How to compare only date components from DateTime in EF?

Question

I am having two date values, one already stored in the database and the other selected by the user using DatePicker. The use case is to search for a particular date from the

Answer 1

I think this could help you.

I made an extension since I have to compare dates in repositories filled with EF data and so .Date was not an option since it is not implemented in LinqToEntities translation.

Here is the code:

        /// <summary>
    /// Check if two dates are same
    /// </summary>
    /// <typeparam name="TElement">Type</typeparam>
    /// <param name="valueSelector">date field</param>
    /// <param name="value">date compared</param>
    /// <returns>bool</returns>
    public Expression<Func<TElement, bool>> IsSameDate<TElement>(Expression<Func<TElement, DateTime>> valueSelector, DateTime value)
    {
        ParameterExpression p = valueSelector.Parameters.Single();

        var antes = Expression.GreaterThanOrEqual(valueSelector.Body, Expression.Constant(value.Date, typeof(DateTime)));

        var despues = Expression.LessThan(valueSelector.Body, Expression.Constant(value.AddDays(1).Date, typeof(DateTime)));

        Expression body = Expression.And(antes, despues);

        return Expression.Lambda<Func<TElement, bool>>(body, p);
    }

then you can use it in this way.

 var today = DateTime.Now;
 var todayPosts = from t in turnos.Where(IsSameDate<Turno>(t => t.MyDate, today))
                                      select t);

Answer 2

Use the class EntityFunctions for trimming the time portion.

using System.Data.Objects;    

var bla = (from log in context.Contacts
           where EntityFunctions.TruncateTime(log.ModifiedDate) ==  EntityFunctions.TruncateTime(today.Date)
           select log).FirstOrDefault();

Source: http://social.msdn.microsoft.com/Forums/en-US/csharpgeneral/thread/84d4e18b-7545-419b-9826-53ff1a0e2a62/

UPDATE

As of EF 6.0 and later EntityFunctions is replaced by DbFunctions.

Answer 3

You can also use this:

DbFunctions.DiffDays(date1, date2) == 0

Answer 4

you can use DbFunctions.TruncateTime() method for this.

e => DbFunctions.TruncateTime(e.FirstDate.Value) == DbFunctions.TruncateTime(SecondDate);

Answer 5

This is how I do this.

DateTime date_time_to_compare = DateTime.Now;
//Compare only date parts
context.YourObject.FirstOrDefault(r =>
                EntityFunctions.TruncateTime(r.date) == EntityFunctions.TruncateTime(date_to_compare));

Answer 6

You can user below link to compare 2 dates without time :

private bool DateGreaterOrEqual(DateTime dt1, DateTime dt2)
        {
            return DateTime.Compare(dt1.Date, dt2.Date) >= 0;
        }

private bool DateLessOrEqual(DateTime dt1, DateTime dt2)
        {
            return DateTime.Compare(dt1.Date, dt2.Date) <= 0;
        }

the Compare function return 3 different values: -1 0 1 which means dt1>dt2, dt1=dt2, dt1