title: Can't add more then one user to the table. Identity Insert is set to off
body: <p>Here is the error i get when i click on submit on my form to add a new user. I tried to set IDENTITY to ON trough query on User Table and it didn't help. I don't know how can i set it on and off when i'm not inserting data myself. Any suggestions? </p>
  
  <p><img src="https://i.stack.imgur.com/YpNCh.png" alt="">
  Here is my controller: </p>
  
  <pre><code>    [HttpPost]
      [ValidateAntiForgeryToken]
      public ActionResult Register(User U)
      {
          if (ModelState.IsValid)
          {
              using (SomeEntities dc = new SomeEntities ())
              {
                  //you should check duplicate registration here 
                  dc.Users.Add(U);
                  dc.SaveChanges();
                  ModelState.Clear();
                  U = null;
                  ViewBag.Message = "Successfully Registration Done";
              }
          }
          return View(U);
      }
  </code></pre>
  
  <p>Here Is my User Model: </p>
  
  <pre><code>public partial class User
  {
      public User()
      {
          this.Posts = new HashSet&lt;Post&gt;();
          this.PostFeedbacks = new HashSet&lt;PostFeedback&gt;();
          this.ProjectUsers = new HashSet&lt;ProjectUser&gt;();
          this.UserWithdraws = new HashSet&lt;UserWithdraw&gt;();
      }
  
      public decimal user_id { get; set; }
  
      [Required(ErrorMessage = "Please provide username", AllowEmptyStrings = false)]
      public string user_name { get; set; }
  
      [Required(ErrorMessage="Please provide Password", AllowEmptyStrings=false)]
      [DataType(System.ComponentModel.DataAnnotations.DataType.Password)]
      [StringLength(50, MinimumLength = 8, ErrorMessage = "Password must be 8 char long.")]
      public string user_pass { get; set; }
  
      [Compare("user_pass", ErrorMessage = "Confirm password dose not match.")]
      [DataType(System.ComponentModel.DataAnnotations.DataType.Password)]
      public string confirm_user_pass { get; set; }
  
      [Required(ErrorMessage = "Please provide full name", AllowEmptyStrings = false)]
      public string full_name { get; set; }
  </code></pre>