https://lviv.dotnet.city/2010/04/%d1%84%d0%b8%d0%bd%d0%b0%d0%bb%d1%8c%d0%bd%d0%b0%d1%8f-%d0%b2%d0%b5%d1%80%d1%81%d0%b8%d1%8f-silverlight-4-0/