Post postUpdate = postsListReq.Execute().Items[0];

postUpdate.Title = "Title Changed";

PostsResource.UpdateRequest blogUpdate = postRes.Update(postUpdate, blog.Id, postUpdate.Id);
blogUpdate.Execute();

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

using Google.Apis.Blogger.v3;
using Google.Apis.Blogger.v3.Data;
using Google.Apis.Services;
using System.Diagnostics;
using Google.Apis.Authentication.OAuth2;
using Google.Apis.Authentication.OAuth2.DotNetOpenAuth;
using DotNetOpenAuth.OAuth2;
using Google.Apis.Util;


namespace BloggerTest
{
    class Program
    {
        static void Main(string[] args)
        {
            string apiKey= "{API-KEY}";
            string blogUrl= "{BLOG-URL}";

            string clientID = "{CLIENT_ID}";
            string clientSec = "{CLIENT_SECRET}";

            NativeApplicationClient provider = new NativeApplicationClient(GoogleAuthenticationServer.Description)
            {
                ClientIdentifier = clientID,
                ClientSecret = clientSec
            };

            OAuth2Authenticator<NativeApplicationClient> auth = new OAuth2Authenticator<NativeApplicationClient>(provider, getAuth);

            BloggerService blogService = new BloggerService(new BaseClientService.Initializer()
            {
                Authenticator = auth,
                ApplicationName = "BloggerTest"
            });


            BlogsResource.GetByUrlRequest getReq = blogService.Blogs.GetByUrl(blogUrl);
            getReq.Key = apiKey;
            Blog blog = getReq.Execute();

            Console.WriteLine("Blog ID: " + blog.Id);
            Console.WriteLine();

            PostsResource postRes = new PostsResource(blogService);
            PostsResource.ListRequest postsListReq = postRes.List(blog.Id);

            string firstToken = "";

            while (true)
            {
                PostList posts = postsListReq.Execute();
                postsListReq.PageToken = posts.NextPageToken;

                if (firstToken == "")
                {
                    firstToken = posts.NextPageToken;
                }
                else if (firstToken != "" && posts.NextPageToken == firstToken)
                {
                    // repeated

                    break;
                }

                for (int i = 0; i < posts.Items.Count; i++)
                {
                    Console.WriteLine("Title: " + posts.Items[i].Title);
                    Console.WriteLine("URL: " + posts.Items[i].Url);
                }

            }

            Post postUpdate = postsListReq.Execute().Items[0];
            postUpdate.Title = "Title Changed";

            PostsResource.UpdateRequest blogUpdate = postRes.Update(postUpdate, blog.Id, postUpdate.Id);
            blogUpdate.Execute();

            Console.WriteLine();
            Console.WriteLine("Done...");

            Console.ReadKey();



        }

        private static IAuthorizationState getAuth(NativeApplicationClient arg)
        {
            IAuthorizationState state = new AuthorizationState(new[] { BloggerService.Scopes.Blogger.GetStringValue() })
                {
                    Callback = new Uri(NativeApplicationClient.OutOfBandCallbackUrl)
                };
            Uri authUri = arg.RequestUserAuthorization(state);
            Process.Start(authUri.ToString());
            Console.WriteLine("Please enter auth code:");
            string authCode = Console.ReadLine();
            return arg.ProcessUserAuthorization(authCode, state);
        }


    }
}