Lotus notes Formula. trying to run an @command inside of a fields validation -

i trying use formula open document within field when comes validation. have set database checks duplicate entries , want database (if form created) check doesn't exist , if ask user if wants open form. have got set , acquired unid when come save document test (with working perfectly) gives following error

@commands , other ui functions not allowed in context 

not sure try. appreciate. command used follows

@command([editdocument];1;unid) //where unid id have acquired 

task, cannot done formula language. message sais: @commands cannot used in of contexts task.

you need use lotusscript in matching event (e.g. querysave) check , open other document. here example code:

%include "lsconst.lss" sub querysave( source notesuidocument, continue variant )   dim ses new notessession   dim db notesdatabase   dim ws new notesuiworkspace   dim doc notesdocument   dim ok variant   dim strotherunid string   set db = ses.currentdatabase   strotherunid = source.document.otherunid(0)   if strotherunid  <> ""     continue = false     ok = messagebox ("there document, want edit it?" , mb_yesno + mb_iconquestion, "question" )     if ok = idyes       set doc = db.getdocumentbyunid( strotherunid )       call ws.editdocument( false, doc )     end if   end if end sub 

this code not tested @ all, used starting point. needs field called "otherunid" contains universalid of other document.