title: Tempdata becomes null after redirect to another page
body: <p>When the user successfully login, i'm storing the username in tempdata so i can use it in my _Layout:</p>
  
  <pre><code>TempData["username"] = model.Email.Split('@')[0];
  TempData.Keep("username");
  </code></pre>
  
  <p>on my _Layout:</p>
  
  <pre><code>&lt;li class="nav-item"&gt;                   
       &lt;h5 style="color:white"&gt; Welcome, @TempData["username"]&lt;/h5&gt;                  
  &lt;/li&gt;
  </code></pre>
  
  <p>this actually works on the first load, but if I go to another page, the tempdata turns to null and no username is displaying. How can i keep the username on my _layout?</p>
  
  <p><a href="https://i.stack.imgur.com/ckD4U.png" rel="nofollow noreferrer">Username displaying</a></p>
  
  <p><a href="https://i.stack.imgur.com/MN6Qf.png" rel="nofollow noreferrer">Username not display</a></p>