订单编号的查询增加（对于要不断删增的表）

public void add()

{

int i_orderID = 0;

string s_Year = string.Format(("{0:D4}"),int.Parse(DateTime.Now.Year.ToString()));

string s_Month = string.Format(("{0:D2}"),int.Parse(DateTime.Now.Month.ToString()));

string s_Day = string.Format(("{0:D2}"),int.Parse(DateTime.Now.Day.ToString()));

DataSet ds=new DataSetDA().selectData("select num from fId");

for (int i = 0; i < ds.Tables[0].Rows.Count;i++ )

{

string str_Date = s_Year + s_Month + s_Day;

string s_Date = ds.Tables[0].Rows[i]["num"].ToString().Substring(0,8);

string s_id = ds.Tables[0].Rows[i]["num"].ToString().Substring(8,4);

if(str_Date.Trim()==s_Date.ToString().Trim())

{

if (int.Parse(s_id) > i_orderID)

{

i_orderID = int.Parse(s_id);

}

}

}

string s_orderID = string.Format(("{0:D4}"),i_orderID + 1);

this.lblfreightID.Text =s_Year + s_Month+s_Day + s_orderID;

new DataSetDA().insert("insert into fId values('"+lblfreightID.Text+"')");

}