I have a c# windows form application with Webbrowser control. For the URL that I have, need to get the POST data. How do I get this? SHould this be coded inside the webbrowser.Navigating event?

From this article, in VB.NET but also applies to C#:

That functionality isn't exposed by the .NET WebBrowser control. Fortunately, that control is mostly a wrapper around the 'old' control. This means you can subscribe to the BeforeNavigate2 event... using something like the following (after adding a reference to SHDocVw to your project):

Dim ie = DirectCast(WebBrowser1.ActiveXInstance, SHDocVw.InternetExplorer)
AddHandler ie.BeforeNavigate2, AddressOf WebBrowser_BeforeNavigate2