, _countof(text));
// TODO: do your string processing here (string -> string)
SetDlgItemText(hwndDlg, IDC_STATIC, text);
processed = TRUE;
}
}
}
break;
default:
break;
}
return processed;
}
I have just mixed a few lines of code to convert wchar_t to wstring to std::string. Here you go!
string GetWindowStringText(HWND hwnd)
{
int len = GetWindowTextLength(hwnd) + 1;
vector<wchar_t> buf(len);
GetWindowText(hwnd, &buf[0], len);
wstring wide = &buf[0];
string s(wide.begin(), wide.end());
return s;
}
This has a vector so you'll need to include it.
I'm trying to output text from Notepad window to console and it's always 0.
What I'm doing wrong?
int main()
{
HWND hwnd = (HWND)0x0031019C; // Window Handler of Notepad
char szBuf[4096];
HWND hwndEdit;
LRESULT result;
hwndEdit = FindWindowEx(hwnd, NULL, L"Edit", NULL); // Class for edit box
result = SendMessage(hwndEdit, WM_GETTEXT, sizeof(szBuf) / sizeof(szBuf[0]), (LPARAM)szBuf);
cout<<"Contents: \n"<<result;
cin.get();
return 0;
}
I tried print_f, but it outputs unreadable characters:
printf( "Contents: %s\n", result, szBuf );
It looks to me like you probably have a little bit of a mismatch happening.
Based on the L"Edit", you seem to be doing a Unicode build (otherwise, you'd get an error message about not being able to convert an wchar_t const[5] to LPCSTR, and the code wouldn't compile.
If you do a Unicode build, however, WM_GETTEXT is going to write Unicode data to your buffer, so you need to prepare for and use Unicode instead of narrow characters for your buffer.
For convenience, I've modified it a little to find Notepad instead of using a hard-coded Window handle.
#include <windows.h>
#include <stdio.h>
#define elements(b) (sizeof(b)/sizeof(b[0]))
int main() {
HWND hwnd; // Window Handler of Notepad
wchar_t buf[4096]={0};
HWND hwndEdit;
LRESULT result;
hwnd=FindWindowEx(NULL, NULL, L"Notepad", NULL);
hwndEdit=FindWindowEx(hwnd, NULL, L"Edit", NULL); // Class for edit box
result = SendMessage(hwndEdit, WM_GETTEXT, elements(buf), (LPARAM)buf);
printf("%S", buf);
return 0;
}
I built with:
cl /DUNICODE whatever.cpp user32.lib
Then I did a quick test that printed out exactly the text I'd typed into Notepad. To verify the result, I then edited the text in notepad, ran it again, and it printed out the modified text.
I want the write the current window title in console and/or file, and I have trouble with LPWSTR to char * or const char *. My code is:
LPWSTR title = new WCHAR();
HWND handle = GetForegroundWindow();
GetWindowText(handle, title, GetWindowTextLength( handle )+1);
/*Problem is here */
char * CSTitle ???<??? title
std::cout << CSTitle;
FILE *file;
file=fopen("file.txt","a+");
fputs(CSTitle,file);
fclose(file);
You are only allocating enough memory for one character, not the entire string. When GetWindowText is called it copies more characters than there is memory for causing undefined behavior. You can use std::string to make sure there is enough memory available and avoid managing memory yourself.
#include <string>
HWND handle = GetForegroundWindow();
int bufsize = GetWindowTextLength(handle);
std::basic_string<TCHAR> title(bufsize, 0);
GetWindowText(handle, &title[0], bufsize + 1);
You need to allocate enough memory for storing title:
HWND handle = GetForegroundWindow();
int bufsize = GetWindowTextLength(handle) + 1;
LPWSTR title = new WCHAR[bufsize];
GetWindowText(handle, title, bufsize);