Question

I have a Domain object called User and UserCreateViewModel.Automapper is used for mapping from ViewModel to User.
Everything is working fine. When mapping is done I see User domain object has values in UserId, CreatedOn and ModifiedOn respectively like

00000000-0000-0000-0000-000000000000
1/1/0001 12:00:00 AM
1/1/0001 12:00:00 AM

These are default values when I instainciate User Object. This cause problem as my User object can not create Guid and Dates from properties Get.

Note: I don’t want to hardcode above default values.

Is there a clean approach to solve this problem so that UserId, CreateOn and ModifedOn generated values from properties?

I you understand my problem

UserCreateViewModel

public class UserCreateViewModel
{
    public string UserName { get; set; }
    public string Password { get; set; }
}

User

private Guid? _guid;
public Guid? UserId
{
    get
    {
        return (_guid.HasValue) ? _guid.Value : Guid.NewGuid();
    }
    set
    {
        _guid = value;
    }
}

public string UserName { get; set; }
public string Password { get; set; }

private DateTime? _createdOn;
public DateTime? CreatedOn
{
    get
    {
        return (_createdOn.HasValue) ? _createdOn.Value : DateTime.Now;
    }
    set
    {
        _createdOn = value;
    }
}

private DateTime? _modifiedOn;
public DateTime? ModifiedOn
{
    get
    {
        return (_modifiedOn.HasValue) ? _modifiedOn.Value : DateTime.Now;
    }
    set
    {
        _modifiedOn = value;
    }
}

Answer 1

Have a look at the BeforeMap and AfterMap features of Automapper. These might help you in customizing the assignment of default values.