OrderedDictionary.Contains Method

Determines whether the OrderedDictionary collection contains a specific key.

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

abstract Contains : 
        key:Object -> bool  
override Contains : 
        key:Object -> bool


Type: System.Object

The key to locate in the OrderedDictionary collection.

Return Value

Type: System.Boolean
true if the OrderedDictionary collection contains an element with the specified key; otherwise, false.



Using the Item property can return a null value if the key does not exist or if the key is a null reference (Nothing in Visual Basic). Use the Contains method to determine if a specific key exists in the OrderedDictionary collection.

Starting with the .NET Framework 2.0, this method uses the collection’s objects’ Equals and CompareTo methods on item to determine whether item exists. In the earlier versions of the .NET Framework, this determination was made by using the Equals and CompareTo methods of the item parameter on the objects in the collection.

The following code example demonstrates the modification of an OrderedDictionary collection. In this example, the Contains method is used to determine if an entry exists before attempting to remove it. This code is part of a larger code example that can be viewed at OrderedDictionary.

No code example is currently available or this language may not be supported.

.NET Framework

Supported in: 4.5, 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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