Question

I am building a website now for a library and i need to check every day at the same time if there are people who need to return their books in the next five days and to send them a reminder via email.

My question is what will be the correct way to do that?

What i need to accomplish is when the specific time of day comes i need to run an sql stored procedure and check either through visual studio 2010 or any other way if the stored procedure has returned any results to which i need to email.

Is there a way to maybe check the system time constantly on C# and not as a triggered event?

Answer 1

I’d image the simplest way to do this would be by creating a new job in the SQL Server Agent to call your stored procedure every day, rather than trying to achieve this in an application you’ve written.

See the following link for more information on creating SQL Jobs

Edit – Sorry, I really shouldn’t try to answer SO posts while doing other work too. I completely missed the fact you wanted to send off emails, and got it into my head that you wanted to report overdue records on screen. Duh.

To send off overdue emails at a certain time every day, i’d guess a windows service would certainly do the job, but seems a little over the top, and you’d need to have full control over the server it’s running on.

You could instead set up a scheduled task to call a sendOverdueMail.aspx web page every day to do the work perhaps? Like this

Obviously there is the SQL Server Agent emailing option too, although I’m not sure how much control you’d have over the format of the emails that would produce.

Finally, this tutorial steps through creating a scheduled task type effect, by hooking into cache expiry events on an ASP.net server, which then allow you to call your emailing code.

private const string DummyCacheItemKey = "GagaGuguGigi";
protected void Application_Start(Object sender, EventArgs e)
{
    RegisterCacheEntry();
}

private bool RegisterCacheEntry()
{ 
    if( null != HttpContext.Current.Cache[ DummyCacheItemKey ] ) return false;

        HttpContext.Current.Cache.Add( DummyCacheItemKey, "Test", null, 
        DateTime.MaxValue, TimeSpan.FromMinutes(1), 
        CacheItemPriority.Normal,
        new CacheItemRemovedCallback( CacheItemRemovedCallback ) );

    return true;
}


public void CacheItemRemovedCallback( string key, 
        object value, CacheItemRemovedReason reason)
{
    Debug.WriteLine("Cache item callback: " + DateTime.Now.ToString() );

    // send reminder emails here
    DoWork();
}