C# LINQ replacing nulls with meaningful string

Question

From the list

class Delivery
{
    public string ProductCode
    {
        get;
        set;
    }

    public DateTime? OrderedDate
    {
        get;
        set;
    }

    public DateTime? DeliveryDate
    {
        get;
        set;
    }

    public Delivery(string pcode, DateTime? orddate, DateTime? deldate)
    {
        ProductCode = pcode;
        OrderedDate = orddate;
        DeliveryDate = deldate;
    }
}


List<Delivery> DeliveryList = new List<Delivery>();
DeliveryList.Add(new Delivery("P001",new DateTime(2009,01,27),null));
DeliveryList.Add(new Delivery("P007",new DateTime(2009,05,17),null));
DeliveryList.Add(new Delivery("P031", new DateTime(2008, 03, 15),
new DateTime(2008,04 ,22)));
DeliveryList.Add(new Delivery("P011",new DateTime(2009,01,27),
new DateTime(2009,02,12)));
DeliveryList.Add(new Delivery("P041",new DateTime(2009,01,27),null));
DeliveryList.Add(new Delivery("P051", new DateTime(2009, 01, 27),
new DateTime(2009, 02, 12)));
DeliveryList.Add(new Delivery("P501",new DateTime(2009,01,27),null));
DeliveryList.Add(new Delivery("P801",new DateTime(2009,01,27),null));

var query = DeliveryList.OrderBy(p => p.DeliveryDate);

For Report purpose ,During LINQ execution,What is the way to replace null values (Based on Delivery Date) with message "Yet to be delivered" (DateTime is value type).

Answer 1

var result = DeliveryList.Select(x => new
{
    ProductCode = x.ProductCode,
    OrderedDate = x.OrderedDate,
    DeliveryDate = x.DeliveryDate.HasValue 
        ? x.DeliveryDate.Value.ToString() : "Yet to be delivered"
}).OrderBy(p => p.DeliveryDate).ToArray();

Answer 2

I'm not 100% sure what your asking but it sounds like you want to convert DeliverList into a collection of strings indicating when they were delivered. In the case of a null DeliveryDate though you want the string "Yet to be delivered". If so try the following.

var dates = DeliveryList
  .Select(x => x.DeliverDate 
     ? x.DeliverDate.Value.ToString 
     : "Yet to be delivered");