1 1  //把登陆用户名存到cookies中
2 2 HttpCookie cook = new HttpCookie("cookusername", UserName.ToString());    
3 3 Response.Cookies.Add(cook);

<a href="#" class="dropdown-toggle" data-toggle="dropdown" role="button"
                           aria-expanded="false">
                            <i class="fa fa-user-o fa-fw"></i>
                            @if (Request.Cookies["cookusername"]!= null)
                            {
                                @Request.Cookies["cookusername"].Value;
                            }                                              
                            <span class="caret"></span>
                        </a>

1  //登陆成功把用户名存入session
2 Session["username"] = UserName.ToString();

1 <a href="#" class="dropdown-toggle" data-toggle="dropdown" role="button"
2                            aria-expanded="false">
3                             <i class="fa fa-user-o fa-fw"></i>
4                             @if (Session["username"]!= null)
5                             {
6                                 @Session["username"].ToString();
7                             }                                              
8                             <span class="caret"></span>
9                         </a>

<system.web>
<sessionState mode="InProc" timeout="30"></sessionState>  <!--session过期时间设置-->
</system.web>