ASP.NET: Unfamiliar with Interfaces

I’m building a decent sized application in ASP.NET/VB.NET with various objects… I’ve never used interfaces before, and a fellow programmer balked when I mentioned this to him. Can anyone give me a quick overview on how they’re used, what they’re used for, and why I would use them? Maybe I don’t need to use them for this project, but if they would help, I surely would love to try.

Using @font-face with ABCPDF? Or other way of getting fonts into PDF?

We have a large application successfully using ABCPDF.NET with HTML Styled text. We’re accustomed to adding text using fonts not installed in Windows, but stored in files elsewhere in the filesystem — we do this so each user can upload their own fonts and use them with the output. We use the AddFont call to embed the font in the Doc, then reference the font in a tag for HTML Styled text with the AddText call.

Constructing a good search query using system.data.oracleclient

I am constructing a search function in a class to be used by several of our asp pages. The idea is simple, take a search term from the user and query the database for the item. Currently I am doing this the wrong way, which is vulnerable to SQL injection attacks (and ELMAH is in there to save the day if something goes wrong):