Sample snippets of assign initial value for c# property = ICS course

MessageBase.cs

using System;
namespace ICS_project.DAL.Entities
{
    public abstract class MessageBase : EntityBase
    {
        // compiler generate for you code from MessageBase1.cs, and initialize property with default value
        public DateTime CreationDate { get; } = DateTime.Now;
        public string Content { get; set; }
        public UserEntity User { get; set; }
    }
}

MessageBase1.cs

using System;
namespace ICS_project.DAL.Entities
{
    public abstract class MessageBase : EntityBase
    {
        private DateTime dateTime = DateTime.Now
        // property can be set only from this scope (from method or ctor)
        public DateTime CreationDate
        {
            get => dateTime;
            private set => dateTime = value;
        }
        public string Content { get; set; }
        public UserEntity User { get; set; }       
    }
}
// this proeprty 

MessageBase2.cs

using System;
namespace ICS_project.DAL.Entities
{
    public abstract class MessageBase : EntityBase
    {
        // same behavior as previous sample = MessageBase1.cs
        protected MessageBase(){
            CreationDate = DateTime.Now;
        }
        public DateTime CreationDate { get; }
        public string Content { get; set; }
        public UserEntity User { get; set; }
    }
}