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支持和不支持的 LINQ 方法 (LINQ to Entities)

  • 项目

本节提供有关 LINQ to Entities 查询中支持和不支持的语言集成查询 (LINQ) 标准查询运算符的信息。 许多 LINQ 标准查询运算符都有可接受整数参数的重载版本。 该整数参数对应于正在操作的序列中从零开始的索引，IEqualityComparer 或 IComparer。 除非专门指定，否则这些 LINQ 标准查询运算符的重载版本并不受支持，尝试使用它们将引发异常。

投影和限制方法

LINQ to Entities 查询中支持大多数 LINQ 投影和限制方法，除了那些接受位置参数的方法。 有关更多信息，请参见 LINQ to Entities 查询中的标准查询运算符。 下表列出了支持的和不支持的投影和限制方法。

方法 支持 Visual Basic 函数签名 C# 方法签名

Select

支持

 
Function Select(Of TSource, TResult) ( _
source As IQueryable(Of TSource), _
selector As Expression(Of Func(Of TSource, TResult)) _
) As IQueryable(Of TResult)
 
IQueryable<TResult> Select<TSource, TResult>(
this IQueryable<TSource> source,
Expression<Func<TSource, TResult>> selector
)

Select

不支持

 
Function Select(Of TSource, TResult) ( _
source As IQueryable(Of TSource), _
selector As Expression(Of Func(Of TSource, Integer, TResult)) _
) As IQueryable(Of TResult)
 
IQueryable<TResult> Select<TSource, TResult>(
this IQueryable<TSource> source,
Expression<Func<TSource, int, TResult>> selector
)

SelectMany

支持

 
Function SelectMany(Of TSource, TResult) ( _
source As IQueryable(Of TSource), _
selector As Expression(Of Func(Of TSource, IEnumerable(Of TResult))) _
) As IQueryable(Of TResult)
 
IQueryable<TResult> SelectMany<TSource, TResult>(
this IQueryable<TSource> source,
Expression<Func<TSource, IEnumerable<TResult>>> selector
)

SelectMany

不支持

 
Function SelectMany(Of TSource, TResult) ( _
source As IQueryable(Of TSource), _
selector As Expression(Of Func(Of TSource, Integer, IEnumerable(Of TResult))) _
) As IQueryable(Of TResult)
 
IQueryable<TResult> SelectMany<TSource, TResult>(
this IQueryable<TSource> source,
Expression<Func<TSource, int, IEnumerable<TResult>>> selector
)

SelectMany

支持

 
Function SelectMany(Of TSource, TCollection, TResult) ( _
source As IQueryable(Of TSource), _
collectionSelector As Expression(Of Func(Of TSource, IEnumerable(Of TCollection))), _
resultSelector As Expression(Of Func(Of TSource, TCollection, TResult)) _
) As IQueryable(Of TResult)
 
IQueryable<TResult> SelectMany<TSource, TCollection, TResult>(
this IQueryable<TSource> source,
Expression<Func<TSource, IEnumerable<TCollection>>> collectionSelector,
Expression<Func<TSource, TCollection, TResult>> resultSelector
)

SelectMany

不支持

 
Function SelectMany(Of TSource, TCollection, TResult) ( _
source As IQueryable(Of TSource), _
collectionSelector As Expression(Of Func(Of TSource, Integer, IEnumerable(Of TCollection))), _
resultSelector As Expression(Of Func(Of TSource, TCollection, TResult)) _
) As IQueryable(Of TResult)
 
IQueryable<TResult> SelectMany<TSource, TCollection, TResult>(
this IQueryable<TSource> source,
Expression<Func<TSource, int, IEnumerable<TCollection>>> collectionSelector,
Expression<Func<TSource, TCollection, TResult>> resultSelector
)

Where

支持

 
Function Where(Of TSource) ( _
source As IQueryable(Of TSource), _
predicate As Expression(Of Func(Of TSource, Boolean)) _
) As IQueryable(Of TSource)
 
IQueryable<TSource> Where<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, bool>> predicate
)

Where

不支持

 
Function Where(Of TSource) ( _
source As IQueryable(Of TSource), _
predicate As Expression(Of Func(Of TSource, Integer, Boolean)) _
) As IQueryable(Of TSource)
 
IQueryable<TSource> Where<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, int, bool>> predicate
)

联接方法

LINQ to Entities 支持 LINQ 联接方法，但不支持接受 IEqualityComparer 的联接方法，原因是比较器不能转换为数据源。 有关更多信息，请参见 LINQ to Entities 查询中的标准查询运算符。 下表列出了支持的和不支持的联接方法。

方法 支持 Visual Basic 函数签名 C# 方法签名

GroupJoin

支持

 
Function GroupJoin(Of TOuter, TInner, TKey, TResult) ( _
outer As IQueryable(Of TOuter), _
inner As IEnumerable(Of TInner), _
outerKeySelector As Expression(Of Func(Of TOuter, TKey)), _
innerKeySelector As Expression(Of Func(Of TInner, TKey)), _
resultSelector As Expression(Of Func(Of TOuter, IEnumerable(Of TInner), TResult)) _
) As IQueryable(Of TResult)
 
IQueryable<TResult> GroupJoin<TOuter, TInner, TKey, TResult>(
this IQueryable<TOuter> outer,
IEnumerable<TInner> inner,
Expression<Func<TOuter, TKey>> outerKeySelector,
Expression<Func<TInner, TKey>> innerKeySelector,
Expression<Func<TOuter, IEnumerable<TInner>, TResult>> resultSelector
)

GroupJoin

不支持

 
Function GroupJoin(Of TOuter, TInner, TKey, TResult) ( _
outer As IQueryable(Of TOuter), _
inner As IEnumerable(Of TInner), _
outerKeySelector As Expression(Of Func(Of TOuter, TKey)), _
innerKeySelector As Expression(Of Func(Of TInner, TKey)), _
resultSelector As Expression(Of Func(Of TOuter, IEnumerable(Of TInner), TResult)), _
comparer As IEqualityComparer(Of TKey) _
) As IQueryable(Of TResult)
 
IQueryable<TResult> GroupJoin<TOuter, TInner, TKey, TResult>(
this IQueryable<TOuter> outer,
IEnumerable<TInner> inner,
Expression<Func<TOuter, TKey>> outerKeySelector,
Expression<Func<TInner, TKey>> innerKeySelector,
Expression<Func<TOuter, IEnumerable<TInner>, TResult>> resultSelector,
IEqualityComparer<TKey> comparer
)

Join

支持

 
Function Join(Of TOuter, TInner, TKey, TResult) ( _
outer As IQueryable(Of TOuter), _
inner As IEnumerable(Of TInner), _
outerKeySelector As Expression(Of Func(Of TOuter, TKey)), _
innerKeySelector As Expression(Of Func(Of TInner, TKey)), _
resultSelector As Expression(Of Func(Of TOuter, TInner, TResult)) _
) As IQueryable(Of TResult)
 
IQueryable<TResult> Join<TOuter, TInner, TKey, TResult>(
this IQueryable<TOuter> outer,
IEnumerable<TInner> inner,
Expression<Func<TOuter, TKey>> outerKeySelector,
Expression<Func<TInner, TKey>> innerKeySelector,
Expression<Func<TOuter, TInner, TResult>> resultSelector
)

Join

不支持

 
 Function Join(Of TOuter, TInner, TKey, TResult) ( _
outer As IQueryable(Of TOuter), _
inner As IEnumerable(Of TInner), _
outerKeySelector As Expression(Of Func(Of TOuter, TKey)), _
innerKeySelector As Expression(Of Func(Of TInner, TKey)), _
resultSelector As Expression(Of Func(Of TOuter, TInner, TResult)), _
comparer As IEqualityComparer(Of TKey) _
) As IQueryable(Of TResult)
 
IQueryable<TResult> Join<TOuter, TInner, TKey, TResult>(
this IQueryable<TOuter> outer,
IEnumerable<TInner> inner,
Expression<Func<TOuter, TKey>> outerKeySelector,
Expression<Func<TInner, TKey>> innerKeySelector,
Expression<Func<TOuter, TInner, TResult>> resultSelector,
IEqualityComparer<TKey> comparer
)

集方法

LINQ to Entities 查询中支持大多数 LINQ 集方法，但使用 EqualityComparer 的那些方法除外。 有关更多信息，请参见 LINQ to Entities 查询中的标准查询运算符。 下表列出了支持的和不支持的集方法。

方法 支持 Visual Basic 函数签名 C# 方法签名

All

支持

 
Function All(Of TSource) ( _
source As IQueryable(Of TSource), _
predicate As Expression(Of Func(Of TSource, Boolean)) _
) As Boolean
 
bool All<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, bool>> predicate
)

Any

支持

 
Function Any(Of TSource) ( _
source As IQueryable(Of TSource) _
) As Boolean
 
bool Any<TSource>(
this IQueryable<TSource> source
)

Any

支持

 
Function Any(Of TSource) ( _
source As IQueryable(Of TSource), _
predicate As Expression(Of Func(Of TSource, Boolean)) _
) As Boolean
 
bool Any<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, bool>> predicate
)

Contains

支持

 
Function Contains(Of TSource) ( _
source As IQueryable(Of TSource), _
item As TSource _
) As Boolean
 
bool Contains<TSource>(
this IQueryable<TSource> source,
TSource item
)

Contains

不支持

 
Function Contains(Of TSource) ( _
source As IQueryable(Of TSource), _
item As TSource, _
comparer As IEqualityComparer(Of TSource) _
) As Boolean
 
bool Contains<TSource>(
this IQueryable<TSource> source,
TSource item,
IEqualityComparer<TSource> comparer
)

Concat

支持，但不保证

保留顺序

 
Function Concat(Of TSource) ( _
source1 As IQueryable(Of TSource), _
source2 As IEnumerable(Of TSource) _
) As IQueryable(Of TSource)
 
IQueryable<TSource> Concat<TSource>(
this IQueryable<TSource> source1,
IEnumerable<TSource> source2
)

DefaultIfEmpty

支持

 
Function DefaultIfEmpty(Of TSource) ( _
source As IQueryable(Of TSource) _
) As IQueryable(Of TSource)
 
IQueryable<TSource> DefaultIfEmpty<TSource>(
this IQueryable<TSource> source
)

DefaultIfEmpty

支持

 
Function DefaultIfEmpty(Of TSource) ( _
source As IQueryable(Of TSource), _
defaultValue As TSource _
) As IQueryable(Of TSource)
 
IQueryable<TSource> DefaultIfEmpty<TSource>(
this IQueryable<TSource> source,
TSource defaultValue
)

Distinct

支持

 
Function Distinct(Of TSource) ( _
source As IQueryable(Of TSource) _
) As IQueryable(Of TSource)
 
IQueryable<TSource> Distinct<TSource>(
this IQueryable<TSource> source
)

Distinct

不支持

 
Function Distinct(Of TSource) ( _
source As IQueryable(Of TSource), _
comparer As IEqualityComparer(Of TSource) _
) As IQueryable(Of TSource)
 
IQueryable<TSource> Distinct<TSource>(
this IQueryable<TSource> source,
IEqualityComparer<TSource> comparer
)

Except

支持

 
Function Except(Of TSource) ( _
source1 As IQueryable(Of TSource), _
source2 As IEnumerable(Of TSource) _
) As IQueryable(Of TSource)
 
IQueryable<TSource> Except<TSource>(
this IQueryable<TSource> source1,
IEnumerable<TSource> source2
)

Except

不支持

 
Function Except(Of TSource) ( _
source1 As IQueryable(Of TSource), _
source2 As IEnumerable(Of TSource), _
comparer As IEqualityComparer(Of TSource) _
) As IQueryable(Of TSource)
 
IQueryable<TSource> Except<TSource>(
this IQueryable<TSource> source1,
IEnumerable<TSource> source2,
IEqualityComparer<TSource> comparer
)

Intersect

支持

 
Function Intersect(Of TSource) ( _
source1 As IQueryable(Of TSource), _
source2 As IEnumerable(Of TSource) _
) As IQueryable(Of TSource)
 
IQueryable<TSource> Intersect<TSource>(
this IQueryable<TSource> source1,
IEnumerable<TSource> source2
)

Intersect

不支持

 
Function Intersect(Of TSource) ( _
source1 As IQueryable(Of TSource), _
source2 As IEnumerable(Of TSource), _
comparer As IEqualityComparer(Of TSource) _
) As IQueryable(Of TSource)
 
IQueryable<TSource> Intersect<TSource>(
this IQueryable<TSource> source1,
IEnumerable<TSource> source2,
IEqualityComparer<TSource> comparer
)

Union

支持

 
Function Union(Of TSource) ( _
source1 As IQueryable(Of TSource), _
source2 As IEnumerable(Of TSource) _
) As IQueryable(Of TSource)
 
IQueryable<TSource> Union<TSource>(
this IQueryable<TSource> source1,
IEnumerable<TSource> source2
)

Union

不支持

 
Function Union(Of TSource) ( _
source1 As IQueryable(Of TSource), _
source2 As IEnumerable(Of TSource), _
comparer As IEqualityComparer(Of TSource) _
) As IQueryable(Of TSource)
 
IQueryable<TSource> Union<TSource>(
this IQueryable<TSource> source1,
IEnumerable<TSource> source2,
IEqualityComparer<TSource> comparer
)

排序方法

LINQ to Entities 支持大多数 LINQ 排序方法，但不支持接受 IComparer 的排序方法，原因是比较器不能转换为数据源。 有关更多信息，请参见 LINQ to Entities 查询中的标准查询运算符。 下表列出了支持的和不支持的排序方法。

方法 支持 Visual Basic 函数签名 C# 方法签名

OrderBy

支持

 
Function OrderBy(Of TSource, TKey) ( _
source As IQueryable(Of TSource), _
keySelector As Expression(Of Func(Of TSource, TKey)) _
) As IOrderedQueryable(Of TSource)
 
IOrderedQueryable<TSource> OrderBy<TSource, TKey>(
this IQueryable<TSource> source,
Expression<Func<TSource, TKey>> keySelector
)

OrderBy

不支持

 
Function OrderBy(Of TSource, TKey) ( _
source As IQueryable(Of TSource), _
keySelector As Expression(Of Func(Of TSource, TKey)), _
comparer As IComparer(Of TKey) _
) As IOrderedQueryable(Of TSource)
 
IOrderedQueryable<TSource> OrderBy<TSource, TKey>(
this IQueryable<TSource> source,
Expression<Func<TSource, TKey>> keySelector,
IComparer<TKey> comparer
)

OrderByDescending

支持

 
Function OrderByDescending(Of TSource, TKey) ( _
source As IQueryable(Of TSource), _
keySelector As Expression(Of Func(Of TSource, TKey)) _
) As IOrderedQueryable(Of TSource)
 
IOrderedQueryable<TSource> OrderByDescending<TSource, TKey>(
this IQueryable<TSource> source,
Expression<Func<TSource, TKey>> keySelector
)

OrderByDescending

不支持

 
Function OrderByDescending(Of TSource, TKey) ( _
source As IQueryable(Of TSource), _
keySelector As Expression(Of Func(Of TSource, TKey)), _
comparer As IComparer(Of TKey) _
) As IOrderedQueryable(Of TSource)
 
IOrderedQueryable<TSource> OrderByDescending<TSource, TKey>(
this IQueryable<TSource> source,
Expression<Func<TSource, TKey>> keySelector,
IComparer<TKey> comparer
)

ThenBy

支持

 
Function ThenBy(Of TSource, TKey) ( _
source As IOrderedQueryable(Of TSource), _
keySelector As Expression(Of Func(Of TSource, TKey)) _
) As IOrderedQueryable(Of TSource)
 
IOrderedQueryable<TSource> ThenBy<TSource, TKey>(
this IOrderedQueryable<TSource> source,
Expression<Func<TSource, TKey>> keySelector
)

ThenBy

不支持

 
Function ThenBy(Of TSource, TKey) ( _
source As IOrderedQueryable(Of TSource), _
keySelector As Expression(Of Func(Of TSource, TKey)), _
comparer As IComparer(Of TKey) _
) As IOrderedQueryable(Of TSource)
 
IOrderedQueryable<TSource> ThenBy<TSource, TKey>(
this IOrderedQueryable<TSource> source,
Expression<Func<TSource, TKey>> keySelector,
IComparer<TKey> comparer
)

ThenByDescending

支持

 
Function ThenByDescending(Of TSource, TKey) ( _
source As IOrderedQueryable(Of TSource), _
keySelector As Expression(Of Func(Of TSource, TKey)) _
) As IOrderedQueryable(Of TSource)
 
IOrderedQueryable<TSource> ThenByDescending<TSource, TKey>(
this IOrderedQueryable<TSource> source,
Expression<Func<TSource, TKey>> keySelector
)

ThenByDescending

不支持

 
Function ThenByDescending(Of TSource, TKey) ( _
source As IOrderedQueryable(Of TSource), _
keySelector As Expression(Of Func(Of TSource, TKey)), _
comparer As IComparer(Of TKey) _
) As IOrderedQueryable(Of TSource)
 
IOrderedQueryable<TSource> ThenByDescending<TSource, TKey>(
this IOrderedQueryable<TSource> source,
Expression<Func<TSource, TKey>> keySelector,
IComparer<TKey> comparer
)

Reverse

不支持

 
Function Reverse(Of TSource) ( _
source As IQueryable(Of TSource) _
) As IQueryable(Of TSource)
 
IQueryable<TSource> Reverse<TSource>(
this IQueryable<TSource> source
)

分组方法

LINQ to Entities 支持多数 LINQ 分组方法，但由于比较器不能转换为数据源，因此不支持接受 IEqualityComparer 的那些方法。 有关更多信息，请参见 LINQ to Entities 查询中的标准查询运算符。 下表列出了支持的和不支持的分组方法。

方法 支持 Visual Basic 函数签名 C# 方法签名

GroupBy

支持

 
Function GroupBy(Of TSource, TKey) ( _
source As IQueryable(Of TSource), _
keySelector As Expression(Of Func(Of TSource, TKey)) _
) As IQueryable(Of IGrouping(Of TKey, TSource))
 
IQueryable<IGrouping<TKey, TSource>> GroupBy<TSource, TKey>(
this IQueryable<TSource> source,
Expression<Func<TSource, TKey>> keySelector
)

GroupBy

不支持

 
Function GroupBy(Of TSource, TKey) ( _
source As IQueryable(Of TSource), _
keySelector As Expression(Of Func(Of TSource, TKey)), _
comparer As IEqualityComparer(Of TKey) _
) As IQueryable(Of IGrouping(Of TKey, TSource))
 
IQueryable<IGrouping<TKey, TSource>> GroupBy<TSource, TKey>(
this IQueryable<TSource> source,
Expression<Func<TSource, TKey>> keySelector,
IEqualityComparer<TKey> comparer
)

GroupBy

支持

 
Function GroupBy(Of TSource, TKey, TElement) ( _
source As IQueryable(Of TSource), _
keySelector As Expression(Of Func(Of TSource, TKey)), _
elementSelector As Expression(Of Func(Of TSource, TElement)) _
) As IQueryable(Of IGrouping(Of TKey, TElement))
 
IQueryable<IGrouping<TKey, TElement>> GroupBy<TSource, TKey, TElement>(
this IQueryable<TSource> source,
Expression<Func<TSource, TKey>> keySelector,
Expression<Func<TSource, TElement>> elementSelector
)

GroupBy

支持

 
Function GroupBy(Of TSource, TKey, TResult) ( _
source As IQueryable(Of TSource), _
keySelector As Expression(Of Func(Of TSource, TKey)), _
resultSelector As Expression(Of Func(Of TKey, IEnumerable(Of TSource), TResult)) _
) As IQueryable(Of TResult)
 
IQueryable<TResult> GroupBy<TSource, TKey, TResult>(
this IQueryable<TSource> source,
Expression<Func<TSource, TKey>> keySelector,
Expression<Func<TKey, IEnumerable<TSource>, TResult>> resultSelector
)

GroupBy

不支持

 
Function GroupBy(Of TSource, TKey, TElement) ( _
source As IQueryable(Of TSource), _
keySelector As Expression(Of Func(Of TSource, TKey)), _
elementSelector As Expression(Of Func(Of TSource, TElement)), _
comparer As IEqualityComparer(Of TKey) _
) As IQueryable(Of IGrouping(Of TKey, TElement))
 
IQueryable<IGrouping<TKey, TElement>> GroupBy<TSource, TKey, TElement>(
this IQueryable<TSource> source,
Expression<Func<TSource, TKey>> keySelector,
Expression<Func<TSource, TElement>> elementSelector,
IEqualityComparer<TKey> comparer

GroupBy

支持

 
Function GroupBy(Of TSource, TKey, TElement, TResult) ( _
source As IQueryable(Of TSource), _
keySelector As Expression(Of Func(Of TSource, TKey)), _
elementSelector As Expression(Of Func(Of TSource, TElement)), _
resultSelector As Expression(Of Func(Of TKey, IEnumerable(Of TElement), TResult)) _
) As IQueryable(Of TResult)
 
IQueryable<TResult> GroupBy<TSource, TKey, TElement, TResult>(
this IQueryable<TSource> source,
Expression<Func<TSource, TKey>> keySelector,
Expression<Func<TSource, TElement>> elementSelector,
Expression<Func<TKey, IEnumerable<TElement>, TResult>> resultSelector
)

GroupBy

不支持

 
Function GroupBy(Of TSource, TKey, TResult) ( _
source As IQueryable(Of TSource), _
keySelector As Expression(Of Func(Of TSource, TKey)), _
resultSelector As Expression(Of Func(Of TKey, IEnumerable(Of TSource), TResult)), _
comparer As IEqualityComparer(Of TKey) _
) As IQueryable(Of TResult)
 
IQueryable<TResult> GroupBy<TSource, TKey, TResult>(
this IQueryable<TSource> source,
Expression<Func<TSource, TKey>> keySelector,
Expression<Func<TKey, IEnumerable<TSource>, TResult>> resultSelector,
IEqualityComparer<TKey> comparer
)

GroupBy

不支持

 
Function GroupBy(Of TSource, TKey, TElement, TResult) ( _
source As IQueryable(Of TSource), _
keySelector As Expression(Of Func(Of TSource, TKey)), _
elementSelector As Expression(Of Func(Of TSource, TElement)), _
resultSelector As Expression(Of Func(Of TKey, IEnumerable(Of TElement), TResult)), _
comparer As IEqualityComparer(Of TKey) _
) As IQueryable(Of TResult)
 
IQueryable<TResult> GroupBy<TSource, TKey, TElement, TResult>(
this IQueryable<TSource> source,
Expression<Func<TSource, TKey>> keySelector,
Expression<Func<TSource, TElement>> elementSelector,
Expression<Func<TKey, IEnumerable<TElement>, TResult>> resultSelector,
IEqualityComparer<TKey> comparer
)

聚合方法

LINQ to Entities 中支持大多数接受基元数据类型的聚合方法。 有关更多信息，请参见 LINQ to Entities 查询中的标准查询运算符。 下表列出了支持的和不支持的聚合方法。

方法 支持 Visual Basic 函数签名 C# 方法签名

Aggregate

不支持

 
Function Aggregate(Of TSource) ( _
source As IQueryable(Of TSource), _
func As Expression(Of Func(Of TSource, TSource, TSource)) _
) As TSource
 
TSource Aggregate<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, TSource, TSource>> func
)

Aggregate

不支持

 
Function Aggregate(Of TSource, TAccumulate) ( _
source As IQueryable(Of TSource), _
seed As TAccumulate, _
func As Expression(Of Func(Of TAccumulate, TSource, TAccumulate)) _
) As TAccumulate
 
TAccumulate Aggregate<TSource, TAccumulate>(
this IQueryable<TSource> source,
TAccumulate seed,
Expression<Func<TAccumulate, TSource, TAccumulate>> func
)

Aggregate

不支持

 
Function Aggregate(Of TSource, TAccumulate, TResult) ( _
source As IQueryable(Of TSource), _
seed As TAccumulate, _
func As Expression(Of Func(Of TAccumulate, TSource, TAccumulate)), _
selector As Expression(Of Func(Of TAccumulate, TResult)) _
) As TResult
 
TResult Aggregate<TSource, TAccumulate, TResult>(
this IQueryable<TSource> source,
TAccumulate seed,
Expression<Func<TAccumulate, TSource, TAccumulate>> func,
Expression<Func<TAccumulate, TResult>> selector
)

Average

支持

 
Function Average ( _
source As IQueryable(Of Decimal) _
) As Decimal
 
decimal Average(
this IQueryable<decimal> source
)

Average

支持

 
Function Average ( _
source As IQueryable(Of Double) _
) As Double
 
double Average(
this IQueryable<double> source
)

Average

支持

 
Function Average ( _
source As IQueryable(Of Integer) _
) As Double
 
double Average(
this IQueryable<int> source
)

Average

支持

 
Function Average ( _
source As IQueryable(Of Long) _
) As Double
 
double Average(
this IQueryable<long> source
)

Average

支持

 
Function Average ( _
source As IQueryable(Of Nullable(Of Decimal)) _
) As Nullable(Of Decimal)
 
Nullable<decimal> Average(
this IQueryable<Nullable<decimal>> source
)

Average

支持

 
Function Average ( _
source As IQueryable(Of Nullable(Of Double)) _
) As Nullable(Of Double)
 
Nullable<double> Average(
this IQueryable<Nullable<double>> source
)

Average

支持

 
Function Average ( _
source As IQueryable(Of Nullable(Of Integer)) _
) As Nullable(Of Double)
 
Nullable<double> Average(
this IQueryable<Nullable<int>> source
)

Average

支持

 
Function Average ( _
source As IQueryable(Of Nullable(Of Long)) _
) As Nullable(Of Double)
 
Nullable<double> Average(
this IQueryable<Nullable<long>> source
)

Average

支持

 
Function Average ( _
source As IQueryable(Of Nullable(Of Single)) _
) As Nullable(Of Single)
 
Nullable<float> Average(
this IQueryable<Nullable<float>> source
)

Average

支持

 
Function Average ( _
source As IQueryable(Of Single) _
) As Single
 
float Average(
this IQueryable<float> source
)

Average

不支持

 
Function Average(Of TSource) ( _
source As IQueryable(Of TSource), _
selector As Expression(Of Func(Of TSource, Integer)) _
) As Double
 
double Average<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, int>> selector
)

Average

不支持

 
Function Average(Of TSource) ( _
source As IQueryable(Of TSource), _
selector As Expression(Of Func(Of TSource, Nullable(Of Integer))) _
) As Nullable(Of Double)
 
Nullable<double> Average<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, Nullable<int>>> selector
)

Average

不支持

 
Function Average(Of TSource) ( _
source As IQueryable(Of TSource), _
selector As Expression(Of Func(Of TSource, Long)) _
) As Double
 
double Average<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, long>> selector
)

Average

不支持

 
Function Average(Of TSource) ( _
source As IQueryable(Of TSource), _
selector As Expression(Of Func(Of TSource, Nullable(Of Long))) _
) As Nullable(Of Double)
 
Nullable<double> Average<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, Nullable<long>>> selector
)

Average

不支持

 
Function Average(Of TSource) ( _
source As IQueryable(Of TSource), _
selector As Expression(Of Func(Of TSource, Single)) _
) As Single
 
float Average<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, float>> selector
)

Average

不支持

 
Function Average(Of TSource) ( _
source As IQueryable(Of TSource), _
selector As Expression(Of Func(Of TSource, Nullable(Of Single))) _
) As Nullable(Of Single)
 
Nullable<float> Average<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, Nullable<float>>> selector
)

Average

不支持

 
Function Average(Of TSource) ( _
source As IQueryable(Of TSource), _
selector As Expression(Of Func(Of TSource, Double)) _
) As Double
 
double Average<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, double>> selector
)

Average

不支持

 
Function Average(Of TSource) ( _
source As IQueryable(Of TSource), _
selector As Expression(Of Func(Of TSource, Nullable(Of Double))) _
) As Nullable(Of Double)
 
Nullable<double> Average<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, Nullable<double>>> selector
)

Average

不支持

 
Function Average(Of TSource) ( _
source As IQueryable(Of TSource), _
selector As Expression(Of Func(Of TSource, Decimal)) _
) As Decimal
 
decimal Average<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, decimal>> selector
)

Average

不支持

 
Function Average(Of TSource) ( _
source As IQueryable(Of TSource), _
selector As Expression(Of Func(Of TSource, Nullable(Of Decimal))) _
) As Nullable(Of Decimal)
 
Nullable<decimal> Average<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, Nullable<decimal>>> selector
)

Count

支持

 
Function Count(Of TSource) ( _
source As IQueryable(Of TSource) _
) As Integer
 
int Count<TSource>(
this IQueryable<TSource> source
)

Count

不支持

 
Function Count(Of TSource) ( _
source As IQueryable(Of TSource), _
predicate As Expression(Of Func(Of TSource, Boolean)) _
) As Integer
 
int Count<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, bool>> predicate
)

LongCount

支持

 
Function LongCount(Of TSource) ( _
source As IQueryable(Of TSource) _
) As Long
 
long LongCount<TSource>(
this IQueryable<TSource> source
)

LongCount

不支持

 
Function LongCount(Of TSource) ( _
source As IQueryable(Of TSource), _
predicate As Expression(Of Func(Of TSource, Boolean)) _
) As Long
 
long LongCount<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, bool>> predicate
)

Max

支持

 
Function Max(Of TSource) ( _
source As IQueryable(Of TSource) _
) As TSource
 
TSource Max<TSource>(
this IQueryable<TSource> source
)

Max

不支持

 
Function Max(Of TSource, TResult) ( _
source As IQueryable(Of TSource), _
selector As Expression(Of Func(Of TSource, TResult)) _
) As TResult
 
TResult Max<TSource, TResult>(
this IQueryable<TSource> source,
Expression<Func<TSource, TResult>> selector
)

Min

支持

 
Function Min(Of TSource) ( _
source As IQueryable(Of TSource) _
) As TSource
 
TSource Min<TSource>(
this IQueryable<TSource> source
)

Min

不支持

 
Function Min(Of TSource, TResult) ( _
source As IQueryable(Of TSource), _
selector As Expression(Of Func(Of TSource, TResult)) _
) As TResult
 
TResult Min<TSource, TResult>(
this IQueryable<TSource> source,
Expression<Func<TSource, TResult>> selector
)

Sum

支持

 
Function Sum ( _
source As IQueryable(Of Decimal) _
) As Decimal
 
decimal Sum(
this IQueryable<decimal> source
)

Sum

支持

 
Function Sum ( _
source As IQueryable(Of Double) _
) As Double
 
double Sum(
this IQueryable<double> source
)

Sum

支持

 
Function Sum ( _
source As IQueryable(Of Integer) _
) As Integer
 
int Sum(
this IQueryable<int> source
)

Sum

支持

 
Function Sum ( _
source As IQueryable(Of Long) _
) As Long
 
long Sum(
this IQueryable<long> source
)

Sum

支持

 
Function Sum ( _
source As IQueryable(Of Nullable(Of Decimal)) _
) As Nullable(Of Decimal)
 
Nullable<decimal> Sum(
this IQueryable<Nullable<decimal>> source
)

Sum

支持

 
Function Sum ( _
source As IQueryable(Of Nullable(Of Double)) _
) As Nullable(Of Double)
 
Function Sum ( _
source As IQueryable(Of Nullable(Of Double)) _
) As Nullable(Of Double)Nullable<double> Sum(
this IQueryable<Nullable<double>> source
)

Sum

支持

 
Function Sum ( _
source As IQueryable(Of Nullable(Of Integer)) _
) As Nullable(Of Integer)
 
Nullable<int> Sum(
this IQueryable<Nullable<int>> source
)

Sum

支持

 
Function Sum ( _
source As IQueryable(Of Nullable(Of Long)) _
) As Nullable(Of Long)
 
Nullable<long> Sum(
this IQueryable<Nullable<long>> source
)

Sum

支持

 
Function Sum ( _
source As IQueryable(Of Nullable(Of Single)) _
) As Nullable(Of Single)
 
Nullable<float> Sum(
this IQueryable<Nullable<float>> source
)

Sum

支持

 
Function Sum ( _
source As IQueryable(Of Single) _
) As Single
 
float Sum(
this IQueryable<float> source
)

Sum

不支持

 
Function Sum(Of TSource) ( _
source As IQueryable(Of TSource), _
selector As Expression(Of Func(Of TSource, Integer)) _
) As Integer
 
int Sum<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, int>> selector
)

Sum

不支持

 
Function Sum(Of TSource) ( _
source As IQueryable(Of TSource), _
selector As Expression(Of Func(Of TSource, Nullable(Of Integer))) _
) As Nullable(Of Integer)
 
Nullable<int> Sum<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, Nullable<int>>> selector
)

Sum

不支持

 
Function Sum(Of TSource) ( _
source As IQueryable(Of TSource), _
selector As Expression(Of Func(Of TSource, Long)) _
) As Long
 
long Sum<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, long>> selector
)

Sum

不支持

 
Function Sum(Of TSource) ( _
source As IQueryable(Of TSource), _
selector As Expression(Of Func(Of TSource, Nullable(Of Long))) _
) As Nullable(Of Long)
 
Nullable<long> Sum<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, Nullable<long>>> selector
)

Sum

不支持

 
Function Sum(Of TSource) ( _
source As IQueryable(Of TSource), _
selector As Expression(Of Func(Of TSource, Nullable(Of Single))) _
) As Nullable(Of Single)
 
Nullable<float> Sum<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, Nullable<float>>> selector
)

Sum

不支持

 
Function Sum(Of TSource) ( _
source As IQueryable(Of TSource), _
selector As Expression(Of Func(Of TSource, Single)) _
) As Single
 
float Sum<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, float>> selector
)

Sum

不支持

 
Function Sum(Of TSource) ( _
source As IQueryable(Of TSource), _
selector As Expression(Of Func(Of TSource, Double)) _
) As Double
 
double Sum<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, double>> selector
)

Sum

不支持

 
Function Sum(Of TSource) ( _
source As IQueryable(Of TSource), _
selector As Expression(Of Func(Of TSource, Nullable(Of Double))) _
) As Nullable(Of Double)
 
Nullable<double> Sum<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, Nullable<double>>> selector
)

Sum

不支持

 
Function Sum(Of TSource) ( _
source As IQueryable(Of TSource), _
selector As Expression(Of Func(Of TSource, Decimal)) _
) As Decimal
 
decimal Sum<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, decimal>> selector
)

Sum

不支持

 
Function Sum(Of TSource) ( _
source As IQueryable(Of TSource), _
selector As Expression(Of Func(Of TSource, Nullable(Of Decimal))) _
) As Nullable(Of Decimal)
 
Nullable<decimal> Sum<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, Nullable<decimal>>> selector
)

类型方法

实体框架 中支持用于处理 CLR 类型转换和测试的 LINQ 标准查询运算符。 LINQ to Entities 中仅支持映射到概念模型类型的 CLR 类型。 有关概念模型类型的列表，请参见概念模型类型。 下表列出了支持的和不支持的类型方法。

方法 支持 Visual Basic 函数签名 C# 方法签名

Cast

对 EDM 基元类型支持

 
Function Cast(Of TResult) ( _
source As IQueryable _
) As IQueryable(Of TResult)
 
IQueryable<TResult> Cast<TResult>(
this IQueryable source
)

OfType

对 EntityType 支持

 
Function OfType(Of TResult) ( _
source As IQueryable _
) As IQueryable(Of TResult)
 
IQueryable<TResult> OfType<TResult>(
this IQueryable source
)

分页方法

有些 LINQ 分页方法在 LINQ to Entities 查询中不受支持。 有关更多信息，请参见 LINQ to Entities 查询中的标准查询运算符。 下表列出了支持的和不支持的分页方法。

方法 支持 Visual Basic 函数签名 C# 方法签名

ElementAt

不支持

 
Function ElementAt(Of TSource) ( _
source As IQueryable(Of TSource), _
index As Integer _
) As TSource
 
TSource ElementAt<TSource>(
this IQueryable<TSource> source,
int index
)

ElementAtOrDefault

不支持

 
Function ElementAtOrDefault(Of TSource) ( _
source As IQueryable(Of TSource), _
index As Integer _
) As TSource
 
TSource ElementAtOrDefault<TSource>(
this IQueryable<TSource> source,
int index
)

First

支持

 
Function First(Of TSource) ( _
source As IQueryable(Of TSource) _
) As TSource
 
TSource First<TSource>(
this IQueryable<TSource> source
)

First

支持

 
Function First(Of TSource) ( _
source As IQueryable(Of TSource), _
predicate As Expression(Of Func(Of TSource, Boolean)) _
) As TSource
 
TSource First<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, bool>> predicate
)

FirstOrDefault

支持

 
Function FirstOrDefault(Of TSource) ( _
source As IQueryable(Of TSource) _
) As TSource
 
TSource FirstOrDefault<TSource>(
this IQueryable<TSource> source
)

FirstOrDefault

支持

 
Function FirstOrDefault(Of TSource) ( _
source As IQueryable(Of TSource), _
predicate As Expression(Of Func(Of TSource, Boolean)) _
) As TSource
 
TSource FirstOrDefault<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, bool>> predicate
)

Last

不支持

 
Function Last(Of TSource) ( _
source As IQueryable(Of TSource) _
) As TSource
 
TSource Last<TSource>(
this IQueryable<TSource> source
)

Last

不支持

 
Function Last(Of TSource) ( _
source As IQueryable(Of TSource), _
predicate As Expression(Of Func(Of TSource, Boolean)) _
) As TSource
 
TSource Last<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, bool>> predicate
)

LastOrDefault

不支持

 
Function LastOrDefault(Of TSource) ( _
source As IQueryable(Of TSource) _
) As TSource
 
TSource LastOrDefault<TSource>(
this IQueryable<TSource> source
)

LastOrDefault

不支持

 
Function LastOrDefault(Of TSource) ( _
source As IQueryable(Of TSource), _
predicate As Expression(Of Func(Of TSource, Boolean)) _
) As TSource
 
TSource LastOrDefault<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, bool>> predicate
)

Single

支持

 
Function Single(Of TSource) ( _
source As IQueryable(Of TSource) _
) As TSource
 
TSource Single<TSource>(
this IQueryable<TSource> source
)

Single

支持

 
Function Single(Of TSource) ( _
source As IQueryable(Of TSource), _
predicate As Expression(Of Func(Of TSource, Boolean)) _
) As TSource
 
TSource Single<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, bool>> predicate
)

SingleOrDefault

支持

 
Function SingleOrDefault(Of TSource) ( _
source As IQueryable(Of TSource) _
) As TSource
 
TSource SingleOrDefault<TSource>(
this IQueryable<TSource> source
)

SingleOrDefault

支持

 
Function SingleOrDefault(Of TSource) ( _
source As IQueryable(Of TSource), _
predicate As Expression(Of Func(Of TSource, Boolean)) _
) As TSource
 
TSource SingleOrDefault<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, bool>> predicate
)

Skip

支持

 
Function Skip(Of TSource) ( _
source As IQueryable(Of TSource), _
count As Integer _
) As IQueryable(Of TSource)
 
IQueryable<TSource> Skip<TSource>(
this IQueryable<TSource> source,
int count
)

SkipWhile

不支持

 
Function SkipWhile(Of TSource) ( _
source As IQueryable(Of TSource), _
predicate As Expression(Of Func(Of TSource, Boolean)) _
) As IQueryable(Of TSource)
 
IQueryable<TSource> SkipWhile<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, bool>> predicate
)

SkipWhile

不支持

 
Function SkipWhile(Of TSource) ( _
source As IQueryable(Of TSource), _
predicate As Expression(Of Func(Of TSource, Integer, Boolean)) _
) As IQueryable(Of TSource)
 
IQueryable<TSource> SkipWhile<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, int, bool>> predicate
)

Take

支持

 
Function Take(Of TSource) ( _
source As IQueryable(Of TSource), _
count As Integer _
) As IQueryable(Of TSource)
 
IQueryable<TSource> Take<TSource>(
this IQueryable<TSource> source,
int count
)

TakeWhile

不支持

 
Function TakeWhile(Of TSource) ( _
source As IQueryable(Of TSource), _
predicate As Expression(Of Func(Of TSource, Boolean)) _
) As IQueryable(Of TSource)
 
IQueryable<TSource> TakeWhile<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, bool>> predicate
)

TakeWhile

不支持

 
Function TakeWhile(Of TSource) ( _
source As IQueryable(Of TSource), _
predicate As Expression(Of Func(Of TSource, Integer, Boolean)) _
) As IQueryable(Of TSource)
 
IQueryable<TSource> TakeWhile<TSource>(
this IQueryable<TSource> source,
Expression<Func<TSource, int, bool>> predicate
)

另请参见

概念

LINQ to Entities 查询中的标准查询运算符