Nullable datetime value
===

Can DateTime value be NULL? 

I have this code:

From here I inherit my variable 

    namespace Transakcija
    {
         public partial class Line
         {
            [System.Xml.Serialization.XmlElementAttribute(DataType = "date")]
            public System.DateTime DateOfProduction
            {
                get
                {
                    return this.dateOfProductionField;
                }
                set
                {
                    this.dateOfProductionField = value;
                }
            }
         }
    }

 Then for each loop:
 

     foreach (DataRow rw_det in dt_stavke.Rows)
      {
         List<Transakcija.Line> list = new List<Transakcija.Line>();
         Transakcija.Line l = new Transakcija.Line();
         
         //DateOfProduction
                                if (rw_det["DPRO02"].ToString().Length <= 0)
                                {
                                    
                                    l.DateOfProduction = default(DateTime);
    
                                }
                                else
                                {
                                    l.DateOfProduction = new DateTime();
                                    prod_date = rw_det["DPRO02"].ToString();
                                    DateTime pro_date = DateTime.ParseExact(prod_date, "dd.MM.yyyy", CultureInfo.InvariantCulture);
                                    string p_date = pro_date.ToString("yyyy-MM-dd");
                                    l.DateOfProduction = DateTime.Parse(p_date);
    
                                }
         
         
      }

  So the value l.DateOfProduction needs to be null, I have tried this:

  DateTime? dt = null;
  l.DateOfProduction = (DateTime)dt;

  But I got error: nullable object must have a value 

  So is this possible or I have to pass min value to variable?

  Thanks! 
  