ConcurrentDictionary<TKey,TValue>.AddOrUpdate 方法

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

參數

傳回

TValue

索引鍵的新值。The new value for the key. 這個值會是 addValueFactory (如果索引鍵不存在) 的結果或 updateValueFactory (如果索引鍵存在) 的結果。This will be either be the result of addValueFactory (if the key was absent) or the result of updateValueFactory (if the key was present).

例外狀況

備註

如果您 AddOrUpdate 在不同的執行緒上同時呼叫，可能會呼叫 addValueFactory 多次，但是它的索引鍵/值組可能不會加入至字典中的每個呼叫。If you call AddOrUpdate simultaneously on different threads, addValueFactory may be called multiple times, but its key/value pair might not be added to the dictionary for every call.

針對字典的修改和寫入作業，會 ConcurrentDictionary<TKey,TValue> 使用細微的鎖定來確保執行緒安全。For modifications and write operations to the dictionary, ConcurrentDictionary<TKey,TValue> uses fine-grained locking to ensure thread safety. 字典的 (讀取作業會以無鎖定的方式執行。 ) 不過， addValueFactory 和 updateValueFactory 委派會在鎖定之外呼叫，以避免在鎖定下執行未知程式碼時可能發生的問題。(Read operations on the dictionary are performed in a lock-free manner.) However, the addValueFactory and updateValueFactory delegates are called outside the locks to avoid the problems that can arise from executing unknown code under a lock. 因此，對 AddOrUpdate 類別上的所有其他作業而言，不是不可部分完成的 ConcurrentDictionary<TKey,TValue> 。Therefore, AddOrUpdate is not atomic with regards to all other operations on the ConcurrentDictionary<TKey,TValue> class.

另請參閱

• 安全執行緒集合Thread-Safe Collections
• 作法：在 ConcurrentDictionary 中新增和移除項目How to: Add and Remove Items from a ConcurrentDictionary

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

參數

傳回

TValue

索引鍵的新值。The new value for the key. 這個值會是 addValue (如果索引鍵不存在) 或 updateValueFactory (如果索引鍵存在) 的結果。This will be either be addValue (if the key was absent) or the result of updateValueFactory (if the key was present).

例外狀況

範例

下列程式碼範例示範如何初始化 ConcurrentDictionary<TKey,TValue> ，以及如何使用 >addorupdate 方法將其他專案加入至集合，以及更新現有的專案。The following code example shows how to initialize an ConcurrentDictionary<TKey,TValue> and how to use the AddOrUpdate method to add an additional item to the collection, and update the existing items.

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)));
    }
}

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

針對字典的修改和寫入作業，會 ConcurrentDictionary<TKey,TValue> 使用細微的鎖定來確保執行緒安全。For modifications and write operations to the dictionary, ConcurrentDictionary<TKey,TValue> uses fine-grained locking to ensure thread safety. 字典的 (讀取作業會以無鎖定的方式執行。 ) 不過， updateValueFactory 委派會在鎖定之外呼叫，以避免在鎖定下執行未知程式碼時可能發生的問題。(Read operations on the dictionary are performed in a lock-free manner.) However, the updateValueFactory delegate is called outside the locks to avoid the problems that can arise from executing unknown code under a lock. 因此，對 AddOrUpdate 類別上的所有其他作業而言，不是不可部分完成的 ConcurrentDictionary<TKey,TValue> 。Therefore, AddOrUpdate is not atomic with regards to all other operations on the ConcurrentDictionary<TKey,TValue> class.

另請參閱

• 安全執行緒集合Thread-Safe Collections
• 作法：在 ConcurrentDictionary 中新增和移除項目How to: Add and Remove Items from a ConcurrentDictionary

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

類型參數

參數

傳回

TValue

索引鍵的新值。The new value for the key. 這個值會是 addValueFactory (如果索引鍵不存在) 的結果或 updateValueFactory (如果索引鍵存在) 的結果。This will be either be the result of addValueFactory (if the key was absent) or the result of updateValueFactory (if the key was present).

例外狀況

備註

如果您 AddOrUpdate 在不同的執行緒上同時呼叫，可能會呼叫 addValueFactory 多次，但是它的索引鍵/值組可能不會加入至字典中的每個呼叫。If you call AddOrUpdate simultaneously on different threads, addValueFactory may be called multiple times, but its key/value pair might not be added to the dictionary for every call.

針對字典的修改和寫入作業，會 ConcurrentDictionary<TKey,TValue> 使用細微的鎖定來確保執行緒安全。For modifications and write operations to the dictionary, ConcurrentDictionary<TKey,TValue> uses fine-grained locking to ensure thread safety. 字典的 (讀取作業會以無鎖定的方式執行。 ) 不過， addValueFactory 和 updateValueFactory 委派會在鎖定之外呼叫，以避免在鎖定下執行未知程式碼時可能發生的問題。(Read operations on the dictionary are performed in a lock-free manner.) However, the addValueFactory and updateValueFactory delegates are called outside the locks to avoid the problems that can arise from executing unknown code under a lock. 因此，對 AddOrUpdate 類別上的所有其他作業而言，不是不可部分完成的 ConcurrentDictionary<TKey,TValue> 。Therefore, AddOrUpdate is not atomic with regards to all other operations on the ConcurrentDictionary<TKey,TValue> class.