无法获取编码-错误：“”不是受支持的编码名称

Question

I want get html from website using httpwebrequest. But with some website have error " is not a supported encoding name" . Here is my code c#, thanks you.

string url = textBox1.Text;
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
if (response.StatusCode == HttpStatusCode.OK)
{
    Stream receiveStream = response.GetResponseStream();
    StreamReader readStream = null;

    if (response.CharacterSet == null)
    {
        readStream = new StreamReader(receiveStream);
    }
    else
    {

        readStream = new StreamReader(receiveStream, Encoding.GetEncoding(response.CharacterSet));
    }

    string data = readStream.ReadToEnd();
    webBrowser1.Size = new System.Drawing.Size(0, 0);
    htmlview.Size = new System.Drawing.Size(800, 410);
    htmlview.Location = new Point(0, 3);
    htmlview.Margin = new Padding(3);

    htmlview.Text = data;
    response.Close();
    readStream.Close();
}

Answer 1

Most likely, the error occurs due to an invalid/unsupported encoding name. Please refer to here for more information.

A possible solution to avoid such an exception is to check whether response.CharacterSet is a valid encoding name before creating the StreamReader.

Below is a modified version of your code:

            ...

            if (response.StatusCode == HttpStatusCode.OK)
            {
                Stream receiveStream = response.GetResponseStream();
                var encodingInfoNotFound = string.IsNullOrEmpty(response.CharacterSet) || !Encoding.GetEncodings().Any(e => e.Name == response.CharacterSet);
                var readStream = encodingInfoNotFound ? new StreamReader(receiveStream) : new StreamReader(receiveStream, Encoding.GetEncoding(response.CharacterSet));

                string data = readStream.ReadToEnd();
                ...
            }

Hope it helps.