How to Add Choices to Existing Choice Field Using CSOM in SharePoint 2013 Online

In this blog you will see how to add choices to existing choice field using CSOM in SharePoint 2013 Online.

Code Snippet 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Security;
using System.Text;
using System.Threading.Tasks;
using Microsoft.SharePoint.Client;

namespace CSOMOffice365
{
    class Program
    {
        static void Main(string[] args)
        {

            string userName = "[email protected]";

            Console.WriteLine("Enter your password.");
            SecureString password = GetPassword();

            // ClienContext - Get the context for the SharePoint Online Site
            // SharePoint site URL - https://c986.sharepoint.com

            using (var clientContext = new ClientContext("https://c986.sharepoint.com"))
            {

                // SharePoint Online Credentials
                clientContext.Credentials = new SharePointOnlineCredentials(userName, password);

                // Get the SharePoint web
                Web web = clientContext.Web;

                // Get the list by Title
                List list = web.Lists.GetByTitle("Custom");

                // Get a specific field by Title
                Field field = list.Fields.GetByTitle("Choice");
                FieldChoice fieldChoice = clientContext.CastTo<FieldChoice>(field);
                clientContext.Load(fieldChoice);

                // Execute the query to the server
                clientContext.ExecuteQuery();

                // Add the choice field values
                List<string> options = new List<string>(fieldChoice.Choices);
                options.Add("Option1");
                options.Add("Option2");
                options.Add("Option3");
                fieldChoice.Choices = options.ToArray();

                // Update the choice field
                fieldChoice.Update();

                // Execute the query to the server
                clientContext.ExecuteQuery();

                // Display all the choices
                foreach (string option in fieldChoice.Choices)
                {
                    Console.WriteLine(option);
                }
                Console.ReadLine();
            }

        }

        private static SecureString GetPassword()
        {
            ConsoleKeyInfo info;

            //Get the user's password as a SecureString
            SecureString securePassword = new SecureString();
            do
            {
                info = Console.ReadKey(true);
                if (info.Key != ConsoleKey.Enter)
                {
                    securePassword.AppendChar(info.KeyChar);
                }
            }
            while (info.Key != ConsoleKey.Enter);
            return securePassword;
        }
    }
}

Output