How to retrieve last three passwords of a user from active directory?

I am implementing a Change password screen for the user and there is a requirement that changed password 开发者_StackOverflow中文版should not be same as last three passwords of a user.Can i do that in c# using directory entry and directory searcher.

Use Active Directory: http://technet.microsoft.com/en-us/library/cc875814.aspx

Unless you store the passwords in a program database you wont be able to see previous passwords in AD. Go the proper approach and use AD for this task.