c++ - How to typecast wxObject to wxVariant? -

i have map of wxobject..but want typecast wxvariant.

void mwdataviewtable::initcolumnvalues(wxstring targetcolumn,wxstring sourcecolumn , std::map<wxobject,wxobject> srctargetvalue) {     wxvariant srcvalue;     wxvariant tgtvalue;     int srccolumnpos = getcolumnposition(sourcecolumn);     int tgtcolumnpos = getcolumnposition(targetcolumn);     int rows = m_rowdatalist.size()-1;  //without header     for(int i=0;i< rows;i++)     {                getvalue(srcvalue,i,srccolumnpos);         tgtvalue = (wxvariant)srctargetvalue[srcvalue] ;// typecasting         setvalue(tgtvalue,i,tgtcolumnpos/*toggle-column*/);     }  } 

in highlighted line doing typecasting..but giving me error says "error 1 error c2678: binary '<' : no operator found takes left-hand operand of type 'const wxobject'" error coming in xstddef.h file. dont have idea why happening or if typecasting wrongly. please..!

in std::map, key values used sort , uniquely identify elements.

in code both key , value of wxobject type. wxobject class doesn't seems overload less operator method ( have no idea these wx objects are).

std::map requires less operator method perform comparison required sorting key values. should either pass own comparison function std::map compare 2 wxobjects.

the template container std::map takes compare function third agument.

template < class key,                                     // map::key_type            class t,                                       // map::mapped_type            class compare = less<key>,                     // map::key_compare            class alloc = allocator<pair<const key,t> >    // map::allocator_type            > class map;  

compare binary predicate have follwing definition in case:

bool mycompare( const wxobject& , const wxobject&) {   \\compare logic returns true or false } 

you can have own map using compare method:

typedef std::map<wxobject,wxobject,&mycompare> mymap; mymap srctargetvalue;