Replacing empty values with a default value in a Linq to Entities query - linq

Question

In the Linq to Entities query below I need to place a default value in the x.Number in the returned value if the query returns 0 OfficeTelephone objects. I have tried
x.Number??"555-1212" but that throws an error.
from c in Contacts
.Where(a => a.LastName.Contains("ANDUS")).Take(10)
select new
{
Id = c.Id,
OfficeTelephone = c.Telephones.Where(a=>a.TelephoneType.Name.Contains("Office")).Select(x => new { x.AreaCode, x.Number, x.TelephoneType, x.Primary })
}
I've tried something like:
from c in Contacts
.Where(a => a.LastName.Contains("ANDUS")).Take(10)
select new
{
Id = c.Id,
OfficeTelephone = c.Telephones
.Where(a=>a.TelephoneType.Name.Contains("Office"))
.Select(x => new { x.AreaCode, x.Number, x.TelephoneType, x.Primary })
.DefaultIfEmpty()}
But I'm not sure how to push a default object into the DefaultIFEmpty()

Answer 1

Use DefaultIfEmpty and pass a default instance with those value which you would want by default i.e. if no rows are returned.
try it like this:
Contacts.Where(a=>a.LastName.Contains("ANDUS"))
.Take(10)
.Select(x => new
{
Id = x.Id,
OfficeTelephone = x.Telephones
.Where(a=> a.Telephone.Name.Contains("Office"))
.Select(b=> new Telephone
{
b.AreaCode,
b.Number,
b.TelephoneType,
b.Primary
})
.DefaultIfEmpty(new Telephone())
});
where I've assumed that typeof(x.Telephones) == typeof(List<Telephone>)