need to search for social security number in thousands of documents (.doc,.docx,.pdf) in C#

Which is the best way to access the documents (opening and reading only text) so that searching is faster. I have already tried using Microsoft office word object to open and get the text by creating a word application and opening the files. I cant even go w开发者_开发问答ith threading because either i need to create only one word application which wont help me in threading and if i create word application in each thread the system cant handle it. How do you suggest me to go.

Thanks in advance

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Ah... go back to reading the documentation of your operating system. FOr quite some time (i.e. many many years) there is an indexing and search system there that actually a lot of things can hook in (if you install the proper filters, downloadable from microsoft, adobe etc.).

This creates a full text index that then has an API to search. A LOT more efficient for repeatedly searching a large number of documents.