DictionaryExtensionsAddOrUpdateTKey, TValue(IDictionaryTKey, TValue, TKey, TValue, FuncTKey, TValue, TValue) Method

Adds a key/value pair to the dictionary if the key does not already exist, or updates a key/value pair in the dictionary by using the specified updateValueFactory if the key already exists. The operation is thread safe if dictionary is a ThreadSafeDictionaryTKey, TValue, ConcurrentDictionaryTKey, TValue or LockingDictionaryTKey, TValue instance. For other IDictionaryTKey, TValue implementations the caller should care about thread safety if needed.

Definition

Namespace: KGySoft.CoreLibraries
Assembly: KGySoft.CoreLibraries (in KGySoft.CoreLibraries.dll) Version: 9.0.0

C#

public static TValue AddOrUpdate<TKey, TValue>(
	this IDictionary<TKey, TValue> dictionary,
	TKey key,
	TValue addValue,
	Func<TKey, TValue, TValue> updateValueFactory
)

VB

<ExtensionAttribute>
Public Shared Function AddOrUpdate(Of TKey, TValue) ( 
	dictionary As IDictionary(Of TKey, TValue),
	key As TKey,
	addValue As TValue,
	updateValueFactory As Func(Of TKey, TValue, TValue)
) As TValue

C++

public:
[ExtensionAttribute]
generic<typename TKey, typename TValue>
static TValue AddOrUpdate(
	IDictionary<TKey, TValue>^ dictionary, 
	TKey key, 
	TValue addValue, 
	Func<TKey, TValue, TValue>^ updateValueFactory
)

F#

[<ExtensionAttribute>]
static member AddOrUpdate : 
        dictionary : IDictionary<'TKey, 'TValue> * 
        key : 'TKey * 
        addValue : 'TValue * 
        updateValueFactory : Func<'TKey, 'TValue, 'TValue> -> 'TValue

Parameters

dictionary IDictionaryTKey, TValue: The target dictionary.
key TKey: The key to be added or whose value should be updated.
addValue TValue: The value to be added for an absent key.
updateValueFactory FuncTKey, TValue, TValue: A delegate used to generate a new value for an existing key based on the key's existing value.

Type Parameters

TKey: The type of the keys in the dictionary.
TValue: The type of the values in the dictionary.

Return Value

TValue
The new value for the key. This will be either addValue (if the key was absent) or the result of updateValueFactory (if the key was present).

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type IDictionaryTKey, TValue. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).

Exceptions

ArgumentNullException	dictionary, key or updateValueFactory is .
NotSupportedException	dictionary is read-only.