问题
The HttpClientHandler can be used as a parameter when creating a HttpClient object, but after that there doesn't seem to be any way to access the handler without keeping a reference to it.
Dim Handler as New HttpClientHandler
Handler.CookieContainer = Cookies
Handler.Proxy = Proxy
Handler.UseProxy = True
Handler.AutomaticDecompression = DecompressionMethods.GZip Or DecompressionMethods.Deflate
Dim Client as New HttpClient(Handler, True)
Am I able to change the properties of a handler of an existing client object? For example, change the Proxy or the AutoRedirect. Would I have any issues doing this while other HttpRequestMessages are currently being processed by the client?
回答1:
Yes, you can. The key is to change the object and not the property of the httpclient. Remember OOP 101.
Point the property to the same object but change the contents of that object.
Dim Handler As New HttpClientHandler
Dim proxy As New WebProxy()
Dim urlBuilder As New System.UriBuilder
Handler.Proxy = proxy
Handler.UseProxy = True
Handler.AutomaticDecompression = DecompressionMethods.GZip Or DecompressionMethods.Deflate
Dim Client As New HttpClient(Handler, True)
urlBuilder.Host = "124.161.94.8"
urlBuilder.Port = 80
proxy.Address = urlBuilder.Uri
Dim response As String = Await Client.GetStringAsync("http://www.ipchicken.com")
urlBuilder.Host = "183.207.228.8"
urlBuilder.Port = 80
proxy.Address = urlBuilder.Uri
response = Await Client.GetStringAsync("http://www.ipchicken.com")
回答2:
After further testing it seems it is not possible, an exception is thrown when I attempt to modify the properties of the HttpClientHandler. A new instance of HttpClient is required.
来源：https://stackoverflow.com/questions/25795777/can-i-change-the-properties-of-a-httpclienthandler-after-the-httpclient-has-been