Question

Hello everybody my linq to sql selection does not working on dateTime field

 for (DateTime i = FromDate; i < DateTime.Now; i = i.AddDays(1))
            {
                var Count = (from d in db.Users
                             where d.RegistrationDate.Value == i
                             select d.ID).Count();
            }

i have tried i.date but it does not works too

Answer 1

It looks like you are trying to get a count of all users who registered on a certain day. If so, I think you are best off using the group keyword to group together all users by registration date. You can then create a new anonymous type to contain by the date, and the count, like so:

var Counts = (from d in db.Users
             // filter down to only users registered between FromDate and Now
             where (d.RegistrationDate.Value >= FromDate 
                 && d.RegistrationDate < DateTime.Now)
             // Group all users together by Date of registration (assuming 
             // RegistrationDate is a DateTime? field)
             group d by d.RegistrationDate.Value.Date into date
             // Get a new anonymous type that contains the date and the number
             // of users registered on that date
             select new { Date = date.Key, Count = date.Count() } );