GET request with space in QueryString crashes code

Simply put my code is working fine and returning JSON from GET requests, but when there is a space in one of the value pairs of the QueryString the Service shuts down. Even when debugging in the IDE no exception is thrown, although, using Fiddler to perform the GET request I开发者_Python百科 get back a "HTTP Error 400 - Bad Request" - probably because the server's just shut down (the Visual Studio development Server).

Spaces aren't a legal part of the querystring, and should be replaced with a + (plus sign)