If you want to do a query against AD (active directory) there are several ways to do it – but (only) one proper way like usual.

The DirectorySearcher class has a ‘filter’ property that allows you to filter the returned results – oppose to you having to test each property in code. The syntax of this filter is a bit tricky (ok a lot…)

It took me a while to figure out how to properly set up a filter to do more complex queries – like when you have multiple things to filter by including ‘and’s and ‘or’s. Anyway, I found a good reference here: Search Filter Syntax.

It explains the syntax plus give some examples. It also list some special characters plus explain how to use ‘wildcards’.

Happy searching…