项目用到的知识点总结,欢迎大家吐槽：

/// 
        /// 转换非yyyy-MM-dd的字符串为DateTime类型        /// 

public static void ConvertDateFormat() {            string orginStr = "test-test-20130607.xls";            string dateStr = orginStr.Split('-')[2].Split('.')[0];            Console.WriteLine(dateStr);            Console.WriteLine(DateTime.ParseExact(dateStr, "yyyyMMdd", System.Globalization.CultureInfo.CurrentCulture).ToString("yyyy-M-d"));        }

相关资料：

 

 

/// 
        /// get the days of currDate minus lastDate;The result is negative is allowed         /// 
        ///         ///         /// 
            private int minusTwoDate(string lastDateStr,string currDateStr) {            DateTime lastDate = Convert.ToDateTime(lastDateStr);            DateTime currDate = Convert.ToDateTime(currDateStr);            return (currDate - lastDate).Days;        }

 

/// 
       /// judage whether cross the month;cross:true;       /// 
       /// the last page recorded       ///        /// 
            private bool whetherCrossMonth(string lastDateStr, string currDateStr)        {            DateTime lastDate = Convert.ToDateTime(lastDateStr);            DateTime currDate = Convert.ToDateTime(currDateStr);            if (currDate.Month == lastDate.Month)//the same month            {                return false;            }            else            {                return true;            }        }

/// 
        /// is last day:true;is not last day:false and return last date of month        /// 
        ///         /// the last day of month or null        /// 
    
     is last day:true;or false
            private bool wetherIsLastDay(string lastDateStr,out string lastDayOfMonth)        {            DateTime lastPageDate = Convert.ToDateTime(lastDateStr);            //first day of month            string lastDay = string.Empty;            DateTime lastDateOfMonth = Convert.ToDateTime(lastPageDate.Year + "-" + lastPageDate.Month + "-" + DateTime.DaysInMonth(lastPageDate.Year, lastPageDate.Month));            if ((lastDateOfMonth-lastPageDate).Days>0)            {                lastDayOfMonth =lastDateOfMonth.ToShortDateString();;                return false;            }// less than The last day of each month            else            {                lastDayOfMonth = lastDay;                return true;            }//         }

sqlite方面：

//sql。如果businessDate字段不格式化为yyyy-MM-dd，则在max()对此字段取值会//出现2013-1-9大于2013-1-10、2013-1-20的情况sqlList.Add(String.Format("insert into test(businessName,businessDate,indb_datetime) values('{0}','{1}','{2}')", EventOrderKeyStr, fileDate.ToString("yyyy-MM-dd"), DateTime.Now.ToString()));//入库环节 DBHelperSqlite dhSqlite = new DBHelperSqlite(); dhSqlite.ExecuteSqlTran(sqlList);

 

dbhelper:

private string dbName = "cmcc2.db";        private string connectionString = "Data Source=cmcc2.db;Pooling=true;FailIfMissing=false";        /// 
        /// if the db is not exists,create it and create the table        /// 
        public DBHelperSqlite()        {            string SQLCreateStr = "CREATE TABLE [cmcc_businesses_info] (businessName nvarchar(50),businessDate nvarchar(10),indb_datetime nvarchar(20))";            #region CASE2            FileInfo fi = new FileInfo(dbName);            if (fi.Exists == false)            {                logger.InfoFormat("db不存在");                //Console.WriteLine("db不存在");                SQLiteConnection.CreateFile(dbName);                logger.InfoFormat("db创建完成");                using (SQLiteConnection conn = new SQLiteConnection(connectionString))                {                    conn.Open();                    using (SQLiteCommand cmd = new SQLiteCommand(SQLCreateStr, conn))                    {                        if (cmd.ExecuteNonQuery() > 0)                        {                            logger.InfoFormat("表创建成功");                            //Console.WriteLine("表创建成功");                        }                    }                }            }            #endregion        }//ctor        /// 
        /// 执行多条SQL语句，实现数据库事务。        /// 
        /// 多条SQL语句                public void ExecuteSqlTran(IList
    
      SQLStringList)        {            using (SQLiteConnection conn = new SQLiteConnection(connectionString))            {                conn.Open();                SQLiteCommand cmd = new SQLiteCommand();                cmd.Connection = conn;                SQLiteTransaction tran = conn.BeginTransaction();                cmd.Transaction = tran;                try                {                    for (int n = 0; n < SQLStringList.Count; n++)                    {                        string strsql = SQLStringList[n].ToString();                        if (strsql.Trim().Length > 1)                        {                            logger.Debug(strsql);                            cmd.CommandText = strsql;                            cmd.ExecuteNonQuery();                        }                    }                    tran.Commit();                }                catch (System.Data.SQLite.SQLiteException ex)                {                    logger.Error(ex);                    tran.Rollback();                    //throw new Exception(ex.Message);                }            }        }//trans
    

SubString函数使用时一个隐藏的“雷”：

/// 
        /// str.Substring(startIndex,length)如果length大于str的长度，就会报错        /// 
        public static void SubstringTest2()        {            string str = "4.333";            string[] r = str.Split('.');            if (r.Length == 2)            {                if (r[1].Length > 4)                {                    r[1] = r[1].Substring(0, 4);                }                Console.WriteLine(r[0] + "." + r[1]);            }        }