EntityFramework default properties

Blog.cs

using System;

using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.ComponentModel;

namespace YourNamespace
{
    [Table("Blogs")]
    // We inherit the EntityBase class here (with Id, CreatedAt and UpdatedAt)
    public class Blog : EntityBase
    {

        [MaxLength(150)]
        [Required]
        public string Name { get; set; }
        
        [Required]
        [DataType(DataType.MultilineText)]
        public string Text { get; set;}
    }
}

BlogsDatabase.cs

using System;
using System.Linq;
using System.Data.Entity;

namespace YourNamespace
{
    public class BlogsDatabase : DbContext
    {
        public InternshipDatabase() : base("BlogsDB") { }
        public DbSet<Blog> Blogs { get; set; }

        // Lets override the default save changes, so we automaticaly change the UpdatedAt field.
        public override int SaveChanges()
        {
            foreach (var entry in ChangeTracker.Entries().Where(x => x.Entity.GetType().GetProperty("CreatedAt") != null))
            {
                if (entry.State == EntityState.Added)
                {
                    entry.Property("CreatedAt").CurrentValue = DateTime.Now;
                }
                else if (entry.State == EntityState.Modified)
                {
                    // Ignore the CreatedTime updates on Modified entities. 
                    entry.Property("CreatedAt").IsModified = false;
                }
                // Always set UpdatedAt. Assuming all entities having CreatedAt property
                // Also have UpdatedAt
                entry.Property("UpdatedAt").CurrentValue = DateTime.Now;
            }
            return base.SaveChanges();
        }
    }
}

EntityBase.cs

using System;
using System.ComponentModel.DataAnnotations;

namespace YourNamespace
{
    public class EntityBase
    {
        [Key]
        public Guid Id { get; set; } = Guid.NewGuid();
        public DateTime? CreatedAt { get; set; } = DateTime.Now;
        public DateTime? UpdatedAt { get; set; } = DateTime.Now;
    }
}