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ConcurrentDictionary<TKey,TValue>.AddOrUpdate 方法

  • 参考

定义

命名空间:
System.Collections.Concurrent
程序集:
System.Collections.Concurrent.dll
程序集:
mscorlib.dll
程序集:
netstandard.dll

如果该键不存在，则将键/值对添加到 ConcurrentDictionary<TKey,TValue> 中；如果该键已经存在，则更新 ConcurrentDictionary<TKey,TValue> 中的键/值对。

重载

AddOrUpdate(TKey, Func<TKey,TValue>, Func<TKey,TValue,TValue>)

如果该键不存在，则使用指定函数将键/值对添加到 ConcurrentDictionary<TKey,TValue>；如果该键已存在，则使用该函数更新 ConcurrentDictionary<TKey,TValue> 中的键/值对。
AddOrUpdate(TKey, TValue, Func<TKey,TValue,TValue>)

如果该键不存在，则将键/值对添加到 ConcurrentDictionary<TKey,TValue> 中；如果该键已经存在，则通过使用指定的函数更新 ConcurrentDictionary<TKey,TValue> 中的键/值对。
AddOrUpdate<TArg>(TKey, Func<TKey,TArg,TValue>, Func<TKey,TValue,TArg,TValue>, TArg)

使用指定函数和参数将键/值对添加到 ConcurrentDictionary<TKey,TValue>中（若尚无键）；或使用指定函数和参数更新 ConcurrentDictionary<TKey,TValue> 中的键/值对（若已有键）。

示例

以下示例演示如何调用 AddOrUpdate 方法：

class CD_GetOrAddOrUpdate
{
    // Demonstrates:
    //      ConcurrentDictionary<TKey, TValue>.AddOrUpdate()
    //      ConcurrentDictionary<TKey, TValue>.GetOrAdd()
    //      ConcurrentDictionary<TKey, TValue>[]
    static void Main()
    {
        // Construct a ConcurrentDictionary
        ConcurrentDictionary<int, int> cd = new ConcurrentDictionary<int, int>();

        // Bombard the ConcurrentDictionary with 10000 competing AddOrUpdates
        Parallel.For(0, 10000, i =>
        {
            // Initial call will set cd[1] = 1.
            // Ensuing calls will set cd[1] = cd[1] + 1
            cd.AddOrUpdate(1, 1, (key, oldValue) => oldValue + 1);
        });

        Console.WriteLine("After 10000 AddOrUpdates, cd[1] = {0}, should be 10000", cd[1]);

        // Should return 100, as key 2 is not yet in the dictionary
        int value = cd.GetOrAdd(2, (key) => 100);
        Console.WriteLine("After initial GetOrAdd, cd[2] = {0} (should be 100)", value);

        // Should return 100, as key 2 is already set to that value
        value = cd.GetOrAdd(2, 10000);
        Console.WriteLine("After second GetOrAdd, cd[2] = {0} (should be 100)", value);
    }
}

// Demonstrates:
//      ConcurrentDictionary<TKey, TValue>.AddOrUpdate()
//      ConcurrentDictionary<TKey, TValue>.GetOrAdd()
//      ConcurrentDictionary<TKey, TValue>[]

// Construct a ConcurrentDictionary
let cd = ConcurrentDictionary<int, int>()

// Bombard the ConcurrentDictionary with 10000 competing AddOrUpdates
Parallel.For(
    0,
    10000,
    fun i ->

        // Initial call will set cd[1] = 1.
        // Ensuing calls will set cd[1] = cd[1] + 1
        cd.AddOrUpdate(1, 1, (fun key oldValue -> oldValue + 1)) |> ignore
)
|> ignore

printfn $"After 10000 AddOrUpdates, cd[1] = {cd[1]}, should be 10000"

// Should return 100, as key 2 is not yet in the dictionary
let value = cd.GetOrAdd(2, (fun key -> 100))
printfn $"After initial GetOrAdd, cd[2] = {value} (should be 100)"

// Should return 100, as key 2 is already set to that value2
let value2 = cd.GetOrAdd(2, 10000)
printfn $"After second GetOrAdd, cd[2] = {value2} (should be 100)"

' Imports System.Collections.Concurrent
' Imports System.Threading.Tasks

Class CD_GetOrAddOrUpdate

    ' Demonstrates:
    ' ConcurrentDictionary<TKey, TValue>.AddOrUpdate()
    ' ConcurrentDictionary<TKey, TValue>.GetOrAdd()
    ' ConcurrentDictionary<TKey, TValue>[]
    Shared Sub Main()
        ' Construct a ConcurrentDictionary
        Dim cd As New ConcurrentDictionary(Of Integer, Integer)()

        ' Bombard the ConcurrentDictionary with 10000 competing AddOrUpdates
        Parallel.For(0, 10000,
                       Sub(i)
                           ' Initial call will set cd[1] = 1. 
                           ' Ensuing calls will set cd[1] = cd[1] + 1
                           cd.AddOrUpdate(1, 1, Function(key, oldValue) oldValue + 1)
                       End Sub)

        Console.WriteLine("After 10000 AddOrUpdates, cd[1] = {0}, should be 10000", cd(1))

        ' Should return 100, as key 2 is not yet in the dictionary
        Dim value As Integer = cd.GetOrAdd(2, Function(key) 100)
        Console.WriteLine("After initial GetOrAdd, cd[2] = {0} (should be 100)", value)

        ' Should return 100, as key 2 is already set to that value
        value = cd.GetOrAdd(2, 10000)
        Console.WriteLine("After second GetOrAdd, cd[2] = {0} (should be 100)", value)
    End Sub
End Class

AddOrUpdate(TKey, Func<TKey,TValue>, Func<TKey,TValue,TValue>)

Source:
ConcurrentDictionary.cs
Source:
ConcurrentDictionary.cs
Source:
ConcurrentDictionary.cs

如果该键不存在，则使用指定函数将键/值对添加到 ConcurrentDictionary<TKey,TValue>；如果该键已存在，则使用该函数更新 ConcurrentDictionary<TKey,TValue> 中的键/值对。

public:
 TValue AddOrUpdate(TKey key, Func<TKey, TValue> ^ addValueFactory, Func<TKey, TValue, TValue> ^ updateValueFactory);
public TValue AddOrUpdate (TKey key, Func<TKey,TValue> addValueFactory, Func<TKey,TValue,TValue> updateValueFactory);
member this.AddOrUpdate : 'Key * Func<'Key, 'Value> * Func<'Key, 'Value, 'Value> -> 'Value
Public Function AddOrUpdate (key As TKey, addValueFactory As Func(Of TKey, TValue), updateValueFactory As Func(Of TKey, TValue, TValue)) As TValue

参数

key
TKey

要添加的键或应更新其值的键。

addValueFactory
Func<TKey,TValue>

用于为空缺键生成值的函数。

updateValueFactory
Func<TKey,TValue,TValue>

用以基于键的现有值为现有键生成新值的函数。

返回

TValue

键的新值。 这将为 addValueFactory 的结果（若没有键）或 updateValueFactory 的结果（若有键）。

例外

ArgumentNullException

key、addValueFactory 或 updateValueFactory 为 null。

OverflowException

字典包含过多元素。

注解

如果同时在不同的线程上调用 AddOrUpdate ， addValueFactory 可能会多次调用，但其键/值对可能不会添加到每个调用的字典中。

对于对字典的修改和写入操作， ConcurrentDictionary<TKey,TValue> 请使用细粒度锁定来确保线程安全 (字典上的读取操作以无锁方式执行) 。 addValueFactory可以多次执行 和 updateValueFactory 委托，以验证值是否已按预期添加或更新。 但是，在锁外调用它们，以避免在锁下执行未知代码时可能出现的问题。 因此， AddOrUpdate 对于 类上的所有其他操作而言， 不是原子的 ConcurrentDictionary<TKey,TValue> 。

另请参阅

适用于

AddOrUpdate(TKey, TValue, Func<TKey,TValue,TValue>)

Source:
ConcurrentDictionary.cs
Source:
ConcurrentDictionary.cs
Source:
ConcurrentDictionary.cs

如果该键不存在，则将键/值对添加到 ConcurrentDictionary<TKey,TValue> 中；如果该键已经存在，则通过使用指定的函数更新 ConcurrentDictionary<TKey,TValue> 中的键/值对。

public:
 TValue AddOrUpdate(TKey key, TValue addValue, Func<TKey, TValue, TValue> ^ updateValueFactory);
public TValue AddOrUpdate (TKey key, TValue addValue, Func<TKey,TValue,TValue> updateValueFactory);
member this.AddOrUpdate : 'Key * 'Value * Func<'Key, 'Value, 'Value> -> 'Value
Public Function AddOrUpdate (key As TKey, addValue As TValue, updateValueFactory As Func(Of TKey, TValue, TValue)) As TValue

参数

key
TKey

要添加的键或应更新其值的键。

addValue
TValue

要为缺席键添加的值。

updateValueFactory
Func<TKey,TValue,TValue>

用以基于键的现有值为现有键生成新值的函数。

返回

TValue

键的新值。 这将为 addValue （若没有键）或 updateValueFactory 的结果（若有键）。

例外

ArgumentNullException

key 或 updateValueFactory 为 null。

OverflowException

字典包含过多元素。

示例

以下示例代码演示如何初始化 ConcurrentDictionary<TKey,TValue> 以及如何使用 AddOrUpdate 方法向集合添加附加项并更新现有项。

using System;
using System.Collections.Concurrent;

class CD_Ctor
{
    // Demonstrates:
    //      ConcurrentDictionary<TKey, TValue> ctor(concurrencyLevel, initialCapacity)
    //      ConcurrentDictionary<TKey, TValue>[TKey]
    static void Main()
    {
        // We know how many items we want to insert into the ConcurrentDictionary.
        // So set the initial capacity to some prime number above that, to ensure that
        // the ConcurrentDictionary does not need to be resized while initializing it.
        int HIGHNUMBER = 64;
        int initialCapacity = 101;

        // The higher the concurrencyLevel, the higher the theoretical number of operations
        // that could be performed concurrently on the ConcurrentDictionary.  However, global
        // operations like resizing the dictionary take longer as the concurrencyLevel rises.
        // For the purposes of this example, we'll compromise at numCores * 2.
        int numProcs = Environment.ProcessorCount;
        int concurrencyLevel = numProcs * 2;

        // Construct the dictionary with the desired concurrencyLevel and initialCapacity
        ConcurrentDictionary<int, int> cd = new ConcurrentDictionary<int, int>(concurrencyLevel, initialCapacity);

        // Initialize the dictionary
        for (int i = 1; i <= HIGHNUMBER; i++) cd[i] = i * i;

        Console.WriteLine("The square of 23 is {0} (should be {1})", cd[23], 23 * 23);

        // Now iterate through, adding one to the end of the list. Existing items should be updated to be divided by their
        // key  and a new item will be added that is the square of its key.
        for (int i = 1; i <= HIGHNUMBER + 1; i++)
          cd.AddOrUpdate(i, i * i, (k,v) => v / i);

        Console.WriteLine("The square root of 529 is {0} (should be {1})", cd[23], 529 / 23);
        Console.WriteLine("The square of 65 is {0} (should be {1})", cd[HIGHNUMBER + 1], ((HIGHNUMBER + 1) * (HIGHNUMBER + 1)));
    }
}

open System
open System.Collections.Concurrent

// Demonstrates:
//      ConcurrentDictionary<TKey, TValue> ctor(concurrencyLevel, initialCapacity)
//      ConcurrentDictionary<TKey, TValue>[TKey]

// We know how many items we want to insert into the ConcurrentDictionary.
// So set the initial capacity to some prime number above that, to ensure that
// the ConcurrentDictionary does not need to be resized while initializing it.
let HIGHNUMBER = 64
let initialCapacity = 101

// The higher the concurrencyLevel, the higher the theoretical number of operations
// that could be performed concurrently on the ConcurrentDictionary.  However, global
// operations like resizing the dictionary take longer as the concurrencyLevel rises.
// For the purposes of this example, we'll compromise at numCores * 2.
let numProcs = Environment.ProcessorCount
let concurrencyLevel = numProcs * 2

// Construct the dictionary with the desired concurrencyLevel and initialCapacity
let cd = ConcurrentDictionary<int, int>(concurrencyLevel, initialCapacity)

// Initialize the dictionary
for i = 1 to HIGHNUMBER do
    cd[i] <- i * i

printfn $"The square of 23 is {cd[23]} (should be {23 * 23})"

// Now iterate through, adding one to the end of the list. Existing items should be updated to be divided by their
// key  and a new item will be added that is the square of its key.
for i = 1 to HIGHNUMBER + 1 do
    cd.AddOrUpdate(i, i * i, (fun k v -> v / i)) |> ignore

printfn $"The square root of 529 is {cd[23]} (should be {529 / 23})"
printfn $"The square of 65 is {cd[HIGHNUMBER + 1]} (should be {(HIGHNUMBER + 1) * (HIGHNUMBER + 1)})"

Imports System.Collections.Concurrent

Class CD_Ctor
    ' Demonstrates: 
    '      ConcurrentDictionary<TKey, TValue> ctor(concurrencyLevel, initialCapacity) 
    '      ConcurrentDictionary<TKey, TValue>[TKey] 
    Public Shared Sub Main()
        ' We know how many items we want to insert into the ConcurrentDictionary. 
        ' So set the initial capacity to some prime number above that, to ensure that 
        ' the ConcurrentDictionary does not need to be resized while initializing it. 
        Dim HIGHNUMBER As Integer = 64
        Dim initialCapacity As Integer = 101

        ' The higher the concurrencyLevel, the higher the theoretical number of operations 
        ' that could be performed concurrently on the ConcurrentDictionary.  However, global 
        ' operations like resizing the dictionary take longer as the concurrencyLevel rises.  
        ' For the purposes of this example, we'll compromise at numCores * 2. 
        Dim numProcs As Integer = Environment.ProcessorCount
        Dim concurrencyLevel As Integer = numProcs * 2

        ' Construct the dictionary with the desired concurrencyLevel and initialCapacity
        Dim cd As New ConcurrentDictionary(Of Integer, Integer)(concurrencyLevel, initialCapacity)

        ' Initialize the dictionary 
        For i As Integer = 1 To HIGHNUMBER
            cd(i) = i * i
        Next

        Console.WriteLine("The square of 23 is {0} (should be {1})", cd(23), 23 * 23)

        ' Now iterate through, adding one to the end of the list. Existing items should be updated to be divided by their 
        ' key  and a new item will be added that is the square of its key.
        For i As Integer = 1 To HIGHNUMBER + 1

            cd.AddOrUpdate(i, i * i, Function(k, v)
                                         Return v / i
                                     End Function)
        Next

        Console.WriteLine("The square root of 529 is {0} (should be {1})", cd(23), 529 / 23)
        Console.WriteLine("The square of 65 is {0} (should be {1})", cd(HIGHNUMBER + 1), ((HIGHNUMBER + 1) * (HIGHNUMBER + 1)))

    End Sub
End Class

对于对字典的修改和写入操作， ConcurrentDictionary<TKey,TValue> 请使用精细锁定来确保线程安全。 (字典上的读取操作以无锁方式执行。) addValueFactory 可以多次执行 和 updateValueFactory 委托，以验证值是否已按预期添加或更新。 但是，在锁外调用它们，以避免在锁下执行未知代码时可能出现的问题。 因此， AddOrUpdate 对于 类上的所有其他操作而言， 不是原子的 ConcurrentDictionary<TKey,TValue> 。

另请参阅

适用于

AddOrUpdate<TArg>(TKey, Func<TKey,TArg,TValue>, Func<TKey,TValue,TArg,TValue>, TArg)

Source:
ConcurrentDictionary.cs
Source:
ConcurrentDictionary.cs
Source:
ConcurrentDictionary.cs

使用指定函数和参数将键/值对添加到 ConcurrentDictionary<TKey,TValue>中（若尚无键）；或使用指定函数和参数更新 ConcurrentDictionary<TKey,TValue> 中的键/值对（若已有键）。

public:
generic <typename TArg>
 TValue AddOrUpdate(TKey key, Func<TKey, TArg, TValue> ^ addValueFactory, Func<TKey, TValue, TArg, TValue> ^ updateValueFactory, TArg factoryArgument);
public TValue AddOrUpdate<TArg> (TKey key, Func<TKey,TArg,TValue> addValueFactory, Func<TKey,TValue,TArg,TValue> updateValueFactory, TArg factoryArgument);
member this.AddOrUpdate : 'Key * Func<'Key, 'Arg, 'Value> * Func<'Key, 'Value, 'Arg, 'Value> * 'Arg -> 'Value
Public Function AddOrUpdate(Of TArg) (key As TKey, addValueFactory As Func(Of TKey, TArg, TValue), updateValueFactory As Func(Of TKey, TValue, TArg, TValue), factoryArgument As TArg) As TValue

类型参数

TArg

要传入 addValueFactory 和 updateValueFactory的参数的类型。

参数

key
TKey

要添加的键或应更新其值的键。

addValueFactory
Func<TKey,TArg,TValue>

用于为空缺键生成值的函数。

updateValueFactory
Func<TKey,TValue,TArg,TValue>

用以基于键的现有值为现有键生成新值的函数。

factoryArgument
TArg

要传入 addValueFactory 和 updateValueFactory 的参数。

返回

TValue

键的新值。 这将为 addValueFactory 的结果（若没有键）或 updateValueFactory 的结果（若有键）。

例外

ArgumentNullException

key、addValueFactory 或 updateValueFactory 为空引用（在 Visual Basic 中为 Nothing）。

OverflowException

字典包含过多元素。

注解

如果同时在不同的线程上调用 AddOrUpdate ， addValueFactory 可能会多次调用，但其键/值对可能不会添加到每个调用的字典中。

对于对字典的修改和写入操作， ConcurrentDictionary<TKey,TValue> 请使用精细锁定来确保线程安全。 (字典上的读取操作以无锁方式执行。) addValueFactory 可以多次执行 和 updateValueFactory 委托，以验证值是否已按预期添加或更新。 但是，在锁外调用它们，以避免在锁下执行未知代码时可能出现的问题。 因此， AddOrUpdate 对于 类上的所有其他操作而言， 不是原子的 ConcurrentDictionary<TKey,TValue> 。

适用于