this is my controller action method-------
    public HttpResponseMessage PostPost(Post post)
    { 
     // previosly i was using simple membership to get id of logged in user
       // post.PostedBy = WebSecurity.CurrentUserId;
          post.PostedBy = User.Identity.GetUserId<int>();
           post.PostedDate = DateTime.UtcNow;
        ModelState.Remove("post.PostedBy");
        ModelState.Remove("post.PostedDate");
        if (ModelState.IsValid)
        {
            db.Posts.Add(post);
            db.SaveChanges();
   // now i am facing problem at this line. it is saying that
  //Operator '=='   cannot be applied to operands of type 'int' and 'string'  
            var usr = db.Users.FirstOrDefault(x => x.Id == post.PostedBy);
my code was working fine when i was using simple membership.what should i try to make it working. here, post is a class with property PostedBy as int and i want to assign current loggedIn userId value to this property.
 
     
    