Collection.Item Property (Object)

 
System_CAPS_noteNote

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Returns a specific element of a Collection object either by position or by key. Read-only.

Namespace:   Microsoft.VisualBasic
Assembly:  Microsoft.VisualBasic (in Microsoft.VisualBasic.dll)

public object this[
	object Index
] { get; }

Parameters

Index
Type: System.Object

(A) A numeric expression that specifies the position of an element of the collection. Index must be a number from 1 through the value of the collection's Count property. Or (B) An Object expression that specifies the position or key string of an element of the collection.

Property Value

Type: System.Object

Returns a specific element of a Collection object either by position or by key. Read-only.

If Index is of type Object, the Item property attempts to treat it as a String, Char, Char array, or integer value. If Item cannot convert Index to String or Integer, it throws an ArgumentException exception.

The Item property is the default property for a collection. Therefore, the following lines of code are equivalent.

MsgBox(CStr(customers.Item(1)))
MsgBox(CStr(customers(1)))

The following example uses the Item property to retrieve a reference to an object in a collection. It creates birthdays as a Collection object and then retrieves the object representing Bill's birthday, using the key "Bill" as the Index argument.

Dim birthdays As New Collection()
birthdays.Add(New DateTime(2001, 1, 12), "Bill")
birthdays.Add(New DateTime(2001, 1, 13), "Joe")
birthdays.Add(New DateTime(2001, 1, 14), "Mike")
birthdays.Add(New DateTime(2001, 1, 15), "Pete")
Dim aBirthday As DateTime
aBirthday = birthdays.Item("Bill")
MsgBox(CStr(aBirthday))
aBirthday = birthdays("Bill")
MsgBox(CStr(aBirthday))

Note that the first call explicitly specifies the Item property, but the second does not. Both calls work because the Item property is the default property for a Collection object.

.NET Framework
Available since 1.1
Silverlight
Available since 2.0
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