Google "automate outlook .net" and you'll find lots of examples
Office C# app automates Outlook (CSAutomateOutlook) sample in C# for Visual Studio 2010[
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You're going to end up with annoying security pop-ups though, it's not going to be "seamless". The alternative is to actually unsderstand how email works and realise that Outlook is merely a desktop application that shows what is in an email account. If the mails are in an account on Exchange or a mail server, then rather than automating Outlook you should simply access the emails from the mail server they are on using POP3 or IMAP.
Lastly if you are intending to do this from an asp.net website then don't bother, it's not going to work.