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Dictionary<TKey, TValue>.IDictionary.Remove Method

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

Removes the element with the specified key from the IDictionary.

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

Syntax

'Declaration
Private Sub Remove ( _
    key As Object _
) Implements IDictionary.Remove

void IDictionary.Remove(
    Object key
)

Parameters

Implements

IDictionary.Remove(Object)

Exceptions

Exception Condition
ArgumentNullException

key is nulla null reference (Nothing in Visual Basic).

Remarks

This method approaches an O(1) operation.

Examples

The following code example shows how to use the IDictionary.Remove of the System.Collections.IDictionary interface with a Dictionary<TKey, TValue>.

The code example is part of a larger example, including output, provided for the IDictionary.Add method.

Imports System.Collections
Imports System.Collections.Generic

Public Class Example

   Public Shared Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)

      ' Create a new dictionary of strings, with string keys,
      ' and access it using the IDictionary interface.
      '
      Dim openWith As IDictionary = _
          New Dictionary(Of String, String)

      ' Add some elements to the dictionary. There are no 
      ' duplicate keys, but some of the values are duplicates.
      ' IDictionary.Add throws an exception if incorrect types
      ' are supplied for key or value.
      openWith.Add("txt", "notepad.exe")
      openWith.Add("bmp", "paint.exe")
      openWith.Add("dib", "paint.exe")
      openWith.Add("rtf", "wordpad.exe")


...


' Use the Remove method to remove a key/value pair. No
' exception is thrown if the wrong data type is supplied.
outputBlock.Text &= vbLf + "Remove(""dib"")" & vbCrLf
openWith.Remove("dib")

If Not openWith.Contains("dib") Then
   outputBlock.Text &= "Key ""dib"" is not found." & vbCrLf
End If


...



   End Sub

End Class

using System;
using System.Collections;
using System.Collections.Generic;

public class Example
{
   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      // Create a new dictionary of strings, with string keys,
      // and access it using the IDictionary interface.
      //
      IDictionary openWith = new Dictionary<string, string>();

      // Add some elements to the dictionary. There are no 
      // duplicate keys, but some of the values are duplicates.
      // IDictionary.Add throws an exception if incorrect types
      // are supplied for key or value.
      openWith.Add("txt", "notepad.exe");
      openWith.Add("bmp", "paint.exe");
      openWith.Add("dib", "paint.exe");
      openWith.Add("rtf", "wordpad.exe");


...


// Use the Remove method to remove a key/value pair. No
// exception is thrown if the wrong data type is supplied.
outputBlock.Text += "\nRemove(\"dib\")" + "\n";
openWith.Remove("dib");

if (!openWith.Contains("dib"))
{
   outputBlock.Text += "Key \"dib\" is not found." + "\n";
}


...


   }
}

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.