GroupBy<TSource,TKey,TElement,TResult>(IEntityQuery<TSource>,Expression<Func<TSource,TKey>>,Expression<Func<TSource,TElement>>,Expression<Func<TKey,IEnumerable<TElement>,TResult>>) Method

Groups the elements of a sequence according to a specified key selector function and creates a result value from each group and its key. The elements of each group are projected by using a specified function.

Syntax

Visual Basic
C#

'Declaration
 
<ExtensionAttribute()>
Public Overloads Shared Function GroupBy
    (Of TSource,TKey,TElement,TResult)( _
   ByVal source As IEntityQuery(Of TSource), _
   ByVal keySelector As Expression(Of Func(Of TSource,TKey)), _
   ByVal elementSelector As Expression(Of Func(Of TSource,TElement)), _
   ByVal resultSelector As Expression(Of Func(Of TKey,IEnumerable(Of TElement),TResult)) _
) As IEntityQuery(Of TResult)

'Usage
 
Dim source As IEntityQuery(Of TSource)
Dim keySelector As Expression(Of Func(Of TSource,TKey))
Dim elementSelector As Expression(Of Func(Of TSource,TElement))
Dim resultSelector As Expression(Of Func(Of TKey,IEnumerable(Of TElement),TResult))
Dim value As IEntityQuery(Of TResult)
 
value = EntityQueryExtensions.GroupBy(Of TSource, TKey, TElement, TResult)(source, keySelector, elementSelector, resultSelector)

[Extension()]
public static IEntityQuery<TResult> GroupBy<TSource,TKey,TElement,TResult>( 
   IEntityQuery<TSource> source,
   Expression<Func<TSource,TKey>> keySelector,
   Expression<Func<TSource,TElement>> elementSelector,
   Expression<Func<TKey,IEnumerable<TElement>,TResult>> resultSelector
)

Parameters

source
keySelector
elementSelector
resultSelector

Type Parameters

TSource
TKey
TElement
TResult

Example

var mgr = new DomainModelEntityManager();

var query = mgr.Customers.GroupBy(c => c.Country, c => c.CompanyName, (s, a) => new { Key = s, Count = a.Count() });
  //(s, c) => new { Key=s, Count=c.Count()});
foreach (var group in query) {
  Console.WriteLine("key = " + group.Key);
  Console.WriteLine("count=" + group.Count);
}

Requirements

Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference

EntityQueryExtensions Class
EntityQueryExtensions Members
Overload List