<ExtensionAttribute()>
Public Overloads Shared Function Count(Of T)( _
   ByVal source As IEntityQuery(Of T) _
) As Integer

Dim source As IEntityQuery(Of T)
Dim value As Integer
 
value = EntityQueryExtensions.Count(Of T)(source)

[ExtensionAttribute()]
public static int Count<T>( 
   IEntityQuery<T> source
)

[ExtensionAttribute()]
public:
static int Countgeneric<typename T>
( 
   IEntityQuery<T^>^ source
) 

var mgr1 = new DomainModelEntityManager();
var ct = mgr1.Customers.Where(c=> c.Country == "UK").Count();