主线程create一个ConcurrentQueue ，然后用三个子线程往里面写数，主线程建timer检查ConcurrentQueue>某值，存数据库，存进多少就清ConcurrentQueue多少

代码 ：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Threading;
using System.Data;
using System.Data.SqlClient;
using System.Data.SqlTypes;
using System.Collections.Concurrent;

namespace MultiThreadInserDataIntoList
{
    public class CommandDetail
    {
        public string sessionIP { get; set; }
        public string sessionID { get; set; }
        public string commandName { get; set; }
        public DateTime cmd_recv_time { get; set; }
        public DateTime cmd_reply_time { get; set; }
        public string cmd_content { get; set; }
        public string reply_content { get; set; }
        public string err_reason { get; set; }
    }

    class Program
    {
        static System.Threading.Timer _timer;
        static ConcurrentQueue<CommandDetail> CommandDetailList = new ConcurrentQueue<CommandDetail>();
        


        static void Main(string[] args)
        {
            Task task1 = Task.Factory.StartNew(() => doStuff(CommandDetailList));
            Task task2 = Task.Factory.StartNew(() => doStuff(CommandDetailList));
            Task task3 = Task.Factory.StartNew(() => doStuff(CommandDetailList));
            _timer = new System.Threading.Timer(new TimerCallback(JobCallBack), null, 0, 1000);
            Console.ReadLine();


        }
        //
        static void doStuff(object o1)
        {
            ConcurrentQueue<CommandDetail> typed = (ConcurrentQueue<CommandDetail>)o1;
            CommandDetail cst = new CommandDetail { cmd_recv_time = DateTime.Now, cmd_reply_time = DateTime.Now, reply_content = "111", cmd_content="111", commandName="GETNAP", sessionID="111", sessionIP="111" };

            for (int i = 0; i < 300; i++)
            {
                Thread.Sleep(100);
                typed.Enqueue(cst);
                //Console.WriteLine("add one row to list");
            }
        }
        //
        static void JobCallBack(object state)
        {
            int iEffect = 0;
            if (CommandDetailList.Count >= 100)
            {
                //var items = CommandDetailList.Take(100);
                
                //Console.WriteLine("DB call with {0} Items",items.Count());
                
                using (SqlConnection conn = new SqlConnection("Data Source=DESKTOP-DQPC13K;Initial Catalog=SmalllSmartBilling;Integrated Security=True;"))
                {
                    try
                    {
                        conn.Open();

                        SqlCommand comm = conn.CreateCommand();
                        comm.CommandText = "sp_InsertRequestReply";
                        comm.CommandType = System.Data.CommandType.StoredProcedure;
                        comm.CommandTimeout = 300;


                        comm.Parameters.Add(new SqlParameter()
                        {
                            ParameterName = "@TVP",
                            SqlDbType = SqlDbType.Structured,
                            Value = GetDataTableParam(CommandDetailList)
                        });

                        comm.Parameters.Add(new SqlParameter()
                        {
                            ParameterName = "@result",
                            SqlDbType = SqlDbType.Int,
                            Direction = ParameterDirection.Output,
                            Size = 4
                        });

                        comm.Parameters.Add(new SqlParameter()
                        {
                            ParameterName = "@errormsg",
                            SqlDbType = SqlDbType.VarChar,
                            Direction = ParameterDirection.Output,
                            Size = 1000
                        });

                        iEffect = comm.ExecuteNonQuery();
                        Console.WriteLine("this time total insert {0} rows", iEffect);
                    }
                    catch (Exception uep)
                    {
                        return;
                    }
                }   //using



                //clear
                //Console.WriteLine("before clear,List have {0} rows", CommandDetailList.Count);

                //CommandDetail localValue;
                //int iRety = 100;
                //while (iRety > 0)
                //{
                //    CommandDetailList.TryDequeue(out localValue);
                //    iRety--;
                //}
                //Console.WriteLine("success remove {0} rows", iRety);

                Remove(CommandDetailList, iEffect);

            }   // if > 100
            else
            {

                Console.WriteLine("remain {0} rows", CommandDetailList.Count);
            }
        }

        private static void Remove(ConcurrentQueue<CommandDetail> q, int count)
        {
            CommandDetail commandDetail;
            Enumerable.Range(1, count).ToList().ForEach(n => q.TryDequeue(out commandDetail));
        }


        //
        static DataTable GetDataTableParam(IEnumerable<CommandDetail> People)
        {
            //define the table and rows (the rows match those in the TVP)
            DataTable peopleTable = new DataTable();
            peopleTable.Columns.Add("Session_IP", typeof(string));
            peopleTable.Columns.Add("Session_ID", typeof(string));
            peopleTable.Columns.Add("CommandName", typeof(string));

            peopleTable.Columns.Add("Request_Recv_Time", typeof(DateTime));
            peopleTable.Columns.Add("Request_reply_Time", typeof(DateTime));

            peopleTable.Columns.Add("Request_Content", typeof(string));
            peopleTable.Columns.Add("Reply_Content", typeof(string));
            peopleTable.Columns.Add("Err_Reason", typeof(string));


            foreach (CommandDetail p in People)
            {
                // add a row for each person
                DataRow row = peopleTable.NewRow();
                //row["clsCarrierID"] = p.clsCarrierID;
                //row["clsis_supplier"] = p.clsis_supplier;
                row["Session_IP"] = p.sessionIP;
                row["Session_ID"] = p.sessionID;
                row["CommandName"] = p.commandName;

                row["Request_Recv_Time"] = p.cmd_recv_time;
                row["Request_reply_Time"] = p.cmd_reply_time;
                row["Request_Content"] = p.cmd_content;
                row["Reply_Content"] = p.reply_content;
                row["Err_Reason"] = p.err_reason;

                peopleTable.Rows.Add(row);
            }
            return peopleTable;


        }

        //
    }
}

注：一开始用的是 List<> , 但发现 不能保证线程安全，后来在 stackoverflow 提问， 改用 ConcurrentQueue ，队列的特征是 front delete 的同时， 可以在 tail insert ，

足以保证thread safe 

原帖网址 ： http://stackoverflow.com/questions/43905150/issues-when-use-a-timer-to-save-listclass-into-db-and-the-list-is-writing-by