A RetroSearch Logo

Home - News ( United States | United Kingdom | Italy | Germany ) - Football scores

Search Query:

Showing content from https://www.geeksforgeeks.org/c-sharp/c-sharp-add-key-and-value-into-ordereddictionary-collection/ below:

C# | Add key and value into OrderedDictionary collection

C# | Add key and value into OrderedDictionary collection

Last Updated : 11 Jul, 2025

OrderedDictionary.Add(Object, Object)

method is used to add an entry with the specified key and value into the OrderedDictionary collection with the lowest available index.

Syntax: 
public void Add (object key, object value);
Parameters:
key : The key of the entry to add. value : The value of the entry to add. This value can be null.
Exceptions :

Below given are some examples to understand the implementation in a better way:

Example 1: CSHARP 
// C# code to add key and value
// into OrderedDictionary
using System;
using System.Collections;
using System.Collections.Specialized;

class GFG {

    // Driver method
    public static void Main()
    {

        // Creating a orderedDictionary named myDict
        OrderedDictionary myDict = new OrderedDictionary();

        // Adding key and value in myDict
        myDict.Add("key1", "value1");
        myDict.Add("key2", "value2");
        myDict.Add("key3", "value3");
        myDict.Add("key4", "value4");
        myDict.Add("key5", "value5");

        // Displaying the number of key/value
        // pairs in myDict
        Console.WriteLine(myDict.Count);

        // Displaying the key/value pairs in myDict
        foreach(DictionaryEntry de in myDict)
            Console.WriteLine(de.Key + " --> " + de.Value);
    }
}
Output: 
5
key1 --> value1
key2 --> value2
key3 --> value3
key4 --> value4
key5 --> value5
Example 2: CSHARP 
// C# code to add key and value
// into OrderedDictionary
using System;
using System.Collections;
using System.Collections.Specialized;

class GFG {

    // Driver method
    public static void Main()
    {

        // Creating a orderedDictionary named myDict
        OrderedDictionary myDict = new OrderedDictionary();

        // Adding key and value in myDict
        myDict.Add("key1", "value1");
        myDict.Add("key2", "value2");

        // This should raise "ArgumentException"
        // as an element with the same key already
        // exists in the OrderedDictionary collection.
        myDict.Add("key2", "value3");
        myDict.Add("key4", "value4");
        myDict.Add("key5", "value5");

        // Displaying the number of key/value
        // pairs in myDict
        Console.WriteLine(myDict.Count);

        // Displaying the key/value pairs in myDict
        foreach(DictionaryEntry de in myDict)
            Console.WriteLine(de.Key + " --> " + de.Value);
    }
}
Runtime Error:
Unhandled Exception: System.ArgumentException: Item has already been added. Key in dictionary: 'key2' Key being added: 'key2'
Note:

A key cannot be null, but a value can be.

Reference:

RetroSearch is an open source project built by @garambo | Open a GitHub Issue

Search and Browse the WWW like it's 1997 | Search results from DuckDuckGo

HTML: 3.2 | Encoding: UTF-8 | Version: 0.7.4