Windows Shell: Add custom context menu to a specified position

Question

I'm working on a custom context menu, and I was able to register it and it shows in the file explorer, but I want to put it next to another existed context menu.

But the position is not what I want. I want to put it another position:

Any ideas? Thanks.

---

Add the source code here:

It's a sample downloaded from: https://www.codeproject.com/Articles/583726/Writing-a-shell-extension-in-plain-Cplusplus

ShellExt.cpp

// ShellExt.cpp: implementation of the CShellExt class.
//
//////////////////////////////////////////////////////////////////////
#include <windows.h>
#include <tchar.h>
#include <shlobj.h>

#include "ShellExt.h"
#include "Guid.h"

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

CShellExt::CShellExt()
{

}

CShellExt::~CShellExt()
{

}

STDMETHODIMP_(DWORD) CShellExt::Release(void)
{
    if(--m_ObjRefCount == 0)
    {
        delete this;
        return 0;
    }

    return m_ObjRefCount;
}

STDMETHODIMP_(DWORD) CShellExt::AddRef(void)
{
    return ++m_ObjRefCount;
}

STDMETHODIMP CShellExt::QueryInterface(REFIID riid, LPVOID *ppReturn )
{
    *ppReturn = NULL;

    if( IsEqualIID(riid, IID_IUnknown) )
        *ppReturn = this;
    else if( IsEqualIID(riid, IID_IClassFactory) )
        *ppReturn = (IClassFactory*)this;
    else if ( IsEqualIID(riid, IID_IShellExtInit))
        *ppReturn = (IShellExtInit*)this;
    else if ( IsEqualIID(riid, IID_IContextMenu))
        *ppReturn = (IContextMenu*)this;


    if( *ppReturn )
    {
        LPUNKNOWN pUnk = (LPUNKNOWN)(*ppReturn);
        pUnk->AddRef();
        return S_OK;
    }

    return E_NOINTERFACE;
}

STDMETHODIMP CShellExt::Initialize (
    LPCITEMIDLIST pidlFolder, LPDATAOBJECT pDataObj, HKEY hProgID )
{
    FORMATETC fmt = { CF_HDROP, NULL, DVASPECT_CONTENT, -1, TYMED_HGLOBAL };
    STGMEDIUM stg = { TYMED_HGLOBAL };
    HDROP     hDrop;

    // Look for CF_HDROP data in the data object.
    if ( FAILED( pDataObj->GetData ( &fmt, &stg ) ))
    {
        // Nope! Return an "invalid argument" error back to Explorer.
        return E_INVALIDARG;
    }

    // Get a pointer to the actual data.
    hDrop = (HDROP) GlobalLock ( stg.hGlobal );

    // Make sure it worked.
    if ( NULL == hDrop )
        return E_INVALIDARG;

    // Sanity check - make sure there is at least one filename.
    UINT uNumFiles = DragQueryFile ( hDrop, 0xFFFFFFFF, NULL, 0 );
    HRESULT hr = S_OK;

    if ( 0 == uNumFiles )
    {
        GlobalUnlock ( stg.hGlobal );
        ReleaseStgMedium ( &stg );
        return E_INVALIDARG;
    }

    // Get the name of the first file and store it in our member variable m_szFile.
    if ( 0 == DragQueryFile ( hDrop, 0, m_szFile, MAX_PATH ) )
        hr = E_INVALIDARG;

    GlobalUnlock ( stg.hGlobal );
    ReleaseStgMedium ( &stg );

    return hr;
}

STDMETHODIMP CShellExt::QueryContextMenu (
    HMENU hmenu, UINT uMenuIndex, UINT uidFirstCmd,
    UINT uidLastCmd, UINT uFlags )
{
    // If the flags include CMF_DEFAULTONLY then we shouldn't do anything.
    if ( uFlags & CMF_DEFAULTONLY )
        return MAKE_HRESULT ( SEVERITY_SUCCESS, FACILITY_NULL, 0 );

    InsertMenu ( hmenu, uMenuIndex, MF_BYPOSITION, uidFirstCmd, _T("HelloExtNoAtl Test Item") );

    return MAKE_HRESULT ( SEVERITY_SUCCESS, FACILITY_NULL, 1 );
}

STDMETHODIMP CShellExt::GetCommandString (
    UINT_PTR idCmd, UINT uFlags, UINT* pwReserved, LPSTR pszName, UINT cchMax )
{
    //USES_CONVERSION;

    // Check idCmd, it must be 0 since we have only one menu item.
    if ( 0 != idCmd )
        return E_INVALIDARG;




    // If Explorer is asking for a help string, copy our string into the
    // supplied buffer.
    if ( uFlags & GCS_HELPTEXT )
    {
        LPCTSTR szText = _T("This is the simple shell extension's help");

        if ( uFlags & GCS_UNICODE )
        {   
            DWORD len;
            // Get the length (in wide chars) of the UNICODE buffer we'll need to
            // convert MyString to UNICODE.
            len = MultiByteToWideChar(CP_ACP, 0, szText, -1, 0, 0);
            
            BSTR  strptr;

            strptr = SysAllocStringLen(0, len);
            
            // Convert MyString to UNICODE in the buffer allocated by SysAllocStr
            MultiByteToWideChar(CP_ACP, 0, szText, -1, strptr, len);

            // We need to cast pszName to a Unicode string, and then use the
            // Unicode string copy API.
            lstrcpynW ( (LPWSTR) pszName, (LPWSTR)(strptr), cchMax );

            SysFreeString(strptr);
        }
        else
        {
            // Use the ANSI string copy API to return the help string.
            lstrcpynA ( pszName, (LPSTR)szText, cchMax );
        }

        return S_OK;
    }

    return E_INVALIDARG;
}

STDMETHODIMP CShellExt::InvokeCommand ( LPCMINVOKECOMMANDINFO pCmdInfo )
{
    // If lpVerb really points to a string, ignore this function call and bail out.
    if ( 0 != HIWORD( pCmdInfo->lpVerb ) )
        return E_INVALIDARG;

    // Get the command index - the only valid one is 0.
    switch ( LOWORD( pCmdInfo->lpVerb) )
    {
    case 0:
        {
            TCHAR szMsg [MAX_PATH + 32];

            wsprintf ( szMsg, _T("The selected file was:\n\n%s"), m_szFile );

            MessageBox ( pCmdInfo->hwnd, szMsg, _T("HelloShlExt"),
                MB_ICONINFORMATION );

            return S_OK;
        }
        break;

    default:
        return E_INVALIDARG;
        break;
    }
}

STDAPI DllRegisterServer( VOID )
{
    INT i;
    HKEY hKey;
    LRESULT lResult;
    DWORD dwDisp;
    TCHAR szSubKey[MAX_PATH];
    TCHAR szCLSID[MAX_PATH];
    TCHAR szModule[MAX_PATH];
    LPWSTR pwsz;

    // get the CLSID in string form
    StringFromIID( CLSID_HelloExtNoAtl, &pwsz );

    if( pwsz )
    {
        WideCharToLocal( szCLSID, pwsz, ARRAYSIZE(szCLSID) );
        LPMALLOC pMalloc;
        CoGetMalloc(1, &pMalloc);
        if( pMalloc )
        {
          pMalloc->Free(pwsz);
          pMalloc->Release();
        }
    }

    // get this DLL's path and file name
    GetModuleFileName( g_hInst, szModule, ARRAYSIZE(szModule) );

    // CLSID entries
    REGSTRUCT ClsidEntries[] = {  
        HKEY_CLASSES_ROOT, TEXT("CLSID\\%s"),                  NULL,                   TEXT("HelloExtNoAtl"),
        HKEY_CLASSES_ROOT, TEXT("CLSID\\%s"),                  TEXT("InfoTip"),        TEXT("HelloExtNoAtl."),
        HKEY_CLASSES_ROOT, TEXT("CLSID\\%s\\InprocServer32"),  NULL,                   TEXT("%s"),
        HKEY_CLASSES_ROOT, TEXT("CLSID\\%s\\InprocServer32"),  TEXT("ThreadingModel"), TEXT("Apartment"),
        HKEY_CLASSES_ROOT, TEXT("CLSID\\%s\\DefaultIcon"),     NULL,                   TEXT("%s,0"),
        NULL,              NULL,                               NULL,                   NULL};

    for( i=0; ClsidEntries[i].hRootKey; i++ )
    {
        // create the sub key string.
        wsprintf( szSubKey, ClsidEntries[i].lpszSubKey, szCLSID );
        lResult = RegCreateKeyEx(  ClsidEntries[i].hRootKey,
                              szSubKey,
                              0,
                              NULL,
                              REG_OPTION_NON_VOLATILE,
                              KEY_WRITE,
                              NULL,
                              &hKey,
                              &dwDisp );
   
        if( lResult==NOERROR )
        {
             TCHAR szData[MAX_PATH];
             wsprintf(szData, ClsidEntries[i].lpszData, szModule);
             lResult = RegSetValueEx( hKey,
                            ClsidEntries[i].lpszValueName,
                            0,
                            REG_SZ,
                            (LPBYTE)szData,
                            lstrlen(szData) + 1);
      
             RegCloseKey(hKey);
        }
        else
            return SELFREG_E_CLASS;
    }

    // Context Menu
    lstrcpy( szSubKey, TEXT("txtfile\\ShellEx\\ContextMenuHandlers\\HelloExtNoAtl"));
    lResult = RegCreateKeyEx(HKEY_CLASSES_ROOT,
        szSubKey,
        0,
        NULL,
        REG_OPTION_NON_VOLATILE,
        KEY_WRITE,
        NULL,
        &hKey,
        &dwDisp);

    if( lResult==NOERROR )
    {
        TCHAR szData[MAX_PATH];
        lstrcpy(szData, szCLSID);
        lResult = RegSetValueEx( hKey,
            NULL,
            0,
            REG_SZ,
            (LPBYTE)szData,
            lstrlen(szData) + 1);

        RegCloseKey(hKey);
    }
    else
        return SELFREG_E_CLASS;

   // register the extension as approved by NT
   OSVERSIONINFO  osvi;
   osvi.dwOSVersionInfoSize = sizeof(osvi);
   GetVersionEx( &osvi );

   if( VER_PLATFORM_WIN32_NT == osvi.dwPlatformId )
   {
       lstrcpy( szSubKey, TEXT("Software\\Microsoft\\Windows\\CurrentVersion\\Shell Extensions\\Approved"));
       lResult = RegCreateKeyEx(  HKEY_LOCAL_MACHINE,
                              szSubKey,
                              0,
                              NULL,
                              REG_OPTION_NON_VOLATILE,
                              KEY_WRITE,
                              NULL,
                              &hKey,
                              &dwDisp);

       if( lResult==NOERROR )
       {
           TCHAR szData[MAX_PATH];
           lstrcpy(szData, TEXT("HelloExtNoAtl"));
           lResult = RegSetValueEx( hKey,
                                 szCLSID,
                                 0,
                                 REG_SZ,
                                 (LPBYTE)szData,
                                 lstrlen(szData) + 1);
      
          RegCloseKey(hKey);
      }
      else
          return SELFREG_E_CLASS;
   }

   return S_OK;
}