Item Property

2013-01-16

[This documentation is for preview only, and is subject to change in later releases. Blank topics are included as placeholders.]

Gets or sets the value associated with the specified key.

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

Syntax

'Declaration
Public Property Item ( _
    key As Object _
) As Object

public Object this[
    Object key
] { get; set; }

public:
virtual property Object^ Item[Object^ key] {
    Object^ get (Object^ key) sealed;
    void set (Object^ key, Object^ value) sealed;
}

abstract Item : 
        key:Object -> Object with get, set
override Item : 
        key:Object -> Object with get, set

JScript does not support indexed properties.

Parameters

key
Type: System. . :: . .Object
The key whose value to get or set.

Property Value

Type: System. . :: . .Object
The value associated with the specified key. If the specified key is not found, attempting to get it returns nullNothingnullptrunita null reference (Nothing in Visual Basic), and attempting to set it creates a new element using the specified key.

Implements

IDictionary. . :: . .Item

Remarks

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

You can also use the Item property to add new elements by setting the value of a key that does not exist in the Hashtable; for example, myCollection["myNonexistentKey"] = myValue. However, if the specified key already exists in the Hashtable, setting the Item property overwrites the old value. In contrast, the Add method does not modify existing elements.

A key cannot be null Nothing nullptr unit a null reference (Nothing in Visual Basic) , but a value can be. To distinguish between null Nothing nullptr unit a null reference (Nothing in Visual Basic) that is returned because the specified key is not found and null Nothing nullptr unit a null reference (Nothing in Visual Basic) that is returned because the value of the specified key is null Nothing nullptr unit a null reference (Nothing in Visual Basic) , use the Contains method or the ContainsKey method to determine if the key exists in the list.

Retrieving the value of this property is an O(1) operation; setting the property is also an O(1) operation.

.NET Framework Security

Full trust for the immediate caller. This member cannot be used by partially trusted code. For more information, see dd66cd4c-b087-415f-9c3e-94e3a1835f74.

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