Date Only cannot be mapped SQL Server 2019

Question

I am trying to use the new DateOnly aspects of c# but when I come to do my migrations I am having the following issue. I am using SQL Server 2019 the error is.

'Amenitie.StartDate could not be mapped because it is of type 'DateOnly', which is not a supported primitive type or a valid entity type. Either explicitly map this property, or ignore it using the'

My model is as follows

public class Amenitie
{
    public int? Id { get; set; }
    public Rooms? Rooms { get; set; }
    public string? Description { get; set; }
    public DateOnly StartDate { get; set; }
    public DateOnly EndDate { get; set; }
    public bool? isAvailable { get; set; }
    public bool? isDeleted { get; set; }
    public bool? isActive { get; set; }
    public DateTime? LastModifiedBy { get; set; }
    public DateTime? CreateDate { get; set; }
}

My Dal project and my web project are both set to


  net6.0
  enable

I am using the following package versions.


 
 
 
 
 all
 runtime; build; native; contentfiles; analyzers; buildtransitive
 
 
 
 
 
  all
  runtime; build; native; contentfiles; analyzers; buildtransitive

Is DateOnly available in EF Core 6 and above I presume?

user_10366337 · Answer

Try this

      public class YourDbContext : DbContext
      {
            Ctors() {...}

        protected override void ConfigureConventions(ModelConfigurationBuilder builder)
        {
            builder.Properties()
                .HaveConversion()
                .HaveColumnType("date");
        }
      }
              
      /// 
      /// Converts  to  and vice versa.
      /// 
      public class DateOnlyConverter : ValueConverter
      {
          /// 
          /// Creates a new instance of this converter.
          /// 
          public DateOnlyConverter() : base(
                  d => d.ToDateTime(TimeOnly.MinValue),
                  d => DateOnly.FromDateTime(d))
          { }
      }

EDIT: with RC2 this does not work for nullable types.

EDIT 2: with NET6 release version this works for nullable types again, and more than that, you dont need to have a separate converter for "DateOnly?" anymore.

user_72563 · Answer

You have two choices:

use DateTime instead of DateOnly.
build a custom converter (see below).

As far I can see, the actual version of Entity Framework Core issue tracker states that model builder does not support it (find the issue here). Building a converter may solve your issue (cited from there):

protected override void ConfigureConventions(ModelConfigurationBuilder builder)
{
   builder.Properties()
          .HaveConversion()
          .HaveColumnType("date");
}

Date Only cannot be mapped SQL Server 2019

2 Answers