c# - Shell extension - on the explorer window -

i'm creating shell extension in c# using microsoft source code registering , unregistering shell context menu handler.

the registration looks that:

    public static void registershellextcontextmenuhandler(guid clsid,          string filetype, string friendlyname)     {         if (clsid == guid.empty)         {             throw new argumentexception("clsid must not empty");         }         if (string.isnullorempty(filetype))         {             throw new argumentexception("filetype must not null or empty");         }          // if filetype starts '.', try read default value of          // hkcr\<file type> key contains progid file type          // linked.         if (filetype.startswith("."))         {             using (registrykey key = registry.classesroot.opensubkey(filetype))             {                 if (key != null)                 {                     // if key exists , default value not empty, use                      // progid file type.                     string defaultval = key.getvalue(null) string;                     if (!string.isnullorempty(defaultval))                     {                         filetype = defaultval;                     }                 }             }         }          // create key hkcr\<file type>\shellex\contextmenuhandlers\{<clsid>}.         string keyname = string.format(@"{0}\shellex\contextmenuhandlers\{1}",             filetype, clsid.tostring("b"));         using (registrykey key = registry.classesroot.createsubkey(keyname))         {             // set default value of key.             if (key != null && !string.isnullorempty(friendlyname))             {                 key.setvalue(null, friendlyname);             }         }     } 

the second parameter file type extenstion work on , example i'm passing that:

  shellextreg.registershellextcontextmenuhandler(t.guid, ".cs",                  "csshellextcontextmenuhandler.filecontextmenuext class"); 

if want folder , not file type pass "directory"

my question how can make extension work when right click on explorer window self , not on specific file or folder