LINQ series: LINQ to object grouping operators

Grouping refers to grouping values or elements in a sequence based on a specific value. LINQ only contains one grouping OPERATOR: groupby.

Groupby

1>. Prototype Definition

Public static iqueryable <igrouping <tkey, tsource> groupby <tsource, tkey> (this iqueryable <tsource> source, expression <func <tsource, tkey> keyselector );

2>. Example

VaR expr = from P in context. products Group P by P. categoryid; foreach (VAR item in expr) {foreach (var p in item) {console. writeline (P. productname );}}

VaR expr = context. Cities. groupby (C => C. provinceid );

LINQ series: LINQ to object grouping operators