Question : Incremental search listbox w/ SQL Server w/ ability to append records to the serached table

Hi, I am looking for C# code to use a incremental search listbox on my ASP.NET website.
This listbox would display matches to the users input as they type,  seen on many sites.

I found this:  http://www.asp.net/ajax/videos/how-do-i-use-the-aspnet-ajax-listsearch-extender

But in addition I would like to:
1) pull the data, for the list, from a sql database
      1a) what is the maximum number of records that should be pulled?
2) if the user types in a non-matching item,  have that item appended into the searched table.

Thanks

Answer : Incremental search listbox w/ SQL Server w/ ability to append records to the serached table

Is this any use?

http://www.c-sharpcorner.com/UploadFile/raj1979/AutoComplete02142008113654AM/AutoComplete.aspx