我正在玩一個簡單的f#示例this nice tutorial。並遇到這個非常奇怪的錯誤。在向webrequest添加代理後,它告訴我類型WebProxy與預期類型IWebProxy不兼容。這有點奇怪,爲什麼我的C#錘子在F#中沒有工作?這個表達式預計有IWebProxy類型,但這裏有類型WebProxy
我在這裏做錯了什麼?
let downloadUrlToFile url file =
let req = WebRequest.Create(Uri(url))
req.Proxy = new WebProxy("127.0.0.1", 444)
use res = req.GetResponse()
use stream = res.GetResponseStream()
use reader = new IO.StreamReader(stream)
let timestamp = DateTime.UtcNow.ToString("yyy-MM-dd")
let path = sprintf "%s.%s.html" file timestamp
use writer = new IO.StreamWriter(path)
writer.Write(reader.ReadToEnd())
printfn "done loading %s to %s" url file
錯誤消息
This expression was expected to have type
IWebProxy
but here has type
WebProxy