c# 簡單做流水號的方法

註我的流水號是 (民國年三碼) + 月月 + 三碼流水號
所以後面有-1911
這是做月份的方式以此類推後面可以有日的

//取得流水號 
string Sql1 = " select top 1 convert(int,substring(CX_Order_No,6,3)) as maxNo from QuoteList where substring(CX_Order_No,1,5)=@yyyMM  order by convert(int,substring(CX_Order_No,6,3)) desc ";
SqlCommand cmd1 = new SqlCommand(Sql1, conn);
decimal myyy = PublicClass.ToDecimal(DateTime.Now.Year.ToString() )- 1911;           
myyyyMM = myyy.ToString() + int.Parse(DateTime.Now.Month.ToString()).ToString("00"); 
cmd1.Parameters.AddWithValue("@yyyMM", myyyyMM);
DataTable dt1 = new DataTable();
SqlDataAdapter da1 = new SqlDataAdapter(cmd1);
da1.Fill(dt1);

if (dt1.Rows.Count > 0)
{
myyyyMM = myyyyMM + int.Parse(  ( PublicClass.ToDecimal(dt1.Rows[0]["maxNo"].ToString()) + 1).ToString()).ToString("000");//有時給他加1
}
else
{
myyyyMM = myyyyMM + "001";//沒有時就給他001
}