This documentation is archived and is not being maintained.

IDictionary.Item Property

When implemented by a class, gets or sets the element with the specified key.

[C#] In C#, this property is the indexer for the IDictionary class.

[Visual Basic]
Default Property Item( _
   ByVal key As Object _
) As Object
object this[
   object key
] {get; set;}
__property Object* get_Item(
 Object* key
__property void set_Item(
 Object* key,
returnValue = IDictionaryObject.Item(key);
IDictionaryObject.Item(key) = returnValue;
returnValue = IDictionaryObject(key);
IDictionaryObject(key) = returnValue;

[JScript] In JScript, you can use the default indexed properties defined by a type, but you cannot explicitly define your own. However, specifying the expando attribute on a class automatically provides a default indexed property whose type is Object and whose index type is String.

Arguments [JScript]

The key of the element to get or set.

Parameters [Visual Basic, C#, C++]

The key of the element to get or set.

Property Value

The element with the specified key.


Exception Type Condition
ArgumentNullException key is a null reference (Nothing in Visual Basic).
NotSupportedException The property is set and the IDictionary is read-only.


The property is set, key does not exist in the collection, and the IDictionary has a fixed size.


This property provides the ability to access a specific element in the collection by using the following syntax: myCollection[key].

When setting this property, if the specified key already exists in the dictionary, the value is replaced; otherwise, a new element is created. In contrast, the Add method does not modify existing elements.


Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family, Common Language Infrastructure (CLI) Standard

See Also

IDictionary Interface | IDictionary Members | System.Collections Namespace | Add