用C#實現能讀取文字從非txt文件，像Office文件及pdf文件，它也可以取出像html及xml文件中重要部份，適用於開發文件搜尋方面的功能，非常具參考價值

Simple and very efficient multithreaded web crawler with pipeline based processing written in C#. Contains HTML, Text, PDF, and IFilter document processors and language detection(Google). Easy to add pipeline steps to extract, use and alter informati

Portable Document Filter software