MVC 3 application run successfully in vs2012 but can't insert new record

[denmarkstan]

I am new to vs2012.I am trying to run MVC3 tutorial to experience the working of vs2012. I have ran thesame tutorial on vs2010 successfully and inserted new record. Now I want to run thesame tutorial on vs2012. On both cases, i am using sqlserver management studio and entity framework(dotnet 4.0).I used SSMS2008 for VS2010 and SSMS2012 for VS2012. Program ran successfully on vs2012 but was unable to insert new record to database.Note i have googled this and tried
many suggestions all to no avail.. Here is the code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using LatestBlog.Models;
using System.Data.EntityModel;
using System.Text;

namespace LatestBlog.Controllers
{
    public class PostsController : Controller
    {
        private BlogEntities model = new BlogEntities();

        public ActionResult Index()
        {
            return View();
        }
        [ValidateInput(false)]
        public ActionResult Update(int? id, string title, string body, DateTime datetime, string tags)
        {
            if (!IsAdmin)
            {
                return RedirectToAction("Index");
            }
            Post post = GetPost(id);
            post.Title = title;
            post.Body = body;
            post.DateTime = datetime;
            post.Tags.Clear();
            tags = tags ?? string.Empty;
            string[] tagNames = tags.Split(new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
            foreach (string tagname in tagNames)
            {
                post.Tags.Add(GetTag(tagname));
            }
            if (!id.HasValue)
            {
                try
                {
                    //model.AddToPost(post);
                    model.Posts.Add(post);
                }
                catch (Exception exp)
                {
                    throw new Exception("ERROR: Unable to Add post to database - " + exp.Message.ToString(), exp);
                }                 

            }
            model.SaveChanges();
            return RedirectToAction("Details", new { id = post.ID });
        }
        public ActionResult Edit(int? id)
        {
            Post post = GetPost(id);
            StringBuilder tagList = new StringBuilder();//...........................
            foreach (Tag tag in post.Tags)
            {
                tagList.AppendFormat("{0}", tag.Name);
            }
            ViewBag.Tags = tagList.ToString();
            return View(post);
        }
        private Tag GetTag(string tagName)
        {
            return model.Tags.Where(x => x.Name == tagName).FirstOrDefault() ?? new Tag() { Name = tagName };
        }

        private Post GetPost(int? id)
        {
            return id.HasValue ? model.Posts.Where(x => x.ID == id).First() : new Post() { ID = -1 };
        }
        public bool IsAdmin
        {
            get
            {
                // To do, don't just return true
                return true; //Session["IsAdmin"] != null && (bool)Session["IsAdmin"]; 
            }
        }
    }
}



Connection Strings (I have tried):
 <add name="BlogEntities" connectionString="metadata=res://*/Models.Blog.csdl|res://*/Models.Blog.ssdl|res://*/Models.Blog.msl;provider=System.Data.SqlClient;provider connection string=&quot;data source=.;initial catalog=Blog;integrated security=True;MultipleActiveResultSets=True; " providerName="System.Data.EntityClient" />

    <add name="DefaultConnection" providerName="System.Data.SqlClient" connectionString="Data Source=(LocalDb)\v11.0;Initial Catalog=aspnet-LatestBlog-20150104203236;Integrated Security=SSPI;AttachDBFilename=|DataDirectory|\aspnet-LatestBlog-20150104203236.mdf" />