Implementation:

  • Declare the public variables.
  • Get Host Web URL and App web URL in Document Ready.
  • Then call MakeMultiSelectionToUserField method.
  • Get app context site from AddEnterpriseColumnToList method.
  • Get web and Task list.
  • Get assigned to filed by Internal name.
  • Then case to the assigned to field to user field.
  • Set Allow multiple values to True.
  • Load the user Field.
  • Execute the request.
  • Show result in success method.
  • Failure method are used to catch the errors.

  1. //Varibles Declaration
  2. var appWebURL, hostWebURL, appCtxSite, context;
  4. // This code runs when the DOM is ready and creates a context object which is needed to use the SharePoint object model
  5. $(document).ready(function () {
  6. hostWebURL = decodeURIComponent(manageQueryStringParameter('SPHostUrl'));
  7. appWebURL = decodeURIComponent(manageQueryStringParameter('SPAppWebUrl'));
  8. MakeMultiSelectionToUserField();
  9. });
  10. //Make assigned to field accept multivalues
  11. function MakeMultiSelectionToUserField() {
  12. hostWebURL = decodeURIComponent(manageQueryStringParameter('SPHostUrl'));
  13. appWebURL = decodeURIComponent(manageQueryStringParameter('SPAppWebUrl'))
  14. var context = new SP.ClientContext(appWebURL);
  15. var appCtxSite = new SP.AppContextSite(context, hostWebURL);
  16. //get Web
  17. var web = appCtxSite.get_web();
  18. //Get list by title
  19. var list = web.get_lists().getByTitle('Tasks');
  20. //Get assigned to by internal name
  21. var field = list.get_fields().getByInternalNameOrTitle("AssignedTo");
  22. var userField = context.castTo(field, SP.FieldUser);
  23. //Manage allow multiple values for assigned to column
  24. userField.set_allowMultipleValues(true);
  25. userField.update();
  26. context.load(userField);
  27. context.executeQueryAsync(function () {
  28. //Success Method
  29. alert(userField.get_allowMultipleValues());
  30. console.log("Field added successfully!!" + field);
  31. }
  32. , function (sender, args) {
  33. //Failure method Method
  34. console.log("Request failed" + args.get_message());
  35. });
  37. }
  39. //Getting host web url and app web url from query string using this method
  40. function manageQueryStringParameter(paramToRetrieve) {
  41. var params = document.URL.split("?")[1].split("&");
  42. var strParams = "";
  43. for (var i = 0; i < params.length; i = i + 1) {
  44. var singleParam = params[i].split("=");
  45. if (singleParam[0] == paramToRetrieve) {
  46. return singleParam[1];
  47. }
  48. }
  49. }
Summary

In this blog, we have explored how to allow multiple selection users in SharePoint task list assigned to field using JavaScript Object model. I hope above explained solution is very useful to you. Happy Coding!