What kind of encoding is this?

What kind of encoding do you 开发者_StackOverflowuse to encode http:// as http%253A%252F%252F

HttpUtility.UrlEncode gives http%3a%2f%2f

What you're looking at is text that has been passed through UrlEncode twice.

The second time changes the % symbols to %25.

It's unusual to pass an entire URL through UrlEncode anyway, unless you are passing it as a parameter in another URL (for redirection, for instance).

It looks like UrlEncode was called twice, encoding the literal % as %25 (which is the correct result, by the way).