HtmlEncode
Enabling HttpUtility for projects
By default your app probably can't see "System.Web.HttpUtility". You need to include a reference to System.Web.
Right-click your project in the Solution Explorer > Add Reference > Assemblies > Framework > Scroll to System.Web and enable it
Feel free to comment if you can add help to this page or point out issues and solutions you have found. I do not provide support on this site, if you need help with a problem head over to stack overflow.