Determine whether running in ASP.NET or WinForms/console without System.Web

From a class library, I need to determine at run-time whether I’m running in an ASP.NET app or a WinForms/console app. There have been several other questions asked on the subject, but all of those solutions require adding a reference to System.Web. If at all possible, when running my console and WinForms apps, I don’t want to load the System.Web assembly into memory just for one line of code out of thousands.

Can’t load System.Web.Cors assembly after call to Microsoft.Owin.Cors

When I check the System.Web.Cors assembly reference in the Solution Explorer, the Version is 5.2.3.0. The Specific Version property is set to False. The path is to the local project bin folder. When checking the .dll properties from the File Explorer, the file’s product version and file version. is also 5.2.3.