Queryable.CountBy<TSource,TKey> 方法

定义

命名空间:

System.Linq

程序集:

System.Linq.Queryable.dll

Source:

Queryable.cs

public static System.Linq.IQueryable<System.Collections.Generic.KeyValuePair<TKey,int>> CountBy<TSource,TKey> (this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,TKey>> keySelector, System.Collections.Generic.IEqualityComparer<TKey>? comparer = default);

static member CountBy : System.Linq.IQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, 'Key>> * System.Collections.Generic.IEqualityComparer<'Key> -> System.Linq.IQueryable<System.Collections.Generic.KeyValuePair<'Key, int>>

<Extension()>
Public Function CountBy(Of TSource, TKey) (source As IQueryable(Of TSource), keySelector As Expression(Of Func(Of TSource, TKey)), Optional comparer As IEqualityComparer(Of TKey) = Nothing) As IQueryable(Of KeyValuePair(Of TKey, Integer))

类型参数

TSource

TKey

参数

source

IQueryable<TSource>

keySelector

Expression<Func<TSource,TKey>>

comparer

IEqualityComparer<TKey>

返回

IQueryable<KeyValuePair<TKey,Int32>>