. ▁The ▁library ▁is ▁written ▁in ▁C # ▁in ▁order ▁to ▁avoid ▁Windows ▁dependence . ▁At ▁the ▁Microsoft ▁Connect ▁event ▁on ▁December ▁ 4 , ▁ 2 0 1 8 , ▁Microsoft ▁announced ▁re le asing ▁of ▁Windows ▁Form s ▁as ▁open ▁source ▁project ▁on ▁GitHub . ▁It ▁is ▁released ▁under ▁the ▁M IT ▁License . ▁Windows ▁Form s ▁has ▁become ▁available ▁for ▁projects ▁target ing ▁the ▁. NET ▁Core ▁framework . ▁However , ▁the ▁framework ▁is ▁still ▁available ▁only ▁on ▁Windows ▁platform ▁and ▁the ▁Mon o ' s ▁incomplete ▁implementation ▁of ▁Win Forms ▁remains ▁the ▁only ▁cross - platform ▁implementation . ▁Windows ▁Pres entation ▁Foundation ▁a ▁graph ical ▁sub system ▁for ▁rendering ▁user ▁interfaces ▁in ▁Windows - based ▁applications ▁by ▁Microsoft . ▁It ▁is ▁based ▁on ▁Direct X ▁and ▁emp lo ys ▁X AML , ▁an ▁XML - based ▁language , ▁to ▁define ▁and ▁link ▁various ▁interface ▁elements . ▁WPF ▁applications ▁can ▁be ▁deployed ▁as ▁stand alone ▁desktop ▁programs ▁or ▁hosted ▁as ▁an ▁embedded ▁object ▁in ▁a ▁website . ▁At ▁the ▁Microsoft ▁Connect ▁event ▁on ▁December ▁ 4 , ▁ 2 0 1 8 , ▁Microsoft ▁announced ▁re le asing ▁of ▁WPF ▁as ▁open ▁source ▁project ▁on ▁GitHub . ▁It ▁is ▁released ▁under ▁the ▁M IT ▁License . ▁Windows ▁Pres entation ▁Foundation ▁has ▁become ▁available ▁for ▁projects ▁target ing ▁the ▁. NET ▁Core ▁framework . ▁However , ▁the ▁system ▁is ▁still ▁available ▁only ▁on ▁Windows ▁platform . ▁The ▁Windows ▁UI ▁Library ▁( Win UI ) ▁a ▁set ▁of ▁Microsoft ▁UI ▁controls ▁and