ConcurrentDictionary<TKey, TValue>.GetOrAdd Method (TKey, TValue)

.NET Framework (current version)

Adds a key/value pair to the ConcurrentDictionary<TKey, TValue> if the key does not already exist.

Namespace:   System.Collections.Concurrent
Assembly:  mscorlib (in mscorlib.dll)

public TValue GetOrAdd(
	TKey key,
	TValue value


Type: TKey

The key of the element to add.

Type: TValue

the value to be added, if the key does not already exist

Return Value

Type: TValue

The value for the key. This will be either the existing value for the key if the key is already in the dictionary, or the new value if the key was not in the dictionary.

Exception Condition

key is null.


The dictionary already contains the maximum number of elements (MaxValue).

Universal Windows Platform
Available since 8
.NET Framework
Available since 4.0
Portable Class Library
Supported in: portable .NET platforms
Windows Phone
Available since 8.1
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