Assign Managed Metadata column values from source page to another publishing page using CSOM

Question

I am writing a CSOM to get the values of a managed metadata column (sourceWikiPage) and assign it to another page (newpage), here is my code:-

File sourceWikiPage = context.Site.RootWeb.GetFileByServerRelativeUrl("source.aspx");
context.Load(sourceWikiPage, items => items.ListItemAllFields);
context.ExecuteQuery();
PublishingPageInformation publishingPageInfo = new PublishingPageInformation();
publishingPageInfo.Name = newPageName+".aspx";
publishingPageInfo.PageLayoutListItem = layout;
PublishingPage pPage = pWeb.AddPublishingPage(publishingPageInfo);
ListItem newpage = pPage.ListItem;
newpage["Subjects"] = sourceWikiPage.ListItemAllFields["Subjects"] as TaxonomyFieldValue;//this does not have any effect!!
newpage.Update();
context.Load(newpage);
context.ExecuteQuery();

Now the page will be created, but the Subject managed metadata site column (which allow multiple values) will not have any values..

So can anyone advice?

Answer 1

Please refer the following code snippet to create publishing page and set multi-value managed metadata based on another item:

 using System;
 using System.Collections.Generic;
 using System.Linq;   
 using Microsoft.SharePoint.Client;
 using Microsoft.SharePoint.Client.Publishing;
 using Microsoft.SharePoint.Client.Taxonomy;

 public static string CreatePublishingPage(ClientContext context)
    {
        string pageLibrary = "Pages";
        string pageLayout = "EnterpriseWiki";
        string pageName = "MyNewPublishingPage.aspx";
        string pageDisplayName = pageName.Split('.')[0];
        string pageURL = string.Empty;

        try
        {

            Web webSite = context.Web;
            context.Load(webSite);
            PublishingWeb web = PublishingWeb.GetPublishingWeb(context, webSite);
            context.Load(web);

            if (web != null)
            {
                // Get Pages Library
                List pages = context.Site.RootWeb.Lists.GetByTitle(pageLibrary);
                ListItemCollection existingPages = pages.GetItems(CamlQuery.CreateAllItemsQuery());
                context.Load(existingPages, items => items.Include(item => item.DisplayName).Where(obj => obj.DisplayName == pageDisplayName));
                context.ExecuteQuery();

                // Check if page already exists
                if (existingPages != null && existingPages.Count > 0)
                {
                    // Page already exists
                    Console.WriteLine("Page already exists.\n");
                    pageURL = context.Web.ServerRelativeUrl + "/" + pageLibrary + "/" + pageName;
                }
                else
                {
                    // Get Publishing Page Layouts
                    Console.WriteLine("Creating Page...\n");
                    List publishingLayouts = context.Site.RootWeb.Lists.GetByTitle("Master Page Gallery");
                    ListItemCollection allItems = publishingLayouts.GetItems(CamlQuery.CreateAllItemsQuery());

                    context.Load(allItems, items => items.Include(item => item.DisplayName).Where(obj => obj.DisplayName == pageLayout));
                    context.ExecuteQuery();

                    ListItem layout = allItems.Where(x => x.DisplayName == pageLayout).FirstOrDefault();
                    context.Load(layout);
                    File tempWikiPage = context.Site.RootWeb.GetFileByServerRelativeUrl("/sites/dev/Pages/Temp.aspx");
                    context.Load(tempWikiPage,items => items.ListItemAllFields);
                    context.ExecuteQuery();
                    // Create a publishing page
                    PublishingPageInformation publishingPageInfo = new PublishingPageInformation();
                    publishingPageInfo.Name = pageName;
                    publishingPageInfo.PageLayoutListItem = layout;

                    PublishingPage publishingPage = web.AddPublishingPage(publishingPageInfo);

                    TaxonomyFieldValueCollection sourceValue = tempWikiPage.ListItemAllFields["Subjects"] as TaxonomyFieldValueCollection;
                    string[] termValuesarrary;
                    List<string> termValues = new List<string>();
                    foreach (TaxonomyFieldValue taxProductFieldValue in sourceValue)
                    {
                        termValues.Add("-1;#" + taxProductFieldValue.Label + "|" + taxProductFieldValue.TermGuid);
                    }
                    termValuesarrary = termValues.ToArray();
                    string termValuesstring = string.Join(";#", termValuesarrary);
                    FieldCollection fields = context.Site.RootWeb.Lists.GetByTitle("Pages").Fields;
                    context.Load(fields);
                    context.ExecuteQuery();
                    Field SubjectField = fields.GetByTitle("Subjects");
                    context.Load(SubjectField);
                    context.ExecuteQuery();
                    TaxonomyField txField = context.CastTo<TaxonomyField>(SubjectField);
                    var newtermValues = new TaxonomyFieldValueCollection(context, termValuesstring, txField);
                    txField.SetFieldValueByValueCollection(publishingPage.ListItem, newtermValues);
                    publishingPage.ListItem["Title"] = pageDisplayName;
                    publishingPage.ListItem["Standard"] = tempWikiPage.ListItemAllFields["Standard"];
                    publishingPage.ListItem.Update();
                    publishingPage.ListItem.File.CheckIn(string.Empty, CheckinType.MajorCheckIn);
                    publishingPage.ListItem.File.Publish(string.Empty);
                    context.Load(publishingPage);
                    context.Load(publishingPage.ListItem.File, obj => obj.ServerRelativeUrl);
                    context.ExecuteQuery();

                    pageURL = context.Web.ServerRelativeUrl + "/" + pageLibrary + "/" + pageName;
                    Console.WriteLine("Page Created.\n");
                }
            }
        }
        catch (Exception e)
        {
            Console.WriteLine("Failed. Error: " + e);
        }
        return pageURL;
    }