Should I worry about UI in my domain? Domain Driven Design

Question

So I've been learning DDD and am attempting to refactor an old project using this approach. It is a fairly small app to register employees for events. These employees are initially populated from the DB, registered, and saved.

One business rule says that if an employee is marked as CannotAttend = true and they show up, then they are registered normally and CannotAttend is set to false.

My question involves the concern of the UI. A message, ReceivedMsg, is displayed based on the state the object is in when they are registering/attempting to register. The state would be initially set when the object is populated from the DB, and then when they register a different message is displayed based on if they had been marked as CannotAttend or not. This message is not stored in the DB.

Is this a problem the domain should be concerned about, or should I track these changes elsewhere?

Some example messages are:

Known when populated from DB - Not Currenty Registered, Already Registered

After registering - Registered, Registered and set to attend event

The UI displays this message and a color based on the initial state from the DB and then changed once the properties Registered and/or CannotAttend have changed.

public class Employee
{
    //DB properties
    public int EmployeeId { get; private set; }
    public string FirstName { get; private set; }
    public string LastName { get; private set; }
    public int BadgeId { get; private set; }
    public bool Registered { get; private set; }
    public int Swipes { get; private set; }
    public bool CannotAttend { get; private set; }

    //Not persisted
    public string ReceivedMsg { get; set; }
    public RegistrationType RegistrationType { get; private set;}


    public void Register(RegistrationType registrationType)
    {            
        if (!Registered)
        {
            Registered = true;
            Swipes = 0;                
        }

        if(CannotAttend)
        {
            CannotAttend = false;               
        }

        if (registrationType == RegistrationType.Badge) Swipes++;

    }      
}

Answer 1

Your Employee class contains logic that it is not concerned with. The Register method should not be part of the Employee object. Employees do not register themselves, they are submitted for Registration via an abstracted function.

What you are saying is the same as a McDonalds customer creating their own BigMac meal when actually the Kitchen does that for them.

You need to separate the Registration functions away, say into a Registration class that can be adapted to handle all sorts of Registrations.

Once this is done, your UI problem will go away.

Edit: Additionally, your Registration class would keep track of registered Employees, your employee does not need to do that.