How can I achive what I described in the title? (IE addon to intercept and change HTTP and HTTPS form data before sending it to the server)
Welcome to MSDN forum.
I would like to provide your as a convenience with this program: "Fiddler"
"FiddlerCore allows you to integrate HTTP/HTTPS traffic viewing and modification capabilities into your .NET application, without any of the Fiddler UI."
This site contains the tutorial of developing with Fiddler:http://fiddler.wikidot.com/fiddlercore
Hope these can help you.
Damon Zheng [MSFT]
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