Fix VB.NET build warning
Fix VB.NET build warning

H2ONaCl/oxyplot,freudenthal/oxyplot,Jonarw/oxyplot,Mitch-Connor/oxyplot,olegtarasov/oxyplot,svendu/oxyplot,bbqchickenrobot/oxyplot,TheAlmightyBob/oxyplot,objorke/oxyplot,as-zhuravlev/oxyplot_wpf_fork,Rustemt/oxyplot,NilesDavis/oxyplot,HermanEldering/oxyplot,shoelzer/oxyplot,ze-pequeno/oxyplot,objorke/oxyplot,shoelzer/oxyplot,olegtarasov/oxyplot,GeertvanHorrik/oxyplot,TheAlmightyBob/oxyplot,zur003/oxyplot,lynxkor/oxyplot,Kaplas80/oxyplot,lynxkor/oxyplot,mattleibow/oxyplot,Jofta/oxyplot,Isolocis/oxyplot,GeertvanHorrik/oxyplot,sevoku/oxyplot,shoelzer/oxyplot,br111an/oxyplot,Mitch-Connor/oxyplot,bbqchickenrobot/oxyplot,TheAlmightyBob/oxyplot,mattleibow/oxyplot,H2ONaCl/oxyplot,bbqchickenrobot/oxyplot,as-zhuravlev/oxyplot_wpf_fork,freudenthal/oxyplot,br111an/oxyplot,DotNetDoctor/oxyplot,Rustemt/oxyplot,br111an/oxyplot,sevoku/oxyplot,jeremyiverson/oxyplot,Sbosanquet/oxyplot,Mitch-Connor/oxyplot,jeremyiverson/oxyplot,Kaplas80/oxyplot,DotNetDoctor/oxyplot,BRER-TECH/oxyplot,as-zhuravlev/oxyplot_wpf_fork,GeertvanHorrik/oxyplot,jeremyiverson/oxyplot,Rustemt/oxyplot,H2ONaCl/oxyplot,Sbosanquet/oxyplot,svendu/oxyplot,lynxkor/oxyplot,svendu/oxyplot,HermanEldering/oxyplot,freudenthal/oxyplot,Sbosanquet/oxyplot,BRER-TECH/oxyplot,oxyplot/oxyplot,objorke/oxyplot