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Dictionary<TKey, TValue>.ICollection<KeyValuePair<TKey, TValue>>.Remove Method

Removes a key and value from the dictionary.

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

bool ICollection<KeyValuePair<TKey, TValue>>.Remove(
	KeyValuePair<TKey, TValue> keyValuePair
)

Parameters

keyValuePair
Type: System.Collections.Generic.KeyValuePair<TKey, TValue>

The KeyValuePair<TKey, TValue> structure representing the key and value to remove from the Dictionary<TKey, TValue>.

Return Value

Type: System.Boolean
true if the key and value represented by keyValuePair is successfully found and removed; otherwise, false. This method returns false if keyValuePair is not found in the ICollection<T>.

Implements

ICollection<T>.Remove(T)

This method uses Comparer to determine equality for the key, and the default equality comparer EqualityComparer<T>.Default to determine equality for the value.

This method approaches an O(1) operation.

The following example shows how to use the ICollection<KeyValuePair<TKey, TValue>>.Add, ICollection<KeyValuePair<TKey, TValue>>.Contains, ICollection<KeyValuePair<TKey, TValue>>.CopyTo, and ICollection<KeyValuePair<TKey, TValue>>.Remove methods of the System.Collections.Generic.ICollection<T> generic interface to manipulate a Dictionary<TKey, TValue> object.

using System;
using System.Collections.Generic;

public class Example
{
    public static void Main()
    {
        // Create a new dictionary of strings, with string keys, and 
        // access it through the generic ICollection interface. The 
        // generic ICollection interface views the dictionary as a 
        // collection of KeyValuePair objects with the same type 
        // arguments as the dictionary. 
        //
        ICollection<KeyValuePair<String, String>> openWith =
            new Dictionary<String, String>();

        // Add some elements to the dictionary. When elements are  
        // added through the ICollection<T> interface, the keys 
        // and values must be wrapped in KeyValuePair objects. 
        //
        openWith.Add(new KeyValuePair<String,String>("txt", "notepad.exe"));
        openWith.Add(new KeyValuePair<String,String>("bmp", "paint.exe"));
        openWith.Add(new KeyValuePair<String,String>("dib", "paint.exe"));
        openWith.Add(new KeyValuePair<String,String>("rtf", "wordpad.exe"));

        Console.WriteLine();
        foreach( KeyValuePair<string, string> element in openWith )
        {
            Console.WriteLine("{0}, {1}", element.Key, element.Value);
        }

        // The Contains method also takes a KeyValuePair object. 
        //
        Console.WriteLine(
            "\nContains(KeyValuePair(\"txt\", \"notepad.exe\")): {0}", 
            openWith.Contains(new KeyValuePair<String,String>("txt", "notepad.exe")));

        // The Remove method takes a KeyValuePair object.) 
        // 
        // Use the Remove method to remove a key/value pair.
        Console.WriteLine("\nRemove(new KeyValuePair(\"dib\", \"paint.exe\"))");
        openWith.Remove(new KeyValuePair<String,String>("dib", "paint.exe"));

        Console.WriteLine();
        foreach( KeyValuePair<string, string> element in openWith )
        {
            Console.WriteLine("{0}, {1}", element.Key, element.Value);
        }

        // Create an array of KeyValuePair objects and copy the  
        // contents of the dictionary to it.  
        // 
        KeyValuePair<string, string>[] copy = 
            new KeyValuePair<string, string>[openWith.Count];
        openWith.CopyTo(copy, 0);

        // List the contents of the array. 
        //
        Console.WriteLine();
        foreach( KeyValuePair<string, string> element in copy )
        {
            Console.WriteLine("{0}, {1}", element.Key, element.Value);
        }
    }
}

/* This code example produces the following output:

txt, notepad.exe
bmp, paint.exe
dib, paint.exe
rtf, wordpad.exe

Contains(KeyValuePair("txt", "notepad.exe")): True

Remove(new KeyValuePair("dib", "paint.exe"))

txt, notepad.exe
bmp, paint.exe
rtf, wordpad.exe

txt, notepad.exe
bmp, paint.exe
rtf, wordpad.exe
 */

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0, 2.0, 1.0

Portable Class Library

Supported in: Portable Class Library

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8
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