'Date' is not supported in LINQ to Entities. Only initializers, entity members, and entity navigation properties are supported

Question

I am trying to execute the following code and am receiving an error

public List GetLoggingData(DateTime LogDate, string title)
{
     var context          


        

Answer 1

Not the greatest solution, but it works. For a variety of reasons, I have to use .net 3.5 at this point and modifying the database would be difficult. Anyways, here is a solution that works:

            var query = from t in context.Logs
                      where t.Title == title 
                      && t.Timestamp.Day == LogDate.Day
                      && t.Timestamp.Month == LogDate.Month
                      && t.Timestamp.Year == LogDate.Year
                      select t;

Not the most elegant solution, but it is effective.

Answer 2

EntityFunctions.TruncateTime(t.Timestamp) is obsolete from EF6.

Use below

DbFunctions.TruncateTime(t.Timestamp)

Answer 3

You can use this hack:

DateTime startDate = LogDate.Date;
DateTime endDate = LogDate.Date.AddDays(1);

var query = from t in context.Logs
            where t.Title == title 
                  && t.Timestamp >= startDate 
                  && t.Timestamp < endDate
            select t;

Answer 4

If you are using EF 6.0+, you can use DbFunctions.TruncateTime(DateTime?) :

var query =
    from t in context.Logs
    where t.Title == title 
    && DbFunctions.TruncateTime(t.Timestamp) == LogDate.Date
    select t;

Note: For earlier version of EF where DbFunctions isn't available, EntityFunctions.TruncateTime(DateTime?) can be used instead.

Answer 5

Always use EntityFunctions.TruncateTime() for both x.DateTimeStart and LogDate. such as :

var query = from t in context.Logs
              where t.Title == title 
              && EntityFunctions.TruncateTime(t.Timestamp) == EntityFunctions.TruncateTime(LogDate)
              select t;

Answer 6

Correct me if I'm wrong, but in mikemurf22's example, it would need to check each part of the date component, and potentially a lot more server processing?

Anyway, I stumbled across this problem, and this is my solution.

Assuming that you're going to be passing in the date component only, you can find the last minute of the day that you pass in, and use the where clause to define the range.

public List<Log> GetLoggingData(DateTime LogDate, string title)
{
    DateTime enddate = new DateTime(LogDate.Year, LogDate.Month, LogDate.Day, 23, 59, 59)

    var query = from t in context.Logs
                where t.Timestamp >= date
                where t.Timestamp <= enddate
                select t;

    return query.ToList();
}