Code Snippet
  1. using System;
  2. using System.Collections.Generic;
  3. using System.Linq;
  4. using System.Net;
  5. using System.Security;
  6. using System.Text;
  7. using System.Threading.Tasks;
  8. using Microsoft.SharePoint.Client;
  10. namespace CSOMOffice365
  11. {
  12. class Program
  13. {
  14. static void Main(string[] args)
  15. {
  17. string userName = "[email protected]";
  19. Console.WriteLine("Enter your password.");
  20. SecureString password = GetPassword();
  22. // ClienContext - Get the context for the SharePoint Online Site
  23. // SharePoint site URL - https://c986.sharepoint.com
  25. using (var clientContext = new ClientContext("https://c986.sharepoint.com"))
  26. {
  28. // SharePoint Online Credentials
  29. clientContext.Credentials = new SharePointOnlineCredentials(userName, password);
  31. // Get the SharePoint web
  32. Web web = clientContext.Web;
  34. // Get the list by Title
  35. List list = web.Lists.GetByTitle("Custom");
  37. // Get a specific field by Title
  38. Field field = list.Fields.GetByTitle("Choice");
  39. FieldChoice fieldChoice = clientContext.CastTo<FieldChoice>(field);
  40. clientContext.Load(fieldChoice);
  42. // Execute the query to the server
  43. clientContext.ExecuteQuery();
  45. // Add the choice field values
  46. List<string> options = new List<string>(fieldChoice.Choices);
  47. options.Add("Option1");
  48. options.Add("Option2");
  49. options.Add("Option3");
  50. fieldChoice.Choices = options.ToArray();
  52. // Update the choice field
  53. fieldChoice.Update();
  55. // Execute the query to the server
  56. clientContext.ExecuteQuery();
  58. // Display all the choices
  59. foreach (string option in fieldChoice.Choices)
  60. {
  61. Console.WriteLine(option);
  62. }
  63. Console.ReadLine();
  64. }
  66. }
  68. private static SecureString GetPassword()
  69. {
  70. ConsoleKeyInfo info;
  72. //Get the user's password as a SecureString
  73. SecureString securePassword = new SecureString();
  74. do
  75. {
  76. info = Console.ReadKey(true);
  77. if (info.Key != ConsoleKey.Enter)
  78. {
  79. securePassword.AppendChar(info.KeyChar);
  80. }
  81. }
  82. while (info.Key != ConsoleKey.Enter);
  83. return securePassword;
  84. }
  85. }
  86. }
Output