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).
Related
I want to get HWND in ATL DLL for SendMessage or PostMessage function in Thread.
but, ATL DLL doesn't have a window.
How to get HWND in ATL DLL?
Project Application Setting : DLL(Dynamic-link library), Security Development Lifecycle, ('not' Support MFC)
Class Option : Apartment, Aggregation Yes, Dual InterFace, Connection points.
HelloCtrl.cpp (VB Client is Handling ShowMessage())
STDMETHODIMP CHelloCtrl::ShowMessage(BSTR bstrCaption, VARIANT_BOOL* lpvbResult)
{
DWORD dwThreadID;
m_hThread_ReadData = CreateThread(NULL, 0, T_ReadData, (LPVOID)this, 0, &dwThreadID);
return S_OK;
}
DWORD WINAPI CHelloCtrl::T_ReadData(LPVOID pParam)
{
CHelloCtrl* hCtrl = (CHelloCtrl*) pParam;
::PostMessage(hCtrl->m_hWnd, WM_KEYDOWN, (WPARAM)NULL, (LPARAM)NULL);
return S_OK;
}
void CHelloCtrl::LeftButton()
{
Fire_OnMouseClick(123, 123);
}
HelloCtrl.h
#define WM_THREADFIREEVENT (WM_USER+1)
BEGIN_MSG_MAP(CHelloCtrl)
CHAIN_MSG_MAP(CComControl<CHelloCtrl>)
DEFAULT_REFLECTION_HANDLER()
MESSAGE_HANDLER(WM_THREADFIREEVENT, OnLeftButtonDown)
END_MSG_MAP()
public:
STDMETHOD(ShowMessage)(BSTR bstrCaption, VARIANT_BOOL* lpvbResult);
LRESULT OnLeftButtonDown(UINT /*uMsg*/, WPARAM /*wParam*/, LPARAM /*lParam*/, BOOL& /*bHandled*/);
void LeftButton();
private:
HANDLE m_hThread_ReadData;
static DWORD WINAPI T_ReadData(LPVOID pParam);
Window is an object that a process or module might have or might not have, or it might create one if needed. That is, your question does not have an answer without specifying what kind of window and its HWND handle you are looking for. DLL and HWND are unrelated.
From the context, it looks like you want a window which you can use for messaging and to transfer execution control between threads. That is, you post somewhere then handle elsewhere leaving the threading magic to window API.
In this case you can either reuse one of existing windows, such as window created for an ActiveX control, our you simply create your own window you fully control and use for your purposes. For the latter you derive from CWindowImpl and... see Implementing a Window with CWindowImpl. The former might be simpler might be not: ActiveX controls don't have to have a window in which case they are windowless controls. In the same time, you have an option to force windowed control using m_bWindowOnly, see How do I get the HWND for an ActiveX control after the control has been initialised/activated?.
I'm trying to enumerate all win32 windows using following code:
EnumChildWindows(GetDesktopWindow(),
WindowManager::enumChildWindows,
reinterpret_cast<LPARAM>(this));
BOOL CALLBACK WindowManager::enumChildWindows(HWND hwnd, LPARAM lParam) {
WindowManager* manager = reinterpret_cast<WindowManager*>(lParam);
//
// Do stuff with child window handle (hwnd)
//
// Return TRUE to continue enumeration, FALSE to stop.
return TRUE;
}
So basically, I get the top most window by calling GetDesktopWindow( VOID ) function from WinAPI and enumerate child windows by calling EnumChildWindows( __in_opt HWND hWndParent, __in WNDENUMPROC lpEnumFunc, __in LPARAM lParam) function again from WinAPI.
Simply, my question is, can I be missing any win32 window by this approach? Could anyone hide a win32 window such that this approach can't enumerate it?
Thanks in advance.
For your way (via EnumChildWindows(GetDesktopWindow)) - it is possible: just create message-only window.
P.S. But you can enumerate message-only windows via EnumChildWindows(GetAncestor(FindWindowEx(HWND_MESSAGE,0,0,0),GA_PARENT)): see How come FindWindow finds a window that EnumChildWindows doesn't?.
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);
I had to rewrite a custom file dialog (derived from MFC's CFileDialog) to WTL's CFileDialog. I have a bit of a problem to retrieve data when I don't have access to the dialog object itself. Imagine the following.
I have a member in the class
static WNDPROC m_wndProc;
I initialize it in the following static member fnct.
void CMyFileDialog::OnInitDone(LPOFNOTIFY lpon)
{
m_wndProc = (WNDPROC)::SetWindowLong(thisHWND, GWL_WNDPROC, reinterpret_cast<long>
(&CMyFileDialog::WndProcSelect));
}
The handle comes into the callback method with no problem and I can "connect" to it with CWindow
LRESULT CALLBACK CMyFileDialog::WndProcSelect(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
// ...
CWindow callerWnd(hwnd);
}
And here, I don't know the real methodology to convert the CWindow to my CMyFileDialog. As I think, this CWindow class is just connected somehow to the handle itself, but does not the same object as it was created before. So for example, if I have a CString or other members in my CMyFileDialog, it won't access its state, because it was created in another object.
I think you are doing something wrong here. You have access to the message map without having to modify the WndProc (that is something that the CFileDialogImpl will have already done).
See for example http://www.codeproject.com/Articles/12999/WTL-for-MFC-Programmers-Part-IX-GDI-Classes-Common#usingcfiledialog, where they simply
BEGIN_MSG_MAP(CMyFileDialog)
CHAIN_MSG_MAP(CFileDialogImpl<CMyFileDialog>)
END_MSG_MAP()
You could always use SetWindowLongPtr with your "this" pointer, then it would be fairly easy to extract the pointer to your CMyFileDialog.
I'm developing a plugin (a dll that is loaded by other app). There's a special function that should return HWND so that app can show a dialog. The problem is that I don't know from where I can get the hInstance (it's not passed as a parameter to the function).
Looks like I'm not understanding something, I'm new to all this stuff, so forgive if the question is silly.
UPD: tried to get hInstance with getModuleHandle:
void* createLoginDialog() {
HINSTANCE hIns = (HINSTANCE) GetModuleHandle(L"comapping");
HWND hWnd = CreateWindow(L"Popup",
L"Enter login",
WS_POPUP,
20,
20,
20,
20,
NULL,
NULL,
hIns,
NULL);
return hWnd;
}
I'm still getting Access Violation.
Several ways to get it:
The first argument passed to your DllMain() entrypoint, cast to HINSTANCE
GetModuleHandle() using your DLL name, cast to HINSTANCE
VirtualQuery(), passing the address of your function. Cast the returned MEMORY_BASIC_INFORMATION.BaseAddress to HINSTANCE. Works on both 32-bit and 64-bit versions of Windows.
According to the documentation of CreateWindow, the hInstance argument is optional. This means that it's valid to pass NULL here. However, as Simon Richter points out in the comments to this answer, the argument may only be NULL the window class is registered globally.
If you're writing a DLL, you may just as well define a DllMain entry point function yourself. This function is called by Windows, passing the handle of your function as the first arugment. You can memorize this handle somewhere to reuse it when creating your window.