SharePoint 2013 REST - Create list item with user field and lookup field

Question

I'm trying to add an SPListItem to an SPList via REST, but have a problem with User or Group and Lookup (information already on this site).

function adddullitem() {

    var item = {
        "__metadata": { "type": "SP.Data.OfficeReqListItem" },
        "Title": "123",
        "SomeUserorGroupField": "1",
        "SomeLookUpField": "10"
    };
    $.ajax({
        url: "http://SITE/_api/web/lists/getByTitle('LISTNAME')/items",
        type: "POST",
        contentType: "application/json;odata=verbose",
        data: JSON.stringify(item),
        headers: {
            "Accept": "application/json;odata=verbose",
            "X-RequestDigest": $("#__REQUESTDIGEST").val()
        },
        success: function (data) {
            //success(data);
        },
        error: function (data) {
            //failure(data);
        }
    });

}

I'm trying to pass user's ID to User and group field and SPListItem.ID to LookUp field, but it doesn't work.

Answer 1

It depends whether User/Lookup field value is multiple or not, the following formats are used when specifying field value via SharePoint REST:

• Single User/Lookup value format: FieldName: LookupIdVal
• Mutiple User/Lookup value format: FieldName: {"results": [LookupIdVal1,LookupIdVal2] }

How to set multiple lookup/user field value via SharePoint REST API

var listName = 'Tasks';

var itemProperties = {
    '__metadata': { "type": "SP.Data.TasksListItem" },
    "Title": 'New task',
    'AssignedToId': {"results": [12] }  //multi-valued User field value 
};

$.ajax({
    url: _spPageContextInfo.webAbsoluteUrl + "/_api/web/lists/getbytitle('" + listName + "')/items",
    type: "POST",
    contentType: "application/json;odata=verbose",
    data: JSON.stringify(itemProperties),
    headers: {
        "Accept": "application/json;odata=verbose",
        "X-RequestDigest": $("#__REQUESTDIGEST").val()
    },
    success: function (data) {
        console.log(JSON.stringify(data.d));
    },
    error: function (data) {
        console.log(data.responseText);
    }
});

How to set single lookup/user field value via SharePoint REST API

var listName = 'Tasks';

var taskProperties = {
    '__metadata': { "type": "SP.Data.TasksListItem" },
    "Title": 'New task',
    'AssignedToId': 12  //single-valued User field value 
};

$.ajax({
    url: _spPageContextInfo.webAbsoluteUrl + "/_api/web/lists/getbytitle('" + listName + "')/items",
    type: "POST",
    contentType: "application/json;odata=verbose",
    data: JSON.stringify(taskProperties),
    headers: {
        "Accept": "application/json;odata=verbose",
        "X-RequestDigest": $("#__REQUESTDIGEST").val()
    },
    success: function (data) {
        console.log(JSON.stringify(data.d));
    },
    error: function (data) {
        console.log(data.responseText);
    }
});

Answer 2

yes add Id to column names it worked:

Columns :

Course_x0020_Id and Participant

    var courseId = GetQueryStringValues('ID');
    var currentUser  = GetCurrentUser();
    var todaysDate = GetTodaysDate();

    var itemToCreate = {'Category' : 'Register', 'Course_x0020_IdId' : courseId, 'ParticipantId' : currentUser, 'RegistrationDate' : todaysDate};
            var listURL = _spPageContextInfo.webAbsoluteUrl + "/_api/web/lists/getByTitle('listname')/items";
            srvcQuerySPList.createItem(listURL ,itemToCreate)
                .then(
                    function(data){

                        alert("Done");
                    },
                    function(data){
                        alert('Error');
                    }
                );