StringDictionary.Add Method

Adds an entry with the specified key and value into the StringDictionary.

Namespace: System.Collections.Specialized
Assembly: System (in system.dll)

public virtual void Add (
	string key,
	string value
)
public void Add (
	String key, 
	String value
)
public function Add (
	key : String, 
	value : String
)
Not applicable.

Parameters

key

The key of the entry to add.

value

The value of the entry to add. The value can be a null reference (Nothing in Visual Basic).

Exception typeCondition

ArgumentNullException

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

ArgumentException

An entry with the same key already exists in the StringDictionary.

NotSupportedException

The StringDictionary is read-only.

The key is handled in a case-insensitive manner; it is translated to lowercase before it is added to the string dictionary.

This method is an O(1) operation.

The following code example demonstrates how to add and remove elements from a StringDictionary.

using System;
using System.Collections;
using System.Collections.Specialized;

public class SamplesStringDictionary  {

   public static void Main()  {

      // Creates and initializes a new StringDictionary.
      StringDictionary myCol = new StringDictionary();
      myCol.Add( "red", "rojo" );
      myCol.Add( "green", "verde" );
      myCol.Add( "blue", "azul" );

      // Displays the values in the StringDictionary.
      Console.WriteLine( "Initial contents of the StringDictionary:" );
      PrintKeysAndValues( myCol );

      // Deletes an element.
      myCol.Remove( "green" );
      Console.WriteLine( "The collection contains the following elements after removing \"green\":" );
      PrintKeysAndValues( myCol );

      // Clears the entire collection.
      myCol.Clear();
      Console.WriteLine( "The collection contains the following elements after it is cleared:" );
      PrintKeysAndValues( myCol );

   }

   public static void PrintKeysAndValues( StringDictionary myCol )  {
      Console.WriteLine( "   KEY        VALUE" );
      foreach ( DictionaryEntry de in myCol )
         Console.WriteLine( "   {0,-10} {1}", de.Key, de.Value );
      Console.WriteLine();
   }

}

/*
This code produces the following output.

Initial contents of the StringDictionary:
   KEY        VALUE
   green      verde
   red        rojo
   blue       azul

The collection contains the following elements after removing "green":
   KEY        VALUE
   red        rojo
   blue       azul

The collection contains the following elements after it is cleared:
   KEY        VALUE

*/

import System.*;
import System.Collections.*;
import System.Collections.Specialized.*;

public class SamplesStringDictionary
{
    public static void main(String[] args)
    {
        // Creates and initializes a new StringDictionary.
        StringDictionary myCol = new StringDictionary();

        myCol.Add("red", "rojo");
        myCol.Add("green", "verde");
        myCol.Add("blue", "azul");

        // Displays the values in the StringDictionary.
        Console.WriteLine("Initial contents of the StringDictionary:");
        PrintKeysAndValues(myCol);

        // Deletes an element.
        myCol.Remove("green");
        Console.WriteLine("The collection contains the following elements" 
            + " after removing \"green\":");
        PrintKeysAndValues(myCol);

        // Clears the entire collection.
        myCol.Clear();
        Console.WriteLine("The collection contains the following elements" 
            + " after it is cleared:");
        PrintKeysAndValues(myCol);
    }//main

    public static void PrintKeysAndValues(StringDictionary myCol)
    {
        Console.WriteLine("   KEY        VALUE");
        IEnumerator objEnum = myCol.GetEnumerator();
        while (objEnum.MoveNext()) {
            DictionaryEntry de = (DictionaryEntry)objEnum.get_Current();
            Console.WriteLine("   {0,-10} {1}", de.get_Key(), de.get_Value());
        }
        Console.WriteLine();
    } //PrintKeysAndValues
} //SamplesStringDictionary

/*
This code produces the following output.

Initial contents of the StringDictionary:
   KEY        VALUE
   red        rojo
   blue       azul
   green      verde

The collection contains the following elements after removing "green":
   KEY        VALUE
   red        rojo
   blue       azul

The collection contains the following elements after it is cleared:
   KEY        VALUE

*/

Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0

XNA Framework

Supported in: 1.0

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