Get or set the value associated with specified key in SortedList in C#

In C#, the SortedList collection allows you to get or set values using the indexer syntax with square brackets. The indexer property list[key] provides both read and write access to values associated with specific keys in the sorted list.

Syntax

Following is the syntax for getting a value from SortedList −

object value = sortedList[key];

Following is the syntax for setting a value in SortedList −

sortedList[key] = value;

If the key exists, it updates the value. If the key doesn't exist, it adds a new key-value pair.

Getting Values from SortedList

You can retrieve values from a SortedList using the key as an index −

using System;
using System.Collections;

public class Demo {
   public static void Main() {
      SortedList list = new SortedList();
      list.Add("A", "Books");
      list.Add("B", "Electronics");
      list.Add("C", "Appliances");
      list.Add("D", "Pet Supplies");
      list.Add("E", "Clothing");
      list.Add("F", "Footwear");
      
      Console.WriteLine("Value associated with key D = " + list["D"]);
      Console.WriteLine("Value associated with key B = " + list["B"]);
      Console.WriteLine("Value associated with key F = " + list["F"]);
   }
}

The output of the above code is −

Value associated with key D = Pet Supplies
Value associated with key B = Electronics
Value associated with key F = Footwear

Setting Values in SortedList

You can update existing values or add new key-value pairs using the indexer −

using System;
using System.Collections;

public class Demo {
   public static void Main() {
      SortedList list = new SortedList();
      list.Add("A", "Books");
      list.Add("B", "Electronics");
      list.Add("C", "Appliances");
      list.Add("D", "Pet Supplies");
      list.Add("E", "Clothing");
      list.Add("F", "Footwear");
      
      Console.WriteLine("Value associated with key E = " + list["E"]);
      list["E"] = "HDD";
      Console.WriteLine("Value associated with key E [Updated] = " + list["E"]);
      
      // Adding a new key-value pair
      list["G"] = "Sports";
      Console.WriteLine("Value associated with key G [New] = " + list["G"]);
      Console.WriteLine("Total items: " + list.Count);
   }
}

The output of the above code is −

Value associated with key E = Clothing
Value associated with key E [Updated] = HDD
Value associated with key G [New] = Sports
Total items: 7

Key Features

• The indexer allows both getting and setting values by key.

• If you try to get a value with a non-existent key, it throws a KeyNotFoundException.

• If you set a value with a new key, it automatically adds the key-value pair to the collection.

• Keys are maintained in sorted order automatically.

Conclusion

The SortedList indexer property provides a convenient way to access and modify values by key. Use list[key] to get values and list[key] = value to set or update values, with automatic sorting maintained throughout operations.