Drag and Drop on a Tray Icon

//*********************************************************************************
//
// Title: Terminal Services Drag Drop
//
//*********************************************************************************
#define _UNICODE

#include "DDHook.h"
#include "ProcessData.h"

#include <Windowsx.h>	// MapWindowRect
#include <commctrl.h>

struct TRAYDATA
{
	HWND hwnd;				
	UINT uID;				
	UINT uCallbackMessage;	
	DWORD Reserved[2];		
	HICON hIcon;				
};

#define	DLL_EXPORT extern "C" __declspec(dllexport)

// Shared DATA
#pragma data_seg ( "SHAREDDATA" )

	// this is the total number of processes this dll is currently attached to
	int				iInstanceCount		= 0;
	HWND			g_hWnd				= 0;

#pragma data_seg ()

#pragma comment(linker, "/section:SHAREDDATA,rws")

bool			bHooked        = false;
HHOOK			hhook	       = 0;//msgs
HINSTANCE		hInst	       = 0;

BOOL APIENTRY DllMain( HINSTANCE hinstDLL, DWORD  ul_reason_for_call, LPVOID lpReserved )
{
    switch (ul_reason_for_call)
	{
		case DLL_PROCESS_ATTACH:
			{
				// remember our instance handle
				//OutputDebugString("DDHook dll loaded...");
				hInst = hinstDLL;
				++iInstanceCount;

				TCHAR szMsg[256] = {0};
				//wsprintf(szMsg,L"Tray Rectangle: %d-%d %d-%d",R.left,R.right,R.top,R.bottom);
				wsprintfW(szMsg,L"DDHook dll loaded...,iInstanceCount: %d", iInstanceCount);
				OutputDebugStringW(szMsg);

				 break;
			}
		case DLL_THREAD_ATTACH:
				break;
		case DLL_THREAD_DETACH:
			break;
		case DLL_PROCESS_DETACH:
			{
				//OutputDebugString("DDHook dll unloaded...");
				--iInstanceCount;
				
				
				TCHAR szMsg[256] = {0};
				//wsprintf(szMsg,L"Tray Rectangle: %d-%d %d-%d",R.left,R.right,R.top,R.bottom);
				wsprintfW(szMsg,L"DDHook dll unloaded...,iInstanceCount: %d", iInstanceCount);
				OutputDebugStringW(szMsg);

				//CloseVirtualChannel();
			}
			break;
    }

    return TRUE;
}

void QueryDragDropFileNames(HDROP hDrop)
{
	// this could be used later to actually drop stuff directly onto windows in the RDP session
	POINT pt = {0};
	if (DragQueryPoint(hDrop,&pt))
	{
		TCHAR szText1[MAX_PATH] = {0};
		wsprintfW(szText1,L"Dropped at pos: x[%d] y[%d]", pt.x,pt.y);
		OutputDebugStringW(szText1);
	}
	else
	{
		OutputDebugStringW(L"Failed to run DragQueryPoint()");
	}

	UINT cFiles = DragQueryFile(hDrop, 0xFFFFFFFF/*(UINT)-1*/, NULL, 0);	
	
	TCHAR szText[MAX_PATH] = {0};
	wsprintfW(szText,L"Drag/Drop %d files/directories:", cFiles);
	OutputDebugStringW(szText);

	for( UINT indx = 0; indx < cFiles; indx++ )
	{
		TCHAR szFile[MAX_PATH] = {0};
		UINT cChars = DragQueryFileW(hDrop, indx, szFile, sizeof(szFile));
		if (cChars > 0)
		{
			OutputDebugStringW(szFile);
		}
	}
}

HWND FindSysPagerWindow()
{
	HWND hWnd = FindWindowEx(GetDesktopWindow(), 0, "Shell_TrayWnd", NULL);
	if(hWnd)
	{
		hWnd = FindWindowEx(hWnd,NULL,"TrayNotifyWnd", NULL);
		if(hWnd)
		{
			hWnd = FindWindowEx(hWnd,NULL,"SysPager", NULL);
		}
	}
	return hWnd;
}

HWND FindTrayToolbarWindow()
{
	HWND hWnd = FindWindow("Shell_TrayWnd", NULL);
	if(hWnd)
	{
		hWnd = FindWindowEx(hWnd,NULL,"TrayNotifyWnd", NULL);
		if(hWnd)
		{
			hWnd = FindWindowEx(hWnd,NULL,"SysPager", NULL);
			if(hWnd)
			{				
				hWnd = FindWindowEx(hWnd, NULL,"ToolbarWindow32", NULL);
			}
		}
	}
	return hWnd;
}

BOOL FileDroppedAtIcon(const HWND a_hWndOwner, const int a_iButtonID, const PPOINT pPoint)
{
    HWND hWndTray = FindTrayToolbarWindow();

    //now we have to get an ID of the parent process for system tray
    DWORD dwTrayProcessID = -1;
    GetWindowThreadProcessId(hWndTray, &dwTrayProcessID);

    //here we get a handle to tray application process
    HANDLE hTrayProc = OpenProcess(PROCESS_ALL_ACCESS, 0, dwTrayProcessID);
 
    //now we check how many buttons is there - should be more than 0
    int iButtonsCount = SendMessage(hWndTray, TB_BUTTONCOUNT, 0, 0);

    //We want to get data from another process - it's not possible 
    //to just send messages like TB_GETBUTTON with a locally
    //allocated buffer for return data. Pointer to locally allocated 
    //data has no usefull meaning in a context of another
    //process (since Win95) - so we need 
    //to allocate some memory inside Tray process.
    //We allocate sizeof(TBBUTTON) bytes of memory - 
    //because TBBUTTON is the biggest structure we will fetch. 
    //But this buffer will be also used to get smaller 
    //pieces of data like RECT structures.
    LPVOID lpData = VirtualAllocEx(hTrayProc, NULL, 
                    sizeof(TBBUTTON), MEM_COMMIT, PAGE_READWRITE);

    BOOL bIconFound = FALSE;

    for(int iButton=0; iButton<iButtonsCount; iButton++)
    {
        //first let's read TBUTTON information 
        //about each button in a task bar of tray

        DWORD dwBytesRead = -1;
        TBBUTTON buttonData;
        SendMessage(hWndTray, TB_GETBUTTON, iButton, (LPARAM)lpData);

        //we filled lpData with details of iButton icon of toolbar 
        //- now let's copy this data from tray application
        //back to our process
        ReadProcessMemory(hTrayProc, lpData, &buttonData, sizeof(TBBUTTON), &dwBytesRead);

        //let's read extra data of each button: 
        //there will be a HWND of the window that 
        //created an icon and icon ID
        DWORD dwExtraData[2] = { 0,0 };
        ReadProcessMemory(hTrayProc, (LPVOID)buttonData.dwData,dwExtraData, sizeof(dwExtraData), &dwBytesRead);

        HWND hWndOfIconOwner = (HWND) dwExtraData[0];
        int  iIconId         = (int)  dwExtraData[1];

        if(hWndOfIconOwner != a_hWndOwner || iIconId != a_iButtonID)
        {
            continue;
        }

        //we found our icon - in WinXP it could be hidden - let's check it:
        if( buttonData.fsState & TBSTATE_HIDDEN )
        {
            break;
        }

        //now just ask a tool bar of rectangle of our icon
        RECT rcPosition = {0,0};
        SendMessage(hWndTray, TB_GETITEMRECT, iButton, (LPARAM)lpData);
       // ReadProcessMemory(hTrayProc, lpData, lprcPosition/*&rcPosition*/, sizeof(RECT), &dwBytesRead);
		ReadProcessMemory(hTrayProc, lpData, &rcPosition, sizeof(RECT), &dwBytesRead);

		MapWindowRect(hWndTray,NULL,&rcPosition);

		if (pPoint->x > rcPosition.left && pPoint->x < rcPosition.right &&
			pPoint->y > rcPosition.top && pPoint->y < rcPosition.bottom)
		{
			OutputDebugString("Stuff dropped at our icon...!!!");	

			bIconFound = TRUE;
			break;
		}

        break;
    }

    VirtualFreeEx(hTrayProc, lpData, NULL, MEM_RELEASE);
    CloseHandle(hTrayProc);

    return bIconFound;
}

LRESULT CALLBACK GetMsgProc(UINT nCode, WPARAM wParam, LPARAM lParam)
{
	if (nCode == HC_ACTION) 
	{
		MSG* msg = (MSG*)lParam;
		HWND hWnd = msg->hwnd;

		if (msg->message == WM_DROPFILES)
		{
			OutputDebugString("WM_DROPFILES received"); 

			TCHAR szText1[MAX_PATH] = {0};
			wsprintfW(szText1,L"nCode: [%d] wParam: [%d] lParam: [%d]",nCode,wParam,lParam);
			OutputDebugStringW(szText1);

			RECT R_DROP = {0};
			GetWindowRect( msg->hwnd, &R_DROP );

			TCHAR szMsg[256] = {0};
			wsprintfW(szMsg,L"DropRectangle: %d-%d %d-%d",R_DROP.left,R_DROP.right,R_DROP.top,R_DROP.bottom);
			OutputDebugStringW(szMsg);

			wsprintfW(szMsg,L"DropPoint: x:%d y:%d",msg->pt.x,msg->pt.y);
			OutputDebugStringW(szMsg);

			wsprintfW(szMsg,L"nCode: [%d] wParam: [%d] lParam: [%d]",msg->time,msg->wParam,msg->lParam);
			OutputDebugStringW(szMsg);

			HWND hSysPager = FindSysPagerWindow();
			if (hSysPager != NULL)
			{				
				RECT R2 = {0};
				GetWindowRect( hSysPager, &R2 );

				// check if the drop area is the same as the tray area...
				if (R_DROP.left == R2.left &&
					R_DROP.right == R2.right &&
					R_DROP.bottom == R2.bottom &&
					R_DROP.top == R2.top)
				{
					HWND hToolbarWindow32 = FindTrayToolbarWindow();
					if (hToolbarWindow32)
					{
						DWORD dwTrayPid = 0;
						GetWindowThreadProcessId(hToolbarWindow32, &dwTrayPid);

						int count = (int)SendMessage(hToolbarWindow32, TB_BUTTONCOUNT, 0, 0);
						CProcessData<TBBUTTON> data(dwTrayPid);
						TBBUTTON tb = {0};
						TRAYDATA tray = {0};

						for(int i=0; i<count; i++)
						{		
							SendMessage(hToolbarWindow32, TB_GETBUTTON, i, (LPARAM)data.GetData());		
							data.ReadData(&tb);			
							data.ReadData<TRAYDATA>(&tray,(LPCVOID)tb.dwData);

							if (tray.hwnd == g_hWnd && FileDroppedAtIcon(g_hWnd,i,&msg->pt))
							{
								SendMessage(g_hWnd,msg->message,msg->wParam,msg->lParam);
							}
						}
					}
				}
			}
		}
	}
	else
	{
		//return CallNextHookEx(hhook, nCode, wParam, lParam);
	}

	return CallNextHookEx(hhook, nCode, wParam, lParam);
}

DLL_EXPORT void SetMsgHook(HWND hWnd)
{
	if (!bHooked)
	{
		hhook	= SetWindowsHookEx(WH_GETMESSAGE, (HOOKPROC)GetMsgProc, hInst, (DWORD)NULL);
		bHooked	= true;	

		g_hWnd  = hWnd;
	}
}

DLL_EXPORT	void RemoveMsgHook(void)
{
	if (bHooked) 
	{
		UnhookWindowsHookEx(hhook);	
		bHooked = false;

		g_hWnd  = NULL;
	}
}

DLL_EXPORT int GetInstanceCount()
{
	return iInstanceCount;
}