Linq Select Statement wont work

I am getting the following error when running the following query

public int getPinCount(int terminalId, ref int pinnumber)
{
         using (var开发者_JAVA技巧 dbEntities = new DatabaseAccess.Schema.BMIEntityModel())
         {
              DateTime dateNow = DateTime.Now;
              return (from pins in dbEntities.PinIds
                              where pin.TerminalID.Equals((int)terminalId) 
                              && pin.PinExpireDateTime < (DateTime)dateNow
                              select pins).Count();
         }
         return 0;
}

Unable to create a constant value of type 'System.Object'. Only primitive types ('such as Int32, String, and Guid') are supported in this context.

• TerminalId = int
• PinExpireDateTime = datetime

Any ideas?

If you're comparing ints in: pin.TerminalID.Equals((int)terminalId) cast it before query and use ==.

Assuming that terminalId is int

pins.TerminalID == terminalId

I dont understand why are u casting dateNow to DateTime it's not needed since it's already DateTime.

Couple things I notice here.

1. You've used both pins and pin, but I think they're supposed to be the same identifier. This could just be a typo from copying your code into your question.

2. You've got some unnecessary explicit casts, and you're using the Equals method instead of just ==. I'm not sure why you're doing that. Equals is overridden for Int32, so it should be the same as using the == operator; it should work fine -- but I'm not sure where else this error could come from. It's possible that LINQ to Entities isn't able to support pushing Int32.Equals(int) to a SQL query, even though it supports Int32.== just fine.

The only other possibility I can think of is that pin.TerminalID or pin.PinExpireDateTime might not be the exact datatypes you think they are, but you'll have to check that yourself.

Either way, you can at least simplify your code:

public int getPinCount(int terminalId, ref int pinnumber)
{
     using (var dbEntities = new DatabaseAccess.Schema.BMIEntityModel())
     {
          DateTime dateNow = DateTime.Now;
          return (from pin in dbEntities.PinIds
                  where pin.TerminalID == terminalId
                  && pin.PinExpireDateTime < dateNow
                  select pin).Count();
     }
     return 0;
}