在Windows Service中按特定时间间隔发送电子邮件

Question

I am using Visual Studio 2010 and Database Sql Server 2010.

I have Created a Window Service which must sent email's when time interval occurs (EMAIL_SENT_TIME)

My Database Contains this columns

    Tracker_Id bigint 
,EMAIL_SENT_TIME bigint --this contains interval in which the email must be fired 1800,3600,7200 etc, 
    Last_check datetime --the previous check datetime,
    next_check datetime --the next check datetime

Assume table contains this date tracker_Id | EMAIL_SENT_TIME | Last_check | next_check
100097 1800 datetime nextdatetime
100098 3600 datetime nextdatetime
100099 7200 datetime nextdatetime
100100 1800 datetime nextdatetime

1800 means 30 mins, 3600 means 1 hours etc.

I want to send email after 30 mins those EMAIL_SENT_TIME are 1800 and so on.

how to solve this problem....

Answer 1

Can the EMAIL_SENT_TIME column change for each record or is it a constant? One of the easiest ways to do something on an interval is the System.Threading.Timer class. The first parameter is the callback function (in this case to send an email every time the interval elapses), then state data (this could possibly contain information you want to insert into each email, offset time, and the last is the interval. This class also allows you to change the interval while the Timer is running if your database EMAIL_SENT_TIME value changes.

Timer timer = new Timer((x) => SendEmail(), null, 0, EMAIL_SENT_TIME * 1000).

In the SendEmail() function you can record the current DateTime.Now in the Last_Check time column. You don't really need Next_Check because you can always add last check plus interval to get that value.

System.Threading.Timer