==================================JS===========================================
var user = Ext.Ajax.request({
        method: 'GET',
        url: '/UserAccount/GetUserData',
        success: function (response) {
            user = Ext.util.JSON.decode(response.responseText).results;
            Ext.getCmp('user-name').setHtml(user.Username);
            var image = new Image();
            image.src = 'data:image/png;base64,' + user.ProfilePictureString;
            var e = Ext.getCmp('dashboard-profile-picture');
            e.setSrc(image.src);
        }
    });



==============================================================================



===========================     C# ===========================================
public ActionResult GetUserData()
        {
            if (Session["user"] != null)
            {
                Response.StatusCode = (int)HttpStatusCode.OK;
                var results = new UserRepository().GetUserInfo(Session["user"].ToString());

                return Json(new { results }, JsonRequestBehavior.AllowGet); //TODO: add code for sending back the navigation data
            }
            Response.StatusCode = (int)HttpStatusCode.Unauthorized;
            return Json("Unauthorised access at this point, you must be logged into an account!");
        }




in other c# file




   public User GetUserInfo(string name)
        {
            var _db = base.GetDatabaseConnection();
            if (!String.IsNullOrWhiteSpace(name))
            {
                return _db.SingleOrDefault<User>("WHERE username = @0", name);
            }
            else
            {
                return null;
            }
        }

==============================================================================