I have an API developed in ASP.net Web API 2.0 which inserts records into SharePoint 2013 list.

I am able to assign values to all the fields from the API except for the people picker fields, says

Invalid look-up value.\n\nA look-up field contains invalid data. Please check the value and try again.

My request body is:

{ "siteurl":"http://intranet.sbl.com/GAD/", "listname":"Appointment", "jsonfields":"{\"Title\":\"Test1\",\"Description\":\"Description1\",\"Appointment_x0020_Detail\":\"Description1\",\"Assign_x0020_To\":\"sbl\\\\roman.bajracharya\"}" }

Where "Assign_x0020_To":"sbl\\roman.bajracharya" is the value I am passing for the people picker with title Assign To, and "sbl" is the AD domain and "roman.bajracharya" is the username.

Can anybody help me out on this?

1 Answer 1


To add/update Person or Group field, you need the Id of user. Lets say, user Id in SharePoint site is 11 and the internal name of the field is Assign_x0020_To.

So the request will be like:

var data = {
    Assign_x0020_ToId: 11

If multiple user selection is enabled on Person or group field, you can set it's value like:

Assign_x0020_ToId: { 'results': [11,22] }

Note: You need to add Id with the field's internal name. You can get the internal name of your person or group column by following this article: How to find the Internal name of columns in SharePoint Online?


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