WebClient 设置标头 [英] WebClient set headers

问题描述

如何在 webClient 类中设置标题?我试过了:

How I can set a header in the webClient class? I tried:

client.Headers["Content-Type"] = "image/jpeg";

抛出 WebException

我的代码:

WebClient client = new WebClient();
client.Headers.Set("Content-Type", "image/png");
client.Headers.Set("Content-Length", length);
client.Headers.Add("Slug", name);
NameValueCollection nvc = new NameValueCollection();
nvc.Add("file", FileContents);

Byte[] data = client.UploadValues(url, nvc);
string res = Encoding.ASCII.GetString(data);
Response.Write(res);

推荐答案

如果header已经存在:

If the header already exists:

client.Headers.Set("Content-Type", "image/jpeg");

如果是新标题:

client.Headers.Add("Content-Type", "image/jpeg");

此外，您可能会遇到错误，因为您尝试设置标题太晚了.发布您的例外情况，以便我们通知您.

Also, there is a chance that you are getting an error because you are trying to set the headers too late. Post your exception so we can let you know.

更新

看起来对 WebClient 类的Content-Type"标头有一些奇怪的限制.考虑使用 client.Download 方法(DownloadData、DownloadFile 等)

看看在 webclient 上使用UploadFile"方法是否有效，而不是手动进行.它返回响应体字节[].

See if using the "UploadFile" method on webclient works rather than doing it manually. It returns the respose body byte[].

如果您仍然遇到 WebClient 问题，请尝试使用普通的旧 HttpRequest/HttpWebRequest.

If you continue to have issues with the WebClient, try justing using a plain old HttpRequest/HttpWebRequest.

这篇关于WebClient 设置标头的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！