Default property values in MVC3

Question

I have 2 classes containg POCO entities in MVC3

public class TeamMember 
{
  public DateTime JoinDate { get; set; }
  [Required]
  Public string Name{ get; set; }
} 

public class Project
{
   [Required]
   public string Name { get; set; }  
   public DateTime StartDate { get; set; }
}

I want to set the default value of TeamMember JoinDate with Project StartDate. Can anybody pull me out of this

Answer 1

You could do it in the controller, something like:

if(teamMember.JoinDate == null)
{
    teamMember.JoinDate = project.StartDate;
}

and you could add more logic if project.StartDate == null then project.StartDate = DateTime.Now.

I'm not sure you can do this as a default in the model itself though.

Update

As you have it, I don't think the Project StartDate can see the TeamMember JoinDate, I think you will need to give them a one to one relationship. I'm not sure of the exact syntax since I'm not on my work system, but something like this should work:

    public class TeamMember 
    {
      public DateTime JoinDate
      { 
          get { return this.JoinDate; }
          set { JoinDate = this.Project.StartDate; }
      }
      [Required]
      public string Name{ get; set; }
      public virtual Project Project { get; set; }
    } 

    public class Project
    {
       [Required]
       public string Name { get; set; }  
       public DateTime StartDate { get; set; }
    }

Update 2

Thinking about it, you need to allow JoinDate to be null or else it will throw a validation error, then you need to check to see if there is a value for it. Something more like this:

    public class TeamMember 
    {
      public DateTime? JoinDate
      { 
          get { return this.JoinDate; }
          set
          {
              if(JoinDate == null)
              {
                  JoinDate = this.Project.StartDate;
              }
              else
              {
                  JoinDate = JoinDate;
              }
          }
      }
      [Required]
      public string Name{ get; set; }
      public virtual Project Project { get; set; }
    }

Answer 2

Sounds like you need a custom model binder for the TeamMember class. This of course assumes that you have access to project.StartDate when TeamMember is being created.

Answer 3

I have used [DefaultValue()] for bool, int, string data type. Try it for DateTime, I am not sure but giving you just workaround.