C# 0 The Complete Reference

PART I

C h a p t e r   1 9 :  

L I N Q  

577

PART IPART I

var inStockList = from item in items

                  join entry in statusList

                    on item.ItemNumber equals entry.ItemNumber

                  select new Temp(item.Name, entry.InStock);

This query produces a sequence that contains objects that encapsulate the name and the in-

stock status of an inventory item. This information is synthesized from joining the two lists 

items

 and 

statusList

. The following version reworks this query so that it uses the 

Join( )

method rather than the C# query syntax:

// Use Join() to produce a list of item names and status.

var inStockList = items.Join(statusList,

                    k1 => k1.ItemNumber,

                    k2 => k2.ItemNumber,

                    (k1, k2) => new Temp(k1.Name, k2.InStock) );

Although this version uses the named class called 

Temp

 to hold the resulting object, an 

anonymous type could have been used instead. This approach is shown next:

var inStockList = items.Join(statusList,

                    k1 => k1.ItemNumber,

                    k2 => k2.ItemNumber,

                    (k1, k2) => new { k1.Name, k2.InStock} );