how to update Modified_x0020_By field?

Question

Does anyone have any suggestions on how to go about updating the Modified_x0020_By field? I'm trying everything but it's just not changing. (Before you ask, yes, I do need to update this field.) I can update the Editor no problem but the modified one refuses to update. Unfortunately the web page displays the Editor field, but the CSOM code uses the Modified_x0020_By field.

I've tried changing the readonly on the field but thats not helping me.

Here is my code to first display the values I want, then to try to change two. Yes, you can see my frustration in var name below.

    var url = new Uri("http://sp2013-todd.qalabs.local/ss1/");
    var libraryName = @"Test Doc Sets";
    var folderPath = "/ss1/Test Doc Sets/kellytest3";
    var isFolder = false;

    var ctx = new ClientContext(url);
    var site = ctx.Web;
    var list = site.Lists.GetByTitle(libraryName);

    var query = new CamlQuery();
    query.ViewXml = "<View Scope=\"RecursiveAll\">" +
                    "<Query>" +
                    "<Where>" +
                    "<And>" +
                    "<Contains>" +
                    "<FieldRef Name='FSObjType'/>" +
                    "<Value Type='Integer'>" + (isFolder ? "1" : "0") + "</Value>" +
                    "</Contains>" +
                    "<Eq>" +
                    "<FieldRef Name='FileDirRef'/>" +
                    "<Value Type='Text'>" + folderPath + "</Value>" +
                    "</Eq>" +
                    "</And>" +
                    "</Where>" +
                    "</Query>" +
                    "</View>";

    ListItemCollection collListItem = list.GetItems(query);

    ctx.Load(collListItem, xItems => xItems.Include(
            x => x["Id"],
            x => x["Modified"],
            x => x["Modified_x0020_By"],
            x => x["Editor"],
            x => x.File,
            x => x.File.Author,
            x => x.File.ModifiedBy
        ),
        x => x.ListItemCollectionPosition);

    ctx.ExecuteQuery();

    Console.WriteLine($"There are {collListItem.Count} items to process");

    int firstFile = 0;

    StringBuilder sb = new StringBuilder();
    foreach (var item in collListItem)
    {
        sb.Clear();

        int fileId = item.Id;
        if (firstFile == 0)
            firstFile = fileId;

        sb.Append($"Id = {GetStringValue(fileId)},\t");
        sb.Append($"FileName = '{GetStringValue(item.File.Name)}',\t");
        sb.Append($"File.Author = {item.File.Author.Id}:'${item.File.Author.Email}',\t");
        sb.Append($"File.ModifiedBy = {item.File.ModifiedBy.Id}:'${item.File.ModifiedBy.Email}',");
        sb.Append(Environment.NewLine + "\t");

        foreach (var fv in item.FieldValues)
        {
            if (fv.Value is FieldUserValue)
            {
                var fvUser = ((FieldUserValue)fv.Value);
                sb.Append($"{fv.Key} = {fvUser.LookupId}:'${fvUser.LookupValue}'");
            }
            else
            {
                sb.Append($"{fv.Key} = '{GetStringValue(fv.Value)}',\t");
            }
        }

        Console.WriteLine(sb.ToString() + Environment.NewLine);
    }

    if (firstFile > 0)
    {
        ListItem firstItem = list.GetItemById(firstFile);
        ctx.Load(firstItem);
        ctx.ExecuteQuery();

        User ramDownThroatUser = ctx.Web.EnsureUser(@"i:0#.w|qalabs\administrator");
        ctx.Load(ramDownThroatUser);
        ctx.ExecuteQuery();

        firstItem["Editor"] = "1;#" + ramDownThroatUser;
        firstItem["Modified_x0020_By"] = firstItem["Editor"];
        firstItem.Update();
        ctx.ExecuteQuery();

    }

Answer 1

Here its how you can update the read only fields of SharePoint.

public static void UpdateValue()
    {
        var secureStringPassword = new SecureString();
        "*******".ToList().ForEach(c => secureStringPassword.AppendChar(c));
        using (ClientContext cc=new ClientContext(siteUrl))
        {
            cc.Credentials = new SharePointOnlineCredentials("[email protected]", secureStringPassword);

            var web = cc.Web;
            var site = cc.Site;

            cc.Load(web);
            cc.Load(site);
            cc.ExecuteQuery();

            List oList = cc.Web.Lists.GetByTitle("test");


            ListItemCollection collListItem = oList.GetItems(CamlQuery.CreateAllItemsQuery());

            cc.Load(collListItem);

            cc.ExecuteQuery();
            oList.Fields.GetByInternalNameOrTitle("Author").ReadOnlyField = false;
            oList.Fields.GetByInternalNameOrTitle("Editor").ReadOnlyField = false;
            oList.Fields.GetByInternalNameOrTitle("Modified").ReadOnlyField = false;
            oList.Fields.GetByInternalNameOrTitle("Created").ReadOnlyField = false;
            oList.Update();
            cc.ExecuteQuery();
            foreach (ListItem oListItem in collListItem)
            {
                oListItem["Author"] = CreatedByValue;
                oListItem["Editor"] = ModifiedByValue;
                oListItem["Modified"] = ModifiedDate;
                oListItem["Created"] = CreatedDate;
                oListItem.Update();
                cc.ExecuteQuery();

            }
            oList.Fields.GetByInternalNameOrTitle("Author").ReadOnlyField = true;
            oList.Fields.GetByInternalNameOrTitle("Editor").ReadOnlyField = true;
            oList.Fields.GetByInternalNameOrTitle("Modified").ReadOnlyField = true;
            oList.Fields.GetByInternalNameOrTitle("Created").ReadOnlyField = true;
            oList.Update();
            cc.ExecuteQuery();
        }
    }