C# SortedDictionary.Add() Method

The SortedDictionary.Add() method in C# is used to add an element with the specified key and value into the SortedDictionary<TKey, TValue>. Unlike regular dictionaries, SortedDictionary maintains elements in sorted order based on the keys.

Syntax

Following is the syntax for the Add() method −

public void Add(TKey key, TValue value);

Parameters

• key − The key of the element to add. Cannot be null.

• value − The value of the element to add. Can be null if TValue is a reference type.

Return Value

This method does not return a value. It has a void return type.

Using Add() with Integer Keys

Example

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

public class Demo {
   public static void Main() {
      SortedDictionary<int, string> sortedDict = new SortedDictionary<int, string>();
      sortedDict.Add(100, "Mobile");
      sortedDict.Add(200, "Laptop");
      sortedDict.Add(300, "Desktop");
      sortedDict.Add(400, "Speakers");
      sortedDict.Add(500, "Headphone");
      sortedDict.Add(600, "Earphone");
      
      Console.WriteLine("SortedDictionary key-value pairs...");
      IDictionaryEnumerator demoEnum = sortedDict.GetEnumerator();
      while (demoEnum.MoveNext())
         Console.WriteLine("Key = " + demoEnum.Key + ", Value = " + demoEnum.Value);
   }
}

The output of the above code is −

SortedDictionary key-value pairs...
Key = 100, Value = Mobile
Key = 200, Value = Laptop
Key = 300, Value = Desktop
Key = 400, Value = Speakers
Key = 500, Value = Headphone
Key = 600, Value = Earphone

Using Add() with String Keys

Example

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

public class Demo {
   public static void Main() {
      SortedDictionary<string, string> sortedDict = new SortedDictionary<string, string>();
      sortedDict.Add("A", "John");
      sortedDict.Add("B", "Andy");
      sortedDict.Add("C", "Tim");
      sortedDict.Add("D", "Ryan");
      sortedDict.Add("E", "Kevin");
      sortedDict.Add("F", "Katie");
      sortedDict.Add("G", "Brad");
      
      Console.WriteLine("SortedDictionary key-value pairs...");
      IDictionaryEnumerator demoEnum = sortedDict.GetEnumerator();
      while (demoEnum.MoveNext())
         Console.WriteLine("Key = " + demoEnum.Key + ", Value = " + demoEnum.Value);
      Console.WriteLine("\nThe SortedDictionary has the key F? = " + sortedDict.ContainsKey("F"));
   }
}

The output of the above code is −

SortedDictionary key-value pairs...
Key = A, Value = John
Key = B, Value = Andy
Key = C, Value = Tim
Key = D, Value = Ryan
Key = E, Value = Kevin
Key = F, Value = Katie
Key = G, Value = Brad

The SortedDictionary has the key F? = True

Exception Handling

Example

using System;
using System.Collections.Generic;

public class Demo {
   public static void Main() {
      SortedDictionary<string, int> sortedDict = new SortedDictionary<string, int>();
      
      try {
         sortedDict.Add("First", 10);
         sortedDict.Add("Second", 20);
         Console.WriteLine("Elements added successfully");
         
         // This will throw ArgumentException
         sortedDict.Add("First", 30);
      }
      catch (ArgumentException ex) {
         Console.WriteLine("Error: " + ex.Message);
      }
   }
}

The output of the above code is −

Elements added successfully
Error: An item with the same key has already been added.

Conclusion

The SortedDictionary.Add() method adds key-value pairs while maintaining sorted order based on keys. It throws an ArgumentException if you try to add a duplicate key, making it essential to check for key existence before adding elements.