Undocumented API ITrayNotify.

ITrayNotify.cpp

#include <tchar.h>
#include <windows.h>

// The known values for NOTIFYITEM's dwPreference member.
enum NOTIFYITEM_PREFERENCE
{
	// In Windows UI: "Only show notifications."
	PREFERENCE_SHOW_WHEN_ACTIVE = 0,
	// In Windows UI: "Hide icon and notifications."
	PREFERENCE_SHOW_NEVER = 1,
	// In Windows UI: "Show icon and notifications."
	PREFERENCE_SHOW_ALWAYS = 2
};

typedef struct tagNOTIFYITEM
{
	PWSTR pszExeName;
	PWSTR pszTip;
	HICON hIcon;
	HWND hWnd;
	NOTIFYITEM_PREFERENCE dwPreference;
	UINT uID;
	GUID guidItem;
} NOTIFYITEM, *PNOTIFYITEM;

MIDL_INTERFACE("D782CCBA-AFB0-43F1-94DB-FDA3779EACCB") INotificationCB : public IUnknown
{
public:
	BEGIN_INTERFACE
	virtual HRESULT STDMETHODCALLTYPE Notify(ULONG, NOTIFYITEM *) = 0;
	END_INTERFACE
};

MIDL_INTERFACE("FB852B2C-6BAD-4605-9551-F15F87830935") ITrayNotify : public IUnknown
{
public:
	BEGIN_INTERFACE
	virtual HRESULT STDMETHODCALLTYPE RegisterCallback(INotificationCB* callback) = 0;
	virtual HRESULT STDMETHODCALLTYPE SetPreference(const NOTIFYITEM* notify_item) = 0;
	virtual HRESULT STDMETHODCALLTYPE EnableAutoTray(BOOL enabled) = 0;
	END_INTERFACE
};

MIDL_INTERFACE("D133CE13-3537-48BA-93A7-AFCD5D2053B4") ITrayNotifyWin8 : public IUnknown
{
public:
	BEGIN_INTERFACE
	virtual HRESULT STDMETHODCALLTYPE RegisterCallback(INotificationCB* callback, ULONG*) = 0;
	virtual HRESULT STDMETHODCALLTYPE UnregisterCallback(ULONG*) = 0;
	virtual HRESULT STDMETHODCALLTYPE SetPreference(NOTIFYITEM const*) = 0;
	virtual HRESULT STDMETHODCALLTYPE EnableAutoTray(BOOL) = 0;
	virtual HRESULT STDMETHODCALLTYPE DoAction(BOOL) = 0;
	END_INTERFACE
};

const CLSID CLSID_TrayNotify = { 0x25DEAD04, 0x1EAC, 0x4911,{ 0x9E, 0x3A, 0xAD, 0x0A, 0x4A, 0xB5, 0x60, 0xFD } };

template <class T>
class NotificationMgr : public INotificationCB
{
public:
	NotificationMgr(T *pTrayNotify) : m_pTrayNotify(pTrayNotify) {}

	IFACEMETHODIMP QueryInterface(REFIID riid, PVOID *ppv)
	{
		if (ppv == nullptr)
			return E_POINTER;

		if (riid == IID_IUnknown)
			*ppv = static_cast<IUnknown *>(this);
		else if (riid == __uuidof (INotificationCB))
			*ppv = static_cast<INotificationCB *>(this);
		else
			return E_NOINTERFACE;

		reinterpret_cast<IUnknown*>(*ppv)->AddRef();

		return S_OK;
	}

	IFACEMETHODIMP_(ULONG) AddRef() { return 1; }

	IFACEMETHODIMP_(ULONG) Release() { return 1; }

	IFACEMETHODIMP Notify(ULONG Event, NOTIFYITEM *NotifyItem)
	{
		wchar_t *copy = _wcsdup(NotifyItem->pszExeName);
		if (copy)
		{
			_wcslwr_s(copy, wcslen(NotifyItem->pszExeName) + 1);
			if (wcsstr(copy, L"telegram.exe"))
			{
				if (m_pTrayNotify)
				{
					NotifyItem->dwPreference = PREFERENCE_SHOW_ALWAYS;
					m_pTrayNotify->SetPreference(NotifyItem);
				}
			}
			free(copy);
		}
		return S_OK;
	}
private:
	T *m_pTrayNotify;
};

int main()
{
	CoInitialize(nullptr);
	IUnknown *pIUnk;
	HRESULT hr = CoCreateInstance(CLSID_TrayNotify, nullptr, CLSCTX_LOCAL_SERVER, IID_PPV_ARGS(&pIUnk));

	if (SUCCEEDED(hr))
	{
		ITrayNotifyWin8 *pTrayNotifyW8;
		hr = pIUnk->QueryInterface(&pTrayNotifyW8);
		if (SUCCEEDED(hr))
		{
			ULONG callback_id = 0;
			NotificationMgr<ITrayNotifyWin8> NotiMgr8(pTrayNotifyW8);
			hr = pTrayNotifyW8->RegisterCallback(&NotiMgr8, &callback_id);
			if (SUCCEEDED(hr))
				hr = pTrayNotifyW8->UnregisterCallback(&callback_id);
			pTrayNotifyW8->Release();
		}
		else
		{
			ITrayNotify *pTrayNotify;
			hr = pIUnk->QueryInterface(&pTrayNotify);
			if (SUCCEEDED(hr))
			{
				NotificationMgr<ITrayNotify> NotiMgr(pTrayNotify);
				hr = pTrayNotify->RegisterCallback(&NotiMgr);
				if (SUCCEEDED(hr))
					pTrayNotify->RegisterCallback(nullptr);
				pTrayNotify->Release();
			}
		}
		pIUnk->Release();
	}

	return 0;
}

Tested on Windows 10 x64 15063.674.
References:
https://chromium.googlesource.com/chromium/src.git/+/master/chrome/browser/ui/views/status_icons/
https://bbs.pediy.com/thread-202658.htm

C++写出C#风格
WinAPI COM模板编程

第一次见，好...好厉害....

no effect on windows 10 Version 1709 (OS Build 16299.125)

could you pls update it to work with win10 1803 (17134.1)?

i used a similar app (below link) but it stopped working since version 1709 in december
https://hianz.wordpress.com/2013/09/03/new-windows-tray-notification-manager-is-here/

typedef struct tagNOTIFYITEM {
PWSTR lpszExeName; <---- Causing crash
PWSTR lpszTip; <---- or this Causing crash
HICON hIcon;
HWND hWnd;
NOTIFYITEM_PREFERENCE dwPreference;
UINT uID;
GUID guidItem;
} NOTIFYITEM;

This structure causing fatal crash in vb6 on Win11 Home Edition.