c# LINQ to Entities does not recognize the method 'Boolean

Question

 How to  address Boolean method below. The value Online has to be set. The error I get is 

"c# LINQ to Entities does not recognize the method 'Boolean" 

 

foreach (var i in (from a in db.Color

join i in db.ColorClothes

on a.InstallationId equals i.InstallationId

where a.Id == Id

select

new

{

ID= i.id,

OnLine = Utilities.IsConnectionValid(i.InstallationId) ? true : false, I get the error right here

}).ToList())