public List<BusResordModel> GetAll()
        {
            try
            {

                List<BusResordModel> list = new List<BusResordModel>();
                using (SqlDataReader dr = sqlH.ExecuteReader("GetAllBusRecord", CommandType.StoredProcedure, null))
                {
                    while (dr.Read())
                    {

                        BusResordModel busM = new BusResordModel();
                        busM.CardNo = dr["cardNo"].ToString();
                        busM.UserName = dr["userName"].ToString();
                        busM.BusNo = dr["busNo"].ToString();
                        busM.BusType = dr["busType"].ToString();
                        try
                        {
                            busM.InTime = Convert.ToDateTime(dr["inTime"]);
                            if (busM.InTime==null)
                            {
                                busM.InTime = Convert.ToDateTime("");
                            }
                        }
                        catch (Exception)
                        {


                        }
                        busM.InAddr = dr["inAddr"].ToString();
                        try
                        {
                            [color=#0000FF]busM.OutTime = Convert.ToDateTime(dr["outTime"]);[/color]                            if (busM.OutTime ==Convert.ToDateTime("0001-1-1 0:00:00"))
                            {
                                busM.OutTime = Convert.ToDateTime("");
                            }
                        }
                        catch (Exception)
                        {


                        }
                        busM.OutAddr = dr["outAddr"].ToString();
                        busM.TotalTime = Convert.ToInt32(dr["totalTime"]);
                        busM.Price = dr["price"].ToString();
                        busM.Operater = dr["operater"].ToString();
                        busM.Picture = dr["picture"].ToString();
                        busM.Photo = dr["photo"].ToString();
                        busM.Guid = dr["guid"].ToString();
                        list.Add(busM);
                    }
                    return list;
                }
            }
            catch
            {
                return null;
            }

        }

if(dr["outTime"]!=null)
{
  busM.OutTime=Convert.ToDateTime(dr["outTime"]);
}
else
{
    busM.OutTime=Convert.ToDateTime("2010-01-01");//设置个默认值啊
}

------解决方案--------------------

//有些数据库字段取出来，只判断是不是null是没用的，有可能是DBNull类型
if(dr["inTime"]==null || dr["inTime"]!==DBNull.Value)
{
   //如果空就赋默认值
   busM.InTime =DateTime.Now;
}
else
{
   try
  {
    busM.InTime =Convert.ToDateTime(dr["inTime"]);
  }
  catch (Exception)
  {
     //如果错误就赋默认值
     busM.InTime =DateTime.Now;
   }

}

------解决方案--------------------
C# code
class BusResordModel{
    privaite DateTime? _outTime = null;
    public DateTime? outTime { get{....} set{....} }  //使用? 表示此属性允许null值。在程序中可判断： if(outTime.HasValue) outTime.Value.....

    .....
}

.......
object obj = dr["outTime"];
if(obj != null && obj != DBNull.Value) ....outTim