为什么这个字符串不是日期

Question

我不明白我在哪里犯了这个错误 System.FormatException: 'String was not recognized as a valid DateTime'UserDOB 工作正常，但 DateTimeStamp 不工作。while (reader.Read()){    list1.Add(new User()    {        UserId = Convert.ToInt32(reader["UserId"]),        UserName = reader["UserName"].ToString(),        UserSurname = reader["UserSurname"].ToString(),        UserPassportNo = reader["UserPassportNo"].ToString(),        UserAccessPoint = reader["UserAccessPoint"].ToString(),        UserAccessType = reader["UserAccessType"].ToString(),        UserDOB = DateTime.Parse(reader["UserDOB"].ToString()),        DateTimeStamp = DateTime.Parse(reader["DateTimeStamp"].ToString()),    });}我的model.DatabaseConnectionpublic class User{    public int UserId { get; set; }    public string UserName { get; set; }    public string UserSurname { get; set; }    public string UserPassportNo { get; set; }    public string UserAccessPoint { get; set; }    public string UserAccessType { get; set; }    public System.DateTime UserDOB { get; set; }    //[DisplayFormat(ApplyFormatInEditMode = true, DataFormatString = "{0:MM/dd/yyyy}")]    public System.DateTime DateTimeStamp { get; set; }}