.Net WebClient fails for very long query string

Question

I'm trying to connect to a oracle webmethods web service which takes an xml file as a query string. The query string is very long, sometimes around 400K chars. WebClient, HttpWebRequest etc. does not support such long query strings. Does it have any alternative? I've no control over the design of the Web services and are merely consumers like a few others. Interesting thing is that if I copy paste the entire data on firefox address bar it goes through and I received acknowledgements also that the entire file content is received at the other end.

Answer 1

See this here: What is the maximum possible length of a query string?

Different software appears to accept different maximum length query strings, which is why I would guess firefox works according to that answer.

I would suggest contacting the makers of the API to allow POST queries, that way you could have larger payloads and it would be more secure when using SSL.