ConcurrentDictionary<TKey,TValue>.AddOrUpdate 方法
定義
如果索引鍵不存在,則將索引鍵/值組加入 ConcurrentDictionary<TKey,TValue>,如果索引鍵存在,則更新 ConcurrentDictionary<TKey,TValue> 中的索引鍵/值組。Adds a key/value pair to the ConcurrentDictionary<TKey,TValue> if the key does not already exist, or updates a key/value pair in the ConcurrentDictionary<TKey,TValue> if the key already exists.
多載
AddOrUpdate(TKey, Func<TKey,TValue>, Func<TKey,TValue,TValue>) |
如果索引鍵不存在,則使用指定的函式將索引鍵/值組加入至 ConcurrentDictionary<TKey,TValue>,如果索引鍵存在,則更新 ConcurrentDictionary<TKey,TValue> 中的索引鍵/值組。Uses the specified functions to add a key/value pair to the ConcurrentDictionary<TKey,TValue> if the key does not already exist, or to update a key/value pair in the ConcurrentDictionary<TKey,TValue> if the key already exists. |
AddOrUpdate(TKey, TValue, Func<TKey,TValue,TValue>) |
如果索引鍵不存在,則將索引鍵/值組加入至 ConcurrentDictionary<TKey,TValue>,如果索引鍵存在,則使用指定的函式,更新 ConcurrentDictionary<TKey,TValue> 中的索引鍵/值組。Adds a key/value pair to the ConcurrentDictionary<TKey,TValue> if the key does not already exist, or updates a key/value pair in the ConcurrentDictionary<TKey,TValue> by using the specified function if the key already exists. |
AddOrUpdate<TArg>(TKey, Func<TKey,TArg,TValue>, Func<TKey,TValue,TArg,TValue>, TArg) |
若機碼不存在,使用指定的函式與引數將機碼/值組新增到 ConcurrentDictionary<TKey,TValue>,或若機碼存在,更新 ConcurrentDictionary<TKey,TValue> 中的機碼/值組。Uses the specified functions and argument to add a key/value pair to the ConcurrentDictionary<TKey,TValue> if the key does not already exist, or to update a key/value pair in the ConcurrentDictionary<TKey,TValue> if the key already exists. |
範例
下列範例顯示如何呼叫 AddOrUpdate 方法:The following example shows how to call the AddOrUpdate method:
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);
}
}
' 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>)
如果索引鍵不存在,則使用指定的函式將索引鍵/值組加入至 ConcurrentDictionary<TKey,TValue>,如果索引鍵存在,則更新 ConcurrentDictionary<TKey,TValue> 中的索引鍵/值組。Uses the specified functions to add a key/value pair to the ConcurrentDictionary<TKey,TValue> if the key does not already exist, or to update a key/value pair in the ConcurrentDictionary<TKey,TValue> if the key already exists.
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
- key
- TKey
要加入或應該更新其值的索引鍵。The key to be added or whose value should be updated
- addValueFactory
- Func<TKey,TValue>
用來為不存在的索引鍵產生值的函式。The function used to generate a value for an absent key
- updateValueFactory
- Func<TKey,TValue,TValue>
函式,用來根據索引鍵的現有值為現有索引鍵產生新值。The function used to generate a new value for an existing key based on the key's existing value
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
key
、addValueFactory
或 updateValueFactory
為 null
。key
, addValueFactory
, or updateValueFactory
is null
.
目錄包含太多項目。The dictionary contains too many elements.
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
適用於
AddOrUpdate(TKey, TValue, Func<TKey,TValue,TValue>)
如果索引鍵不存在,則將索引鍵/值組加入至 ConcurrentDictionary<TKey,TValue>,如果索引鍵存在,則使用指定的函式,更新 ConcurrentDictionary<TKey,TValue> 中的索引鍵/值組。Adds a key/value pair to the ConcurrentDictionary<TKey,TValue> if the key does not already exist, or updates a key/value pair in the ConcurrentDictionary<TKey,TValue> by using the specified function if the key already exists.
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
- key
- TKey
要加入或應該更新其值的索引鍵。The key to be added or whose value should be updated
- addValue
- TValue
要為不存在的索引鍵加入的值。The value to be added for an absent key
- updateValueFactory
- Func<TKey,TValue,TValue>
函式,用來根據索引鍵的現有值為現有索引鍵產生新值。The function used to generate a new value for an existing key based on the key's existing value
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
key
或 updateValueFactory
為 null
。key
or updateValueFactory
is null
.
目錄包含太多項目。The dictionary contains too many elements.
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
適用於
AddOrUpdate<TArg>(TKey, Func<TKey,TArg,TValue>, Func<TKey,TValue,TArg,TValue>, TArg)
若機碼不存在,使用指定的函式與引數將機碼/值組新增到 ConcurrentDictionary<TKey,TValue>,或若機碼存在,更新 ConcurrentDictionary<TKey,TValue> 中的機碼/值組。Uses the specified functions and argument to add a key/value pair to the ConcurrentDictionary<TKey,TValue> if the key does not already exist, or to update a key/value pair in the ConcurrentDictionary<TKey,TValue> if the key already exists.
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
- TArg
要傳遞至 and 的引數型 addValueFactory
別 updateValueFactory
。The type of an argument to pass into addValueFactory
and updateValueFactory
.
參數
- key
- TKey
要新增或應該更新其值的索引鍵。The key to be added or whose value should be updated.
- addValueFactory
- Func<TKey,TArg,TValue>
用來為不存在之索引鍵產生值的函式。The function used to generate a value for an absent key.
- updateValueFactory
- Func<TKey,TValue,TArg,TValue>
用來根據索引鍵之現有值為現有索引鍵產生新值的函式。The function used to generate a new value for an existing key based on the key's existing value.
- factoryArgument
- TArg
要傳入 addValueFactory
和 updateValueFactory
的引數。An argument to pass into addValueFactory
and updateValueFactory
.
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
key
、addValueFactory
或 updateValueFactory
為 Null 參考 (在 Visual Basic 中為 Nothing)。key
, addValueFactory
, or updateValueFactory
is a null reference (Nothing in Visual Basic).
目錄包含太多項目。The dictionary contains too many elements.
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.