MemoryCache 类

定义

表示实现内存中缓存的类型。Represents the type that implements an in-memory cache.

public ref class MemoryCache : System::Runtime::Caching::ObjectCache, IDisposable
public class MemoryCache : System.Runtime.Caching.ObjectCache, IDisposable
type MemoryCache = class
    inherit ObjectCache
    interface IEnumerable
    interface IDisposable
Public Class MemoryCache
Inherits ObjectCache
Implements IDisposable
继承
MemoryCache
实现

示例

下面的示例声明对默认内存缓存实例的引用。The following example declares a reference to the default memory cache instance. 缓存条目使用 CacheItemPolicy 对象提供缓存条目的逐出和过期详细信息。The cache entry uses a CacheItemPolicy object to provide eviction and expiration details for the cache entry. 它还使用 ChangeMonitor 对象来监视文件系统中的源数据(即文件)的状态。It also uses a ChangeMonitor object to monitor the state of the source data (which is a file) on the file system.

Private Sub btnGet_Click(ByVal sender As Object, ByVal e As EventArgs)   
    Dim cache As ObjectCache = MemoryCache.[Default]   
    Dim fileContents As String = TryCast(cache("filecontents"), String)   
  
    If fileContents Is Nothing Then   
        Dim policy As New CacheItemPolicy()   
        Dim filePaths As New List(Of String)()   
        filePaths.Add("c:\cache\example.txt")   
  
        policy.ChangeMonitors.Add(New HostFileChangeMonitor(filePaths))   
  
        ' Fetch the file contents.  
        fileContents = File.ReadAllText("c:\cache\example.txt")   
  
        cache.[Set]("filecontents", fileContents, policy)   
    End If   
  
    Label1.Text = fileContents  
End Sub  
private void btnGet_Click(object sender, EventArgs e)  
{  
    ObjectCache cache = MemoryCache.Default;  
    string fileContents = cache["filecontents"] as string;  
  
    if (fileContents == null)  
    {  
        CacheItemPolicy policy = new CacheItemPolicy();  
  
        List<string> filePaths = new List<string>();  
        filePaths.Add("c:\\cache\\example.txt");  
  
        policy.ChangeMonitors.Add(new   
        HostFileChangeMonitor(filePaths));  
  
        // Fetch the file contents.  
        fileContents =   
            File.ReadAllText("c:\\cache\\example.txt");  
  
        cache.Set("filecontents", fileContents, policy);  
    }  
  
    Label1.Text = fileContents;  
}  

注解

MemoryCache 类是抽象 ObjectCache 类的具体实现。The MemoryCache class is a concrete implementation of the abstract ObjectCache class.

备注

MemoryCache 类类似于 ASP.NET Cache 类。The MemoryCache class is similar to the ASP.NET Cache class. 如果使用了 ASP.NET Cache 类,则 MemoryCache 类具有许多用于访问缓存的属性和方法。The MemoryCache class has many properties and methods for accessing the cache that will be familiar to you if you have used the ASP.NET Cache class. CacheMemoryCache 类之间的主要区别在于 MemoryCache 类已更改,使其可供不是 ASP.NET 应用程序的 .NET Framework.NET Framework 应用程序使用。The main differences between the Cache and MemoryCache classes are that the MemoryCache class has been changed to make it usable by .NET Framework.NET Framework applications that are not ASP.NET applications. 例如,MemoryCache 类对 System.Web 程序集没有依赖项。For example, the MemoryCache class has no dependencies on the System.Web assembly. 另一差别在于,您可以创建 MemoryCache 类的多个实例,以便在同一个应用程序和同一 AppDomain 实例中使用。Another difference is that you can create multiple instances of the MemoryCache class for use in the same application and in the same AppDomain instance.

MemoryCache 类不允许 null 作为缓存中的值。The MemoryCache class does not allow null as a value in the cache. 添加或更改值为 null 的缓存条目的任何尝试都将失败。Any attempt to add or change a cache entry with a value of null will fail.

MemoryCache 类型不实现缓存区域The MemoryCache type does not implement cache regions. 因此,在调用实现包含区域参数的基方法 MemoryCache 方法时,不要传递参数的值。Therefore, when you call MemoryCache methods that implement base methods that contain a parameter for regions, do not pass a value for the parameter. 使用 region 参数的方法都提供默认 null 值。The methods that use the region parameter all supply a default null value. 例如,MemoryCache.AddOrGetExisting 方法重载具有一个 regionName 参数,其默认值为 nullFor example, the MemoryCache.AddOrGetExisting method overload has a regionName parameter whose default value is null.

构造函数

MemoryCache(String, NameValueCollection)

初始化 MemoryCache 类的新实例。Initializes a new instance of the MemoryCache class.

MemoryCache(String, NameValueCollection, Boolean)

初始化 MemoryCache 类的新实例。Initializes a new instance of the MemoryCache class.

属性

CacheMemoryLimit

获取计算机上缓存可使用的内存量(以字节为单位)。Gets the amount of memory on the computer, in bytes, that can be used by the cache.

Default

获取对默认 MemoryCache 实例的引用。Gets a reference to the default MemoryCache instance.

DefaultCacheCapabilities

获取缓存提供的功能的说明。Gets a description of the features that the cache provides.

Item[String]

通过使用 MemoryCache 类的实例的默认索引器属性,获取或设置缓存中的值。Gets or sets a value in the cache by using the default indexer property for an instance of the MemoryCache class.

Name

获取缓存的名称。Gets the name of the cache.

PhysicalMemoryLimit

获取缓存可使用的物理内存的百分比。Gets the percentage of physical memory that the cache can use.

PollingInterval

获取在缓存更新其内存统计信息之前需等待的最大时间量。Gets the maximum time after which the cache updates its memory statistics.

方法

Add(CacheItem, CacheItemPolicy)

将缓存项作为 CacheItem 实例插入到缓存中,并添加有关如何逐出该项的详细信息。Inserts a cache entry into the cache as a CacheItem instance, and adds details about how the entry should be evicted.

Add(String, Object, CacheItemPolicy, String)

在派生类中重写时,向缓存中插入缓存项,同时指定有关如何逐出该项的信息。When overridden in a derived class, inserts a cache entry into the cache, specifying information about how the entry will be evicted.

(继承自 ObjectCache)
Add(String, Object, DateTimeOffset, String)

在派生类中重写时,向缓存中插入缓存项,而不会覆盖任何现有的缓存项。When overridden in a derived class, inserts a cache entry into the cache without overwriting any existing cache entry.

(继承自 ObjectCache)
AddOrGetExisting(CacheItem, CacheItemPolicy)

使用指定的 CacheItem 实例以及有关如何逐出该项的详细信息将某个缓存项添加到缓存中。Adds a cache entry into the cache using the specified CacheItem instance and details about how to evict the entry.

AddOrGetExisting(String, Object, CacheItemPolicy, String)

通过使用指定的键、值和有关如何逐出缓存项的指定详细信息,将某个缓存项插入缓存中。Inserts a cache entry into the cache using the specified key and value and the specified details for how it is to be evicted.

AddOrGetExisting(String, Object, DateTimeOffset, String)

通过使用指定的键、值和绝对过期值,将某个缓存项添加到缓存中。Adds a cache entry into the cache using the specified key and a value and an absolute expiration value.

Contains(String, String)

确定缓存中是否存在某个缓存项。Determines whether a cache entry exists in the cache.

CreateCacheEntryChangeMonitor(IEnumerable<String>, String)

创建一个 CacheEntryChangeMonitor 对象,该对象可触发事件以响应对指定缓存项的更改。Creates a CacheEntryChangeMonitor object that can trigger events in response to changes to specified cache entries.

Dispose()

释放由 MemoryCache 类的当前实例占用的所有资源。Releases all resources that are used by the current instance of the MemoryCache class.

Equals(Object)

确定指定对象是否等于当前对象。Determines whether the specified object is equal to the current object.

(继承自 Object)
Get(String, String)

从缓存中返回一个项。Returns an entry from the cache.

GetCacheItem(String, String)

从缓存中返回 CacheItem 实例形式的指定项。Returns the specified entry from the cache as a CacheItem instance.

GetCount(String)

返回缓存中的缓存项总数。Returns the total number of cache entries in the cache.

GetEnumerator()

创建一个枚举器,它可用于循环访问缓存项的集合。Creates an enumerator that can be used to iterate through a collection of cache entries.

GetHashCode()

用作默认哈希函数。Serves as the default hash function.

(继承自 Object)
GetLastSize(String)

获取已命名区域的大小。Gets the size of the named region.

GetType()

获取当前实例的 TypeGets the Type of the current instance.

(继承自 Object)
GetValues(IEnumerable<String>, String)

返回与指定的键对应的一组缓存项。Returns a set of cache entries that correspond to the specified keys.

GetValues(String, String[])

获取与指定的键对应的一组缓存项。Gets a set of cache entries that correspond to the specified keys.

(继承自 ObjectCache)
MemberwiseClone()

创建当前 Object 的浅表副本。Creates a shallow copy of the current Object.

(继承自 Object)
Remove(String, CacheEntryRemovedReason, String)

使用原因从缓存中删除缓存项。Removes a cache entry from the cache using the reason.

Remove(String, String)

从缓存中移除某个缓存项。Removes a cache entry from the cache.

Set(CacheItem, CacheItemPolicy)

使用 CacheItem 实例将某个缓存项插入缓存中,以便为该缓存项提供键和值。Inserts a cache entry into the cache by using a CacheItem instance to supply the key and value for the cache entry.

Set(String, Object, CacheItemPolicy, String)

通过使用键、值和逐出设置,将某个缓存项插入缓存中。Inserts a cache entry into the cache by using a key and a value and eviction.

Set(String, Object, DateTimeOffset, String)

使用键和值将某个缓存项插入缓存中,并指定基于时间的过期详细信息。Inserts a cache entry into the cache by using a key and a value and specifies time-based expiration details.

ToString()

返回表示当前对象的字符串。Returns a string that represents the current object.

(继承自 Object)
Trim(Int32)

从缓存对象中移除指定百分比的缓存项。Removes a specified percentage of cache entries from the cache object.

显式接口实现

IEnumerable.GetEnumerator()

为在泛型集合上进行迭代提供支持。Provides support for iteration over a generic collection.

IEnumerable<KeyValuePair<String,Object>>.GetEnumerator()

支持对强类型集合迭代。Supports iteration over a strongly typed collection.

(继承自 ObjectCache)

扩展方法

CopyToDataTable<T>(IEnumerable<T>)

在给定其泛型参数 DataTableDataRow 的输入 IEnumerable<T> 对象的情况下,返回包含 T 对象副本的 DataRowReturns a DataTable that contains copies of the DataRow objects, given an input IEnumerable<T> object where the generic parameter T is DataRow.

CopyToDataTable<T>(IEnumerable<T>, DataTable, LoadOption)

在给定其泛型参数 DataRowDataTable 的输入 IEnumerable<T> 对象的情况下,将 T 对象复制到指定的 DataRowCopies DataRow objects to the specified DataTable, given an input IEnumerable<T> object where the generic parameter T is DataRow.

CopyToDataTable<T>(IEnumerable<T>, DataTable, LoadOption, FillErrorEventHandler)

在给定其泛型参数 DataRowDataTable 的输入 IEnumerable<T> 对象的情况下,将 T 对象复制到指定的 DataRowCopies DataRow objects to the specified DataTable, given an input IEnumerable<T> object where the generic parameter T is DataRow.

Aggregate<TSource>(IEnumerable<TSource>, Func<TSource,TSource,TSource>)

对序列应用累加器函数。Applies an accumulator function over a sequence.

Aggregate<TSource,TAccumulate>(IEnumerable<TSource>, TAccumulate, Func<TAccumulate,TSource,TAccumulate>)

对序列应用累加器函数。Applies an accumulator function over a sequence. 将指定的种子值用作累加器初始值。The specified seed value is used as the initial accumulator value.

Aggregate<TSource,TAccumulate,TResult>(IEnumerable<TSource>, TAccumulate, Func<TAccumulate,TSource,TAccumulate>, Func<TAccumulate,TResult>)

对序列应用累加器函数。Applies an accumulator function over a sequence. 将指定的种子值用作累加器的初始值,并使用指定的函数选择结果值。The specified seed value is used as the initial accumulator value, and the specified function is used to select the result value.

All<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)

确定序列中的所有元素是否都满足条件。Determines whether all elements of a sequence satisfy a condition.

Any<TSource>(IEnumerable<TSource>)

确定序列是否包含任何元素。Determines whether a sequence contains any elements.

Any<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)

确定序列中是否存在任意一个元素满足条件。Determines whether any element of a sequence satisfies a condition.

Append<TSource>(IEnumerable<TSource>, TSource)

将一个值追加到序列末尾。Appends a value to the end of the sequence.

AsEnumerable<TSource>(IEnumerable<TSource>)

返回类型化为 IEnumerable<T> 的输入。Returns the input typed as IEnumerable<T>.

Average<TSource>(IEnumerable<TSource>, Func<TSource,Decimal>)

计算 Decimal 值序列的平均值,这些值可通过对输入序列的每个元素调用转换函数获得。Computes the average of a sequence of Decimal values that are obtained by invoking a transform function on each element of the input sequence.

Average<TSource>(IEnumerable<TSource>, Func<TSource,Double>)

计算 Double 值序列的平均值,这些值可通过对输入序列的每个元素调用转换函数获得。Computes the average of a sequence of Double values that are obtained by invoking a transform function on each element of the input sequence.

Average<TSource>(IEnumerable<TSource>, Func<TSource,Int32>)

计算 Int32 值序列的平均值,这些值可通过对输入序列的每个元素调用转换函数获得。Computes the average of a sequence of Int32 values that are obtained by invoking a transform function on each element of the input sequence.

Average<TSource>(IEnumerable<TSource>, Func<TSource,Int64>)

计算 Int64 值序列的平均值,这些值可通过对输入序列的每个元素调用转换函数获得。Computes the average of a sequence of Int64 values that are obtained by invoking a transform function on each element of the input sequence.

Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Decimal>>)

计算可以为 null 的 Decimal 值序列的平均值,这些值可通过对输入序列的每个元素调用转换函数获得。Computes the average of a sequence of nullable Decimal values that are obtained by invoking a transform function on each element of the input sequence.

Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Double>>)

计算可以为 null 的 Double 值序列的平均值,这些值可通过对输入序列的每个元素调用转换函数获得。Computes the average of a sequence of nullable Double values that are obtained by invoking a transform function on each element of the input sequence.

Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int32>>)

计算可以为 null 的 Int32 值序列的平均值,这些值可通过对输入序列的每个元素调用转换函数获得。Computes the average of a sequence of nullable Int32 values that are obtained by invoking a transform function on each element of the input sequence.

Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int64>>)

计算可以为 null 的 Int64 值序列的平均值,这些值可通过对输入序列的每个元素调用转换函数获得。Computes the average of a sequence of nullable Int64 values that are obtained by invoking a transform function on each element of the input sequence.

Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Single>>)

计算可以为 null 的 Single 值序列的平均值,这些值可通过对输入序列的每个元素调用转换函数获得。Computes the average of a sequence of nullable Single values that are obtained by invoking a transform function on each element of the input sequence.

Average<TSource>(IEnumerable<TSource>, Func<TSource,Single>)

计算 Single 值序列的平均值,这些值可通过对输入序列的每个元素调用转换函数获得。Computes the average of a sequence of Single values that are obtained by invoking a transform function on each element of the input sequence.

Cast<TResult>(IEnumerable)

IEnumerable 的元素强制转换为指定的类型。Casts the elements of an IEnumerable to the specified type.

Concat<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)

连接两个序列。Concatenates two sequences.

Contains<TSource>(IEnumerable<TSource>, TSource)

通过使用默认的相等比较器确定序列是否包含指定的元素。Determines whether a sequence contains a specified element by using the default equality comparer.

Contains<TSource>(IEnumerable<TSource>, TSource, IEqualityComparer<TSource>)

通过使用指定的 IEqualityComparer<T> 确定序列是否包含指定的元素。Determines whether a sequence contains a specified element by using a specified IEqualityComparer<T>.

Count<TSource>(IEnumerable<TSource>)

返回序列中的元素数量。Returns the number of elements in a sequence.

Count<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)

返回表示在指定的序列中满足条件的元素数量的数字。Returns a number that represents how many elements in the specified sequence satisfy a condition.

DefaultIfEmpty<TSource>(IEnumerable<TSource>)

返回指定序列中的元素;如果序列为空,则返回单一实例集合中的类型参数的默认值。Returns the elements of the specified sequence or the type parameter's default value in a singleton collection if the sequence is empty.

DefaultIfEmpty<TSource>(IEnumerable<TSource>, TSource)

返回指定序列中的元素;如果序列为空,则返回单一实例集合中的指定值。Returns the elements of the specified sequence or the specified value in a singleton collection if the sequence is empty.

Distinct<TSource>(IEnumerable<TSource>)

通过使用默认的相等比较器对值进行比较,返回序列中的非重复元素。Returns distinct elements from a sequence by using the default equality comparer to compare values.

Distinct<TSource>(IEnumerable<TSource>, IEqualityComparer<TSource>)

通过使用指定的 IEqualityComparer<T> 对值进行比较,返回序列中的非重复元素。Returns distinct elements from a sequence by using a specified IEqualityComparer<T> to compare values.

ElementAt<TSource>(IEnumerable<TSource>, Int32)

返回序列中指定索引处的元素。Returns the element at a specified index in a sequence.

ElementAtOrDefault<TSource>(IEnumerable<TSource>, Int32)

返回序列中指定索引处的元素;如果索引超出范围,则返回默认值。Returns the element at a specified index in a sequence or a default value if the index is out of range.

Except<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)

通过使用默认的相等比较器对值进行比较,生成两个序列的差集。Produces the set difference of two sequences by using the default equality comparer to compare values.

Except<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>)

通过使用指定的 IEqualityComparer<T> 对值进行比较,生成两个序列的差集。Produces the set difference of two sequences by using the specified IEqualityComparer<T> to compare values.

First<TSource>(IEnumerable<TSource>)

返回序列中的第一个元素。Returns the first element of a sequence.

First<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)

返回序列中满足指定条件的第一个元素。Returns the first element in a sequence that satisfies a specified condition.

FirstOrDefault<TSource>(IEnumerable<TSource>)

返回序列中的第一个元素;如果序列中不包含任何元素,则返回默认值。Returns the first element of a sequence, or a default value if the sequence contains no elements.

FirstOrDefault<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)

返回序列中满足条件的第一个元素;如果未找到这样的元素,则返回默认值。Returns the first element of the sequence that satisfies a condition or a default value if no such element is found.

GroupBy<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)

根据指定的键选择器函数对序列中的元素进行分组。Groups the elements of a sequence according to a specified key selector function.

GroupBy<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IEqualityComparer<TKey>)

根据指定的键选择器函数对序列中的元素进行分组,并使用指定的比较器对键进行比较。Groups the elements of a sequence according to a specified key selector function and compares the keys by using a specified comparer.

GroupBy<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>)

根据指定的键选择器函数对序列中的元素进行分组,并且通过使用指定的函数对每个组中的元素进行投影。Groups the elements of a sequence according to a specified key selector function and projects the elements for each group by using a specified function.

GroupBy<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>, IEqualityComparer<TKey>)

根据键选择器函数对序列中的元素进行分组。Groups the elements of a sequence according to a key selector function. 通过使用比较器对键进行比较,并且通过使用指定的函数对每个组的元素进行投影。The keys are compared by using a comparer and each group's elements are projected by using a specified function.

GroupBy<TSource,TKey,TResult>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TKey,IEnumerable<TSource>,TResult>)

根据指定的键选择器函数对序列中的元素进行分组,并且从每个组及其键中创建结果值。Groups the elements of a sequence according to a specified key selector function and creates a result value from each group and its key.

GroupBy<TSource,TKey,TResult>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TKey,IEnumerable<TSource>,TResult>, IEqualityComparer<TKey>)

根据指定的键选择器函数对序列中的元素进行分组,并且从每个组及其键中创建结果值。Groups the elements of a sequence according to a specified key selector function and creates a result value from each group and its key. 通过使用指定的比较器对键进行比较。The keys are compared by using a specified comparer.

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

根据指定的键选择器函数对序列中的元素进行分组,并且从每个组及其键中创建结果值。Groups the elements of a sequence according to a specified key selector function and creates a result value from each group and its key. 通过使用指定的函数对每个组的元素进行投影。The elements of each group are projected by using a specified function.

GroupBy<TSource,TKey,TElement,TResult>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>, Func<TKey,IEnumerable<TElement>,TResult>, IEqualityComparer<TKey>)

根据指定的键选择器函数对序列中的元素进行分组,并且从每个组及其键中创建结果值。Groups the elements of a sequence according to a specified key selector function and creates a result value from each group and its key. 通过使用指定的比较器对键值进行比较,并且通过使用指定的函数对每个组的元素进行投影。Key values are compared by using a specified comparer, and the elements of each group are projected by using a specified function.

GroupJoin<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,IEnumerable<TInner>,TResult>)

基于键值等同性对两个序列的元素进行关联,并对结果进行分组。Correlates the elements of two sequences based on equality of keys and groups the results. 使用默认的相等比较器对键进行比较。The default equality comparer is used to compare keys.

GroupJoin<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,IEnumerable<TInner>,TResult>, IEqualityComparer<TKey>)

基于键值等同性对两个序列的元素进行关联,并对结果进行分组。Correlates the elements of two sequences based on key equality and groups the results. 使用指定的 IEqualityComparer<T> 对键进行比较。A specified IEqualityComparer<T> is used to compare keys.

Intersect<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)

通过使用默认的相等比较器对值进行比较,生成两个序列的交集。Produces the set intersection of two sequences by using the default equality comparer to compare values.

Intersect<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>)

通过使用指定的 IEqualityComparer<T> 对值进行比较,生成两个序列的交集。Produces the set intersection of two sequences by using the specified IEqualityComparer<T> to compare values.

Join<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,TInner,TResult>)

基于匹配键对两个序列的元素进行关联。Correlates the elements of two sequences based on matching keys. 使用默认的相等比较器对键进行比较。The default equality comparer is used to compare keys.

Join<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,TInner,TResult>, IEqualityComparer<TKey>)

基于匹配键对两个序列的元素进行关联。Correlates the elements of two sequences based on matching keys. 使用指定的 IEqualityComparer<T> 对键进行比较。A specified IEqualityComparer<T> is used to compare keys.

Last<TSource>(IEnumerable<TSource>)

返回序列的最后一个元素。Returns the last element of a sequence.

Last<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)

返回序列中满足指定条件的最后一个元素。Returns the last element of a sequence that satisfies a specified condition.

LastOrDefault<TSource>(IEnumerable<TSource>)

返回序列中的最后一个元素;如果序列中不包含任何元素,则返回默认值。Returns the last element of a sequence, or a default value if the sequence contains no elements.

LastOrDefault<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)

返回序列中满足条件的最后一个元素;如果未找到这样的元素,则返回默认值。Returns the last element of a sequence that satisfies a condition or a default value if no such element is found.

LongCount<TSource>(IEnumerable<TSource>)

返回表示序列中元素总数的 Int64Returns an Int64 that represents the total number of elements in a sequence.

LongCount<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)

返回表示序列中满足条件的元素的数量的 Int64Returns an Int64 that represents how many elements in a sequence satisfy a condition.

Max<TSource>(IEnumerable<TSource>)

返回泛型序列中的最大值。Returns the maximum value in a generic sequence.

Max<TSource>(IEnumerable<TSource>, Func<TSource,Decimal>)

对序列中的每个元素调用转换函数,并返回最大的 Decimal 值。Invokes a transform function on each element of a sequence and returns the maximum Decimal value.

Max<TSource>(IEnumerable<TSource>, Func<TSource,Double>)

对序列中的每个元素调用转换函数,并返回最大的 Double 值。Invokes a transform function on each element of a sequence and returns the maximum Double value.

Max<TSource>(IEnumerable<TSource>, Func<TSource,Int32>)

对序列中的每个元素调用转换函数,并返回最大的 Int32 值。Invokes a transform function on each element of a sequence and returns the maximum Int32 value.

Max<TSource>(IEnumerable<TSource>, Func<TSource,Int64>)

对序列中的每个元素调用转换函数,并返回最大的 Int64 值。Invokes a transform function on each element of a sequence and returns the maximum Int64 value.

Max<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Decimal>>)

对序列中的每个元素调用转换函数,并返回可以为 null 的最大的 Decimal 值。Invokes a transform function on each element of a sequence and returns the maximum nullable Decimal value.

Max<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Double>>)

对序列中的每个元素调用转换函数,并返回可以为 null 的最大的 Double 值。Invokes a transform function on each element of a sequence and returns the maximum nullable Double value.

Max<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int32>>)

对序列中的每个元素调用转换函数,并返回可以为 null 的最大的 Int32 值。Invokes a transform function on each element of a sequence and returns the maximum nullable Int32 value.

Max<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int64>>)

对序列中的每个元素调用转换函数,并返回可以为 null 的最大的 Int64 值。Invokes a transform function on each element of a sequence and returns the maximum nullable Int64 value.

Max<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Single>>)

对序列中的每个元素调用转换函数,并返回可以为 null 的最大的 Single 值。Invokes a transform function on each element of a sequence and returns the maximum nullable Single value.

Max<TSource>(IEnumerable<TSource>, Func<TSource,Single>)

对序列中的每个元素调用转换函数,并返回最大的 Single 值。Invokes a transform function on each element of a sequence and returns the maximum Single value.

Max<TSource,TResult>(IEnumerable<TSource>, Func<TSource,TResult>)

对序列中的每个元素调用转换函数,并返回最大结果值。Invokes a transform function on each element of a generic sequence and returns the maximum resulting value.

Min<TSource>(IEnumerable<TSource>)

返回泛型序列中的最小值。Returns the minimum value in a generic sequence.

Min<TSource>(IEnumerable<TSource>, Func<TSource,Decimal>)

对序列中的每个元素调用转换函数,并返回最小的 Decimal 值。Invokes a transform function on each element of a sequence and returns the minimum Decimal value.

Min<TSource>(IEnumerable<TSource>, Func<TSource,Double>)

对序列中的每个元素调用转换函数,并返回最小的 Double 值。Invokes a transform function on each element of a sequence and returns the minimum Double value.

Min<TSource>(IEnumerable<TSource>, Func<TSource,Int32>)

对序列中的每个元素调用转换函数,并返回最小的 Int32 值。Invokes a transform function on each element of a sequence and returns the minimum Int32 value.

Min<TSource>(IEnumerable<TSource>, Func<TSource,Int64>)

对序列中的每个元素调用转换函数,并返回最小的 Int64 值。Invokes a transform function on each element of a sequence and returns the minimum Int64 value.

Min<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Decimal>>)

对序列中的每个元素调用转换函数,并返回可以为 null 的最小的 Decimal 值。Invokes a transform function on each element of a sequence and returns the minimum nullable Decimal value.

Min<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Double>>)

对序列中的每个元素调用转换函数,并返回可以为 null 的最小的 Double 值。Invokes a transform function on each element of a sequence and returns the minimum nullable Double value.

Min<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int32>>)

对序列中的每个元素调用转换函数,并返回可以为 null 的最小的 Int32 值。Invokes a transform function on each element of a sequence and returns the minimum nullable Int32 value.

Min<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int64>>)

对序列中的每个元素调用转换函数,并返回可以为 null 的最小的 Int64 值。Invokes a transform function on each element of a sequence and returns the minimum nullable Int64 value.

Min<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Single>>)

对序列中的每个元素调用转换函数,并返回可以为 null 的最小的 Single 值。Invokes a transform function on each element of a sequence and returns the minimum nullable Single value.

Min<TSource>(IEnumerable<TSource>, Func<TSource,Single>)

对序列中的每个元素调用转换函数,并返回最小的 Single 值。Invokes a transform function on each element of a sequence and returns the minimum Single value.

Min<TSource,TResult>(IEnumerable<TSource>, Func<TSource,TResult>)

对序列中的每个元素调用转换函数,并返回最小结果值。Invokes a transform function on each element of a generic sequence and returns the minimum resulting value.

OfType<TResult>(IEnumerable)

根据指定类型筛选 IEnumerable 的元素。Filters the elements of an IEnumerable based on a specified type.

OrderBy<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)

根据键按升序对序列的元素进行排序。Sorts the elements of a sequence in ascending order according to a key.

OrderBy<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IComparer<TKey>)

使用指定的比较器按升序对序列的元素进行排序。Sorts the elements of a sequence in ascending order by using a specified comparer.

OrderByDescending<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)

根据键按降序对序列的元素进行排序。Sorts the elements of a sequence in descending order according to a key.

OrderByDescending<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IComparer<TKey>)

使用指定的比较器按降序对序列的元素排序。Sorts the elements of a sequence in descending order by using a specified comparer.

Prepend<TSource>(IEnumerable<TSource>, TSource)

向序列的开头添加值。Adds a value to the beginning of the sequence.

Reverse<TSource>(IEnumerable<TSource>)

反转序列中元素的顺序。Inverts the order of the elements in a sequence.

Select<TSource,TResult>(IEnumerable<TSource>, Func<TSource,TResult>)

将序列中的每个元素投影到新表单。Projects each element of a sequence into a new form.

Select<TSource,TResult>(IEnumerable<TSource>, Func<TSource,Int32,TResult>)

通过合并元素的索引,将序列的每个元素投影到新窗体中。Projects each element of a sequence into a new form by incorporating the element's index.

SelectMany<TSource,TResult>(IEnumerable<TSource>, Func<TSource,IEnumerable<TResult>>)

将序列的每个元素投影到 IEnumerable<T> 并将结果序列合并为一个序列。Projects each element of a sequence to an IEnumerable<T> and flattens the resulting sequences into one sequence.

SelectMany<TSource,TResult>(IEnumerable<TSource>, Func<TSource,Int32,IEnumerable<TResult>>)

将序列的每个元素投影到 IEnumerable<T> 并将结果序列合并为一个序列。Projects each element of a sequence to an IEnumerable<T>, and flattens the resulting sequences into one sequence. 每个源元素的索引用于该元素的投影表。The index of each source element is used in the projected form of that element.

SelectMany<TSource,TCollection,TResult>(IEnumerable<TSource>, Func<TSource,IEnumerable<TCollection>>, Func<TSource,TCollection,TResult>)

将序列的每个元素投影到 IEnumerable<T>,并将结果序列合并为一个序列,并对其中每个元素调用结果选择器函数。Projects each element of a sequence to an IEnumerable<T>, flattens the resulting sequences into one sequence, and invokes a result selector function on each element therein.

SelectMany<TSource,TCollection,TResult>(IEnumerable<TSource>, Func<TSource,Int32,IEnumerable<TCollection>>, Func<TSource,TCollection,TResult>)

将序列的每个元素投影到 IEnumerable<T>,并将结果序列合并为一个序列,并对其中每个元素调用结果选择器函数。Projects each element of a sequence to an IEnumerable<T>, flattens the resulting sequences into one sequence, and invokes a result selector function on each element therein. 每个源元素的索引用于该元素的中间投影表。The index of each source element is used in the intermediate projected form of that element.

SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)

通过使用相应类型的默认相等比较器对序列的元素进行比较,以确定两个序列是否相等。Determines whether two sequences are equal by comparing the elements by using the default equality comparer for their type.

SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>)

通过使用指定的 IEqualityComparer<T> 来比较两个序列的元素,以确定这两个序列是否相等。Determines whether two sequences are equal by comparing their elements by using a specified IEqualityComparer<T>.

Single<TSource>(IEnumerable<TSource>)

返回序列的唯一元素;如果该序列并非恰好包含一个元素,则会引发异常。Returns the only element of a sequence, and throws an exception if there is not exactly one element in the sequence.

Single<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)

返回序列中满足指定条件的唯一元素;如果有多个这样的元素存在,则会引发异常。Returns the only element of a sequence that satisfies a specified condition, and throws an exception if more than one such element exists.

SingleOrDefault<TSource>(IEnumerable<TSource>)

返回序列中的唯一元素;如果该序列为空,则返回默认值;如果该序列包含多个元素,此方法将引发异常。Returns the only element of a sequence, or a default value if the sequence is empty; this method throws an exception if there is more than one element in the sequence.

SingleOrDefault<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)

返回序列中满足指定条件的唯一元素;如果这类元素不存在,则返回默认值;如果有多个元素满足该条件,此方法将引发异常。Returns the only element of a sequence that satisfies a specified condition or a default value if no such element exists; this method throws an exception if more than one element satisfies the condition.

Skip<TSource>(IEnumerable<TSource>, Int32)

跳过序列中指定数量的元素,然后返回剩余的元素。Bypasses a specified number of elements in a sequence and then returns the remaining elements.

SkipLast<TSource>(IEnumerable<TSource>, Int32)

返回一个新的可枚举集合,它包含 source 中的元素,但省略了源集合中的 count 个元素。Returns a new enumerable collection that contains the elements from source with the last count elements of the source collection omitted.

SkipWhile<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)

如果指定的条件为 true,则跳过序列中的元素,然后返回剩余的元素。Bypasses elements in a sequence as long as a specified condition is true and then returns the remaining elements.

SkipWhile<TSource>(IEnumerable<TSource>, Func<TSource,Int32,Boolean>)

如果指定的条件为 true,则跳过序列中的元素,然后返回剩余的元素。Bypasses elements in a sequence as long as a specified condition is true and then returns the remaining elements. 将在谓词函数的逻辑中使用元素的索引。The element's index is used in the logic of the predicate function.

Sum<TSource>(IEnumerable<TSource>, Func<TSource,Decimal>)

计算 Decimal 值序列的总和,这些值可通过对输入序列中的每个元素调用转换函数获得。Computes the sum of the sequence of Decimal values that are obtained by invoking a transform function on each element of the input sequence.

Sum<TSource>(IEnumerable<TSource>, Func<TSource,Double>)

计算 Double 值序列的总和,这些值可通过对输入序列中的每个元素调用转换函数获得。Computes the sum of the sequence of Double values that are obtained by invoking a transform function on each element of the input sequence.

Sum<TSource>(IEnumerable<TSource>, Func<TSource,Int32>)

计算 Int32 值序列的总和,这些值可通过对输入序列中的每个元素调用转换函数获得。Computes the sum of the sequence of Int32 values that are obtained by invoking a transform function on each element of the input sequence.

Sum<TSource>(IEnumerable<TSource>, Func<TSource,Int64>)

计算 Int64 值序列的总和,这些值可通过对输入序列中的每个元素调用转换函数获得。Computes the sum of the sequence of Int64 values that are obtained by invoking a transform function on each element of the input sequence.

Sum<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Decimal>>)

计算可以为 null 的 Decimal 值序列的总和,这些值可通过对输入序列的每个元素调用转换函数获得。Computes the sum of the sequence of nullable Decimal values that are obtained by invoking a transform function on each element of the input sequence.

Sum<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Double>>)

计算可以为 null 的 Double 值序列的总和,这些值可通过对输入序列的每个元素调用转换函数获得。Computes the sum of the sequence of nullable Double values that are obtained by invoking a transform function on each element of the input sequence.

Sum<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int32>>)

计算可以为 null 的 Int32 值序列的总和,这些值可通过对输入序列的每个元素调用转换函数获得。Computes the sum of the sequence of nullable Int32 values that are obtained by invoking a transform function on each element of the input sequence.

Sum<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int64>>)

计算可以为 null 的 Int64 值序列的总和,这些值可通过对输入序列的每个元素调用转换函数获得。Computes the sum of the sequence of nullable Int64 values that are obtained by invoking a transform function on each element of the input sequence.

Sum<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Single>>)

计算可以为 null 的 Single 值序列的总和,这些值可通过对输入序列的每个元素调用转换函数获得。Computes the sum of the sequence of nullable Single values that are obtained by invoking a transform function on each element of the input sequence.

Sum<TSource>(IEnumerable<TSource>, Func<TSource,Single>)

计算 Single 值序列的总和,这些值可通过对输入序列中的每个元素调用转换函数获得。Computes the sum of the sequence of Single values that are obtained by invoking a transform function on each element of the input sequence.

Take<TSource>(IEnumerable<TSource>, Int32)

从序列的开头返回指定数量的相邻元素。Returns a specified number of contiguous elements from the start of a sequence.

TakeLast<TSource>(IEnumerable<TSource>, Int32)

返回一个新的可枚举集合,它包含 count 中的最后 source 个元素。Returns a new enumerable collection that contains the last count elements from source.

TakeWhile<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)

只要指定的条件为 true,就会返回序列的元素。Returns elements from a sequence as long as a specified condition is true.

TakeWhile<TSource>(IEnumerable<TSource>, Func<TSource,Int32,Boolean>)

只要指定的条件为 true,就会返回序列的元素。Returns elements from a sequence as long as a specified condition is true. 将在谓词函数的逻辑中使用元素的索引。The element's index is used in the logic of the predicate function.

ToArray<TSource>(IEnumerable<TSource>)

IEnumerable<T> 中创建数组。Creates an array from a IEnumerable<T>.

ToDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)

根据指定的键选择器函数,从 IEnumerable<T> 创建一个 Dictionary<TKey,TValue>Creates a Dictionary<TKey,TValue> from an IEnumerable<T> according to a specified key selector function.

ToDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IEqualityComparer<TKey>)

根据指定的键选择器函数和键比较器,从 IEnumerable<T> 创建一个 Dictionary<TKey,TValue>Creates a Dictionary<TKey,TValue> from an IEnumerable<T> according to a specified key selector function and key comparer.

ToDictionary<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>)

根据指定的键选择器和元素选择器函数,从 IEnumerable<T> 创建一个 Dictionary<TKey,TValue>Creates a Dictionary<TKey,TValue> from an IEnumerable<T> according to specified key selector and element selector functions.

ToDictionary<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>, IEqualityComparer<TKey>)

根据指定的键选择器函数、比较器和元素选择器函数,从 IEnumerable<T> 创建一个 Dictionary<TKey,TValue>Creates a Dictionary<TKey,TValue> from an IEnumerable<T> according to a specified key selector function, a comparer, and an element selector function.

ToHashSet<TSource>(IEnumerable<TSource>)

IEnumerable<T> 创建一个 HashSet<T>Creates a HashSet<T> from an IEnumerable<T>.

ToHashSet<TSource>(IEnumerable<TSource>, IEqualityComparer<TSource>)

使用 comparer 通过 IEnumerable<T> 创建 HashSet<T>,以用于比较键。Creates a HashSet<T> from an IEnumerable<T> using the comparer to compare keys.

ToList<TSource>(IEnumerable<TSource>)

IEnumerable<T> 创建一个 List<T>Creates a List<T> from an IEnumerable<T>.

ToLookup<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)

根据指定的键选择器函数,从 IEnumerable<T> 创建一个 Lookup<TKey,TElement>Creates a Lookup<TKey,TElement> from an IEnumerable<T> according to a specified key selector function.

ToLookup<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IEqualityComparer<TKey>)

根据指定的键选择器函数和键比较器,从 IEnumerable<T> 创建一个 Lookup<TKey,TElement>Creates a Lookup<TKey,TElement> from an IEnumerable<T> according to a specified key selector function and key comparer.

ToLookup<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>)

根据指定的键选择器和元素选择器函数,从 IEnumerable<T> 创建一个 Lookup<TKey,TElement>Creates a Lookup<TKey,TElement> from an IEnumerable<T> according to specified key selector and element selector functions.

ToLookup<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>, IEqualityComparer<TKey>)

根据指定的键选择器函数、比较器和元素选择器函数,从 IEnumerable<T> 创建一个 Lookup<TKey,TElement>Creates a Lookup<TKey,TElement> from an IEnumerable<T> according to a specified key selector function, a comparer and an element selector function.

Union<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)

通过使用默认的相等比较器,生成两个序列的并集。Produces the set union of two sequences by using the default equality comparer.

Union<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>)

通过使用指定的 IEqualityComparer<T> 生成两个序列的并集。Produces the set union of two sequences by using a specified IEqualityComparer<T>.

Where<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)

基于谓词筛选值序列。Filters a sequence of values based on a predicate.

Where<TSource>(IEnumerable<TSource>, Func<TSource,Int32,Boolean>)

基于谓词筛选值序列。Filters a sequence of values based on a predicate. 将在谓词函数的逻辑中使用每个元素的索引。Each element's index is used in the logic of the predicate function.

Zip<TFirst,TSecond>(IEnumerable<TFirst>, IEnumerable<TSecond>)

使用两个指定序列中的元素生成元组序列。Produces a sequence of tuples with elements from the two specified sequences.

Zip<TFirst,TSecond,TResult>(IEnumerable<TFirst>, IEnumerable<TSecond>, Func<TFirst,TSecond,TResult>)

将指定函数应用于两个序列的对应元素,以生成结果序列。Applies a specified function to the corresponding elements of two sequences, producing a sequence of the results.

AsParallel(IEnumerable)

启用查询的并行化。Enables parallelization of a query.

AsParallel<TSource>(IEnumerable<TSource>)

启用查询的并行化。Enables parallelization of a query.

AsQueryable(IEnumerable)

IEnumerable 转换为 IQueryableConverts an IEnumerable to an IQueryable.

AsQueryable<TElement>(IEnumerable<TElement>)

将泛型 IEnumerable<T> 转换为泛型 IQueryable<T>Converts a generic IEnumerable<T> to a generic IQueryable<T>.

Ancestors<T>(IEnumerable<T>)

返回元素集合,其中包含源集合中每个节点的上级。Returns a collection of elements that contains the ancestors of every node in the source collection.

Ancestors<T>(IEnumerable<T>, XName)

返回经过筛选的元素集合,其中包含源集合中每个节点的上级。Returns a filtered collection of elements that contains the ancestors of every node in the source collection. 集合中仅包括具有匹配 XName 的元素。Only elements that have a matching XName are included in the collection.

DescendantNodes<T>(IEnumerable<T>)

返回源集合中每个文档和元素的子代节点的集合。Returns a collection of the descendant nodes of every document and element in the source collection.

Descendants<T>(IEnumerable<T>)

返回元素集合,其中包含源集合中每个元素和文档的子代元素。Returns a collection of elements that contains the descendant elements of every element and document in the source collection.

Descendants<T>(IEnumerable<T>, XName)

返回经过筛选的元素集合,其中包含源集合中每个元素和文档的子代元素。Returns a filtered collection of elements that contains the descendant elements of every element and document in the source collection. 集合中仅包括具有匹配 XName 的元素。Only elements that have a matching XName are included in the collection.

Elements<T>(IEnumerable<T>)

返回源集合中每个元素和文档的子元素的集合。Returns a collection of the child elements of every element and document in the source collection.

Elements<T>(IEnumerable<T>, XName)

返回源集合中经过筛选的每个元素和文档的子元素集合。Returns a filtered collection of the child elements of every element and document in the source collection. 集合中仅包括具有匹配 XName 的元素。Only elements that have a matching XName are included in the collection.

InDocumentOrder<T>(IEnumerable<T>)

返回节点集合(其中包含源集合中的所有节点),并按文档顺序排列。Returns a collection of nodes that contains all nodes in the source collection, sorted in document order.

Nodes<T>(IEnumerable<T>)

返回源集合中每个文档和元素的子节点集合。Returns a collection of the child nodes of every document and element in the source collection.

Remove<T>(IEnumerable<T>)

将源集合中的每个节点从其父节点中移除。Removes every node in the source collection from its parent node.

适用于

线程安全性

此类型是线程安全的。This type is thread safe.

另请参阅