I need to get the raw request string. Below is an example of the http request sent to the Controller. Actually, I need Post data (last line). How can I get that?
At that point the stream has already been read to the end. You need to set the position of the InputStream back to the beginning before you can read it yourself.
Request.InputStream.Position = 0;
var input = new StreamReader(Request.InputStream).ReadToEnd();