c# - ContentType 中提供的字符集无效

Question

我用 async await 写了一些简单的代码，但是当我尝试运行它时，编译器抛出一个 System.InvalidOperationException。

完整的错误信息是:

Unhandled Exception: System.InvalidOperationException: The character set provided in ContentType is invalid. Cannot read content as string using an invalid character set.

System.ArgumentException: 'ISO-8859-2' is not a supported encoding name. For information on defining a custom encoding, see the documentation for the Encoding.RegisterProvider method.

代码:

class Program
{
    static async Task Main(string[] args) => await asyncDoItAsync();

    private static async Task<string> asyncDoItAsync()
    {
        HttpClient client = new HttpClient(); 
        Task<string> url = client.GetStringAsync("http://google.pl");

        while(!url.IsCompleted)
        {
            WhenWaiting();
        }

        string url_length  = await url;

        return url_length;
    }

    private static void WhenWaiting()
    {
        Console.WriteLine("Waiting ...");
        Thread.Sleep(90);
    }
}

Answer 1

GetStringAsync 似乎不支持响应中的 iso-8859，您基本上无能为力。所以你需要从 GetAsync 开始。请务必清除现有 header ，否则它可能仍会失败。以下适用于您提供的网址(尽管我使用的是 ISO-8859-1 而不是 2):

var client = new HttpClient();
client.DefaultRequestHeaders.Clear();
string s = null;
var result = await client.GetAsync("http://google.pl");
using (var sr = new StreamReader(await result.Content.ReadAsStreamAsync(), Encoding.GetEncoding("iso-8859-1")))
{
     s = sr.ReadToEnd();
}