'timestamp with time zone' literal cannot be generated for Local DateTime

Question

I am using .Net 7 and Entity with a Postgres database. The database provider is Npgsql.EntityFrameworkCore.PostgreSQL.

I am trying to seed some data that includes a UTC timestamp into my database. It is throwing the error:

Applying migration '20231016121421_AddData'.
    System.InvalidCastException: 'timestamp with time zone' literal cannot be generated for Local DateTime: a UTC DateTime is required
           at Npgsql.EntityFrameworkCore.PostgreSQL.Storage.Internal.Mapping.NpgsqlTimestampTzTypeMapping.GenerateLiteralCore(Object value)
           ...
    'timestamp with time zone' literal cannot be generated for Local DateTime: a UTC DateTime is required

Here is my code, I have played about with different UTC formats but I just can't find the right match.

public class AppDbContext: DbContext
    {

        public AppDbContext(DbContextOptions options) : base(options)
        {
        }

        // Database Tables
        public DbSet<DataTable> DataTable { get; set; }


        // Seed Database With Test Data
        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            base.OnModelCreating(modelBuilder);
            new DbInitializer(modelBuilder).Seed();
        }

    }

I think the error is the format of my UTC when I try to seed the database?

public class DbInitializer
    {
        private readonly ModelBuilder modelBuilder;

        public DbInitializer(ModelBuilder modelBuilder)
        {
            this.modelBuilder = modelBuilder;
        }

        // Starter Data For the Test Database
        public void Seed()
        {
            var dataJson = JsonConvert.DeserializeObject<List<DataTable>>(File.ReadAllText(@".\Database\Seed_Data.json"));
            modelBuilder.Entity<DataTable>().HasData(dataJson);
        }
    }

Sample json data, with the UTC timestamps:

[
  {
    "Id": "1f5ar5ty-6cc2-4054-b64e-bbc0dde5fg7b",
    "OrderDate": "2021-08-07T14:41:12.000000Z",
    "Product": "Apples",
  },
  {
    "Id": "ca5t10c0-756c-4b29-b16c-1389eb25b3a4",
    "OrderDate": "2021-08-07T14:41:12.000000Z",
    "Product": "Bananas"
  },
]

Any help appreciated!

Answer 1

Would something like this be of use? (Been a while since I touched C#.)

class OrderData
{
    public int Id { get; set; }
    public string OrderDate { get; set; }
    public string Product { get; set; }
}

class DataTable
{
    public int Id { get; set; }
    public DateTime OrderDate { get; set; }
    public string Product { get; set; }
}
class Program
{
    static void Main(string[] args)
    {
        var orders = JsonConvert.DeserializeObject<List<OrderData>>(File.ReadAllText(@".\seed.json"));
        var shapedOrders = orders.Select<DataTable>((order) =>
        {
            Id = order.Id;
            OrderDate = DateTime.SpecifyKind(DateTime.Parse(order.OrderDate), DateTimeKind.Utc);
            Product = order.Product;
        });
       

        new modelBuilder.Entity<DataTable>().HasData(shapedOrders);
    }
}