ContainsKey Method

SortedDictionary(Of TKey, TValue).ContainsKey Method

[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]

Determines whether the SortedDictionary(Of TKey, TValue) contains an element with the specified key.

Namespace:  System.Collections.Generic
Assembly:  System (in System.dll)

'Declaration
Public Function ContainsKey ( _
	key As TKey _
) As Boolean

Parameters

key
Type: TKey
The key to locate in the SortedDictionary(Of TKey, TValue).

Return Value

Type: System.Boolean
true if the SortedDictionary(Of TKey, TValue) contains an element with the specified key; otherwise, false.

Implements

IDictionary(Of TKey, TValue).ContainsKey(TKey)

ExceptionCondition
ArgumentNullException

key is Nothing.

This method is an O(log n) operation.

The following code example shows how to use the ContainsKey method to test whether a key exists prior to calling the Add method. It also shows how to use the TryGetValue method to retrieve values, which is an efficient way to retrieve values when a program frequently tries keys that are not in the dictionary. Finally, it shows the least efficient way to test whether keys exist, by using the Item property (the indexer in C#).

This code example is part of a larger example provided for the SortedDictionary(Of TKey, TValue) class.

Windows Phone OS

Supported in: 8.1, 8.0

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