C# | Getting the list of keys of a SortedList object

SortedList.GetKeyList Method is used to get the list of keys in a SortedList object.

Syntax:

public virtual System.Collections.IList GetKeyList ();

Return Value: It returns an IList object containing the keys in the SortedList object.

Below programs illustrate the use of above-discussed method:

Example 1:

// C# code for getting the keys
// in a SortedList object
using System;
using System.Collections;

class Geeks {

    // Main Method
    public static void Main(String[] args)
    {

        // Creating a SortedList of integers
        SortedList mylist = new SortedList();

        // Adding elements to SortedList
        mylist.Add("1", "C++");
        mylist.Add("2", "Java");
        mylist.Add("3", "DSA");
        mylist.Add("4", "Python");
        mylist.Add("5", "C#");

        // taking an IList and
        // using GetKeyList method
        IList klist = mylist.GetKeyList();

        // Prints the list of keys
        Console.WriteLine("Key List");

        for (int i = 0; i < mylist.Count; i++)
            Console.WriteLine(klist[i]);
    }
}

Output:

Key List
1
2
3
4
5

Example 2:

// C# code for getting the keys
// in a SortedList object
using System;
using System.Collections;

class Geeks {

    // Main Method
    public static void Main(String[] args)
    {

        // Creating a SortedList of integers
        SortedList mylist = new SortedList();

        // Adding elements to SortedList
        mylist.Add("First", "Ram");
        mylist.Add("Second", "Shyam");
        mylist.Add("Third", "Mohit");
        mylist.Add("Fourth", "Rohit");
        mylist.Add("Fifth", "Manish");

        // taking an IList and
        // using GetKeyList method
        IList klist = mylist.GetKeyList();

        // Prints the list of keys
        Console.WriteLine("Key List");

        // will print the keys in sorted order
        for (int i = 0; i < mylist.Count; i++)
            Console.WriteLine(klist[i]);
    }
}

Output:

Key List
Fifth
First
Fourth
Second
Third

Note:

• The returned IList object is a read-only view of the keys of the SortedList object. Modifications made to the underlying SortedList are immediately reflected in the IList.
• The elements of the returned IList are sorted in the same order as the keys of the SortedList.
• This method is similar to the Keys property but returns an IList object instead of an ICollection object.
• This method is an O(1) operation.

Reference:

• https://docs.microsoft.com/en-us/dotnet/api/system.collections.sortedlist.getkeylist?view=netframework-4.7.2