this.selectStr="insert into RoomType values("+"'"+typename+"',"+area+","+bednum+","+price+","+aircondition+","+telephone+","+tv+","+toilet+")";
this.selectStr="update RoomType set Area="+area+","+"BedNum="+bednum+","+"Price="+price+","+"Toilet="+toilet+","+"AirCondition="+aircondition+","+"Television="+tv+","+"Phone="+telephone+" where RoomTypeName="+"'"+typename+"'";

这是Sql语句规定的，不是C#才这样写！