Updating read only fields using client side object model in SharePoint 2013

Question

I am using managed client object model for creating list item, I want to update the Author, Created and Editor fields from code. I have tried lot of things like:

var listItem = list.AddItem(listItemCreationInformation); 
listItem["Title"] = "Migrated Date"; 
listItem["Modified"] = DateTime.Now.AddDays(-10); 

//Date Value listItem["Created"] = DateTime.Now.AddDays(-10); 
listItem["Author"] = GetUser(clientContext, "Domain\\userId"); 
listItem["Editor"] = GetUser(clientContext, "Domain\\userId"); 
listItem["CORID"] = folderPath; 
listItem.Update(); 

clientContext.ExecuteQuery();

Answer 1

I'm 99% sure that you need to retrieve the item back and then update those fields. try this:

var newListItem = list.AddItem(listItemCreationInformation); 
var listItem = list.getItemById(newListItem.Id);

listItem["Title"] = "Migrated Date"; 
listItem["Modified"] = DateTime.Now.AddDays(-10); 

//Date Value listItem["Created"] = DateTime.Now.AddDays(-10); 
listItem["Author"] = GetUser(clientContext, "Domain\\userId"); 
listItem["Editor"] = GetUser(clientContext, "Domain\\userId"); 
listItem["CORID"] = folderPath; 
listItem.Update(); 

clientContext.ExecuteQuery();

Note the 2nd line that fetches the newly created item.

Answer 2

As these are read only fields, you might not be able to update it as per my understanding.

However you can try following code whether it works or not as its trying to change the readonly property of the list:

FieldUserValue fldUser = new FieldUserValue();
fldUser.LookupId = oUser.Id;
clientContext.Load(fldUser);
clientContext.ExecuteQuery();
oListItem["Author"] = fldUser;
oListItem["Editor"] = fldUser;

If the above code doesn't work means, the Author and Editor field maybe a ReadOnly Field, So we have to remove the readOnly mode from that field.

list.Fields.GetByInternalNameOrTitle("Author").ReadOnlyField = false;