Change all webpart titles in a specific SP2010 pages library by CSOM.

UpdateWebPartTitles.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Text;
using Microsoft.SharePoint.Client;
using Microsoft.SharePoint.Client.WebParts;

namespace UpdateWebPartTitles
{
    class Program
    {
        static void Main(string[] args)
        {
            ChangeWebPartTitle source = new ChangeWebPartTitle();
            source.Login(args[0], args[1], args[2], args[3]);
            source.ChangeWebPartTitles(args[4], args[5], args[6]);
        }
    }

    class ChangeWebPartTitle
    {
        private ClientContext clientContext { get; set; }

        private string OldTitle { get; set; }

        private string NewTitle { get; set; }

        internal void Login(string webUrl, string username, string domain, string password)
        {
            clientContext = new ClientContext(webUrl);
            ICredentials creds = new NetworkCredential(username, password, domain);
            clientContext.Credentials = creds;
        }

        internal void ChangeWebPartTitles(string oldValue, string newValue, string pagesListTitle)
        {
            OldTitle = oldValue;
            NewTitle = newValue;

            Web web = clientContext.Web;
            clientContext.Load(web, w => w.Webs, w => w.Title, w => w.Lists);
            clientContext.ExecuteQuery();

            var pagesList = web.Lists.GetByTitle(pagesListTitle);
            clientContext.Load(pagesList, p=> p.Title);
            clientContext.ExecuteQuery();
            ProcessList(web, pagesList);

        }

        private void ProcessList(Web web, List list)
        {
            ListItemCollectionPosition itemPosition = null;
            while (true)
            {
                CamlQuery camlQuery = CamlQuery.CreateAllItemsQuery();
                ListItemCollection listItems = list.GetItems(camlQuery);
                clientContext.Load(listItems);
                clientContext.ExecuteQuery();
                itemPosition = listItems.ListItemCollectionPosition;
                foreach (ListItem listItem in listItems)
                {
                    File file = listItem.File;
                    clientContext.Load(file, f => f.CheckOutType, f => f.Title);
                    UpdateWebPartTitles(listItem.File);

                    Approve(listItem);

                }
                if (itemPosition == null)
                    break;
            }
        }

        private void Approve(ListItem listItem)
        {
            int status = Convert.ToInt32(listItem["_ModerationStatus"]);
            if (status != 0)
            {
                listItem["_ModerationStatus"] = 0;
                listItem.Update();
                clientContext.ExecuteQuery();
            }
        }

        private void UpdateWebPartTitles(File file)
        {
            LimitedWebPartManager limitedWebPartManager = file.GetLimitedWebPartManager(PersonalizationScope.Shared);

            clientContext.Load(limitedWebPartManager.WebParts,
                wps => wps.Include(
                wp => wp.WebPart.Title));

            clientContext.ExecuteQuery();

            if (limitedWebPartManager.WebParts.Count == 0)
            {
                return;
            }
            bool pageChanged = false;
            foreach (var wpd in limitedWebPartManager.WebParts)
            {
                bool webpartChanged = ChangeWebPartTitle(file, wpd);
                pageChanged = pageChanged || webpartChanged;
            }
            if (pageChanged)
            {
                file.CheckIn("Changed WPTitle", CheckinType.MajorCheckIn);
                file.Publish("Changed WPTitle");
                clientContext.ExecuteQuery();
            }
        }

        /// <summary>
        /// Changes the web part title.
        /// </summary>
        /// <param name="webpartPage">The WebPart Page.</param>
        /// <param name="wpd">The WebPartDefinition.</param>
        /// <returns><c>true</c> when the webpart has changed, <c>false</c> otherwise.</returns>
        private bool ChangeWebPartTitle(File webpartPage, WebPartDefinition wpd)
        {
            WebPart webpart = wpd.WebPart;
            if (webpart.Title.ToLowerInvariant() == OldTitle.ToLowerInvariant())
            {
                if (webpartPage.CheckOutType == CheckOutType.None)
                {
                    webpartPage.CheckOut();
                    clientContext.ExecuteQuery();
                }
                webpart.Title = NewTitle;
                wpd.SaveWebPartChanges();
                return true;
            }
            return false;
        }

        
    }
}