Queryable.DistinctBy 方法

定义

命名空间:: System.Linq

程序集:: netstandard.dll, System.Linq.Queryable.dll

重要

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名称	说明
DistinctBy<TSource,TKey>(IQueryable<TSource>, Expression<Func<TSource,TKey>>)	根据指定的键选择器函数返回序列中的不同元素。
DistinctBy<TSource,TKey>(IQueryable<TSource>, Expression<Func<TSource,TKey>>, IEqualityComparer<TKey>)	根据指定的键选择器函数返回序列中的不同元素。

DistinctBy<TSource,TKey>(IQueryable<TSource>, Expression<Func<TSource,TKey>>)

Source:: Queryable.cs

Source:: Queryable.cs

Source:: Queryable.cs

Source:: Queryable.cs

Source:: Queryable.cs

根据指定的键选择器函数返回序列中的不同元素。

public:
generic <typename TSource, typename TKey>
[System::Runtime::CompilerServices::Extension]
 static System::Linq::IQueryable<TSource> ^ DistinctBy(System::Linq::IQueryable<TSource> ^ source, System::Linq::Expressions::Expression<Func<TSource, TKey> ^> ^ keySelector);

public static System.Linq.IQueryable<TSource> DistinctBy<TSource,TKey>(this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,TKey>> keySelector);

[System.Diagnostics.CodeAnalysis.RequiresDynamicCode("Enumerating collections as IQueryable can require creating new generic types or methods, which requires creating code at runtime. This may not work when AOT compiling.")]
public static System.Linq.IQueryable<TSource> DistinctBy<TSource,TKey>(this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,TKey>> keySelector);

static member DistinctBy : System.Linq.IQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, 'Key>> -> System.Linq.IQueryable<'Source>

[<System.Diagnostics.CodeAnalysis.RequiresDynamicCode("Enumerating collections as IQueryable can require creating new generic types or methods, which requires creating code at runtime. This may not work when AOT compiling.")>]
static member DistinctBy : System.Linq.IQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, 'Key>> -> System.Linq.IQueryable<'Source>

<Extension()>
Public Function DistinctBy(Of TSource, TKey) (source As IQueryable(Of TSource), keySelector As Expression(Of Func(Of TSource, TKey))) As IQueryable(Of TSource)

类型参数

TSource

的元素 source的类型。

TKey

要区分元素的键的类型。

参数

source: IQueryable<TSource>

要从中删除重复元素的序列。

keySelector: Expression<Func<TSource,TKey>>

用于提取每个元素的键的函数。

IQueryable<TSource>

一个包含源序列中不同元素的元素 IQueryable<T> 。

属性: RequiresDynamicCodeAttribute

例外

ArgumentNullException

source 是 null。

适用于

DistinctBy<TSource,TKey>(IQueryable<TSource>, Expression<Func<TSource,TKey>>, IEqualityComparer<TKey>)

Source:: Queryable.cs

Source:: Queryable.cs

Source:: Queryable.cs

Source:: Queryable.cs

Source:: Queryable.cs

根据指定的键选择器函数返回序列中的不同元素。

public:
generic <typename TSource, typename TKey>
[System::Runtime::CompilerServices::Extension]
 static System::Linq::IQueryable<TSource> ^ DistinctBy(System::Linq::IQueryable<TSource> ^ source, System::Linq::Expressions::Expression<Func<TSource, TKey> ^> ^ keySelector, System::Collections::Generic::IEqualityComparer<TKey> ^ comparer);

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

[System.Diagnostics.CodeAnalysis.RequiresDynamicCode("Enumerating collections as IQueryable can require creating new generic types or methods, which requires creating code at runtime. This may not work when AOT compiling.")]
public static System.Linq.IQueryable<TSource> DistinctBy<TSource,TKey>(this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,TKey>> keySelector, System.Collections.Generic.IEqualityComparer<TKey>? comparer);

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

[<System.Diagnostics.CodeAnalysis.RequiresDynamicCode("Enumerating collections as IQueryable can require creating new generic types or methods, which requires creating code at runtime. This may not work when AOT compiling.")>]
static member DistinctBy : System.Linq.IQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, 'Key>> * System.Collections.Generic.IEqualityComparer<'Key> -> System.Linq.IQueryable<'Source>

<Extension()>
Public Function DistinctBy(Of TSource, TKey) (source As IQueryable(Of TSource), keySelector As Expression(Of Func(Of TSource, TKey)), comparer As IEqualityComparer(Of TKey)) As IQueryable(Of TSource)