Article
11/18/2011

IDictionary.Keys Property

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Gets an ICollection object containing the keys of the IDictionary object.

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

Syntax

'Declaration
ReadOnly Property Keys As ICollection

ICollection Keys { get; }

Property Value

Type: System.Collections.ICollection
An ICollection object containing the keys of the IDictionary object.

Remarks

The order of the keys in the returned ICollection object is unspecified, but is guaranteed to be the same order as the corresponding values in the ICollection returned by the Values property.

Examples

The following code example demonstrates how to implement the Keys property. This code example is part of a larger example provided for the IDictionary class.

Public ReadOnly Property Keys() As ICollection Implements IDictionary.Keys
   Get

      ' Return an array where each item is a key.
      ' Note: Declaring keyArray() to have a size of ItemsInUse - 1
      '       ensures that the array is properly sized, in VB.NET
      '       declaring an array of size N creates an array with
      '       0 through N elements, including N, as opposed to N - 1
      '       which is the default behavior in C# and C++.
      Dim keyArray() As Object = New Object(ItemsInUse - 1) {}
      Dim n As Integer
      For n = 0 To ItemsInUse - 1
         keyArray(n) = items(n).Key
      Next n

      Return keyArray
   End Get
End Property

public ICollection Keys
{
   get
   {
      // Return an array where each item is a key.
      Object[] keys = new Object[ItemsInUse];
      for (Int32 n = 0; n < ItemsInUse; n++)
         keys[n] = items[n].Key;
      return keys;
   }
}

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

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