IDictionary.Remove Method

Dictionary<TKey, TValue>.IDictionary.Remove Method

[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]

Removes the element with the specified key from the IDictionary.

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

void IDictionary.Remove(
	Object key


Type: System.Object
The key of the element to remove.




key is null.

This method approaches an O(1) operation.

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.

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";

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



Windows Phone OS

Supported in: 8.1, 8.0, 7.1, 7.0

Windows Phone

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