C# 编码问题？

我想从网络上获取一张图片，并将其转换为字节数组。但是阅读回答时有点不对劲。我怀疑这是由编码模式引起的

        WebRequest request = WebRequest.Create("http://www.waterfootprint.org/images/gallery/original/apple.jpg");
        request.Method = "GET";
        request.Timeout = 10000;
        using (WebResponse response = request.GetResponse())
        {
            Stream stream = response.GetResponseStream();
            Encoding encoding = Encoding.UTF8;
            StreamReader streamReader = new StreamReader(stream, encoding);

            string responseBody = streamReader.ReadToEnd(); //always invalid characters here
            streamReader.Close();
            stream.Dispose();
            byte[] buffer = Convert.FromBase64String(responseBody); 
        }

我尝试过其他编码方式，如UTF7、Unicode等，但都是徒劳的。有人能告诉我为什么吗？谢谢

        WebRequest request = WebRequest.Create("http://www.waterfootprint.org/images/gallery/original/apple.jpg");
        request.Method = "GET";
        request.Timeout = 10000;
        using (WebResponse response = request.GetResponse())
        {
            Stream stream = response.GetResponseStream();
            Encoding encoding = Encoding.UTF8;
            StreamReader streamReader = new StreamReader(stream, encoding);

            string responseBody = streamReader.ReadToEnd(); //always invalid characters here
            streamReader.Close();
            stream.Dispose();
            byte[] buffer = Convert.FromBase64String(responseBody); 
        }

    StreamReader streamReader = new StreamReader(stream, encoding);

是一种文本阅读器，它以特定编码从字节流中读取字符

        WebRequest request = WebRequest.Create("http://www.waterfootprint.org/images/gallery/original/apple.jpg");
        request.Method = "GET";
        request.Timeout = 10000;
        using (WebResponse response = request.GetResponse())
        {
            Stream stream = response.GetResponseStream();
            Encoding encoding = Encoding.UTF8;
            StreamReader streamReader = new StreamReader(stream, encoding);

            string responseBody = streamReader.ReadToEnd(); //always invalid characters here
            streamReader.Close();
            stream.Dispose();
            byte[] buffer = Convert.FromBase64String(responseBody); 
        }

StreamReader是为字符而设计的 输入特定的编码， 而流类是设计的 用于字节输入和输出。使用 StreamReader，用于读取 来自标准文本文件的信息

        WebRequest request = WebRequest.Create("http://www.waterfootprint.org/images/gallery/original/apple.jpg");
        request.Method = "GET";
        request.Timeout = 10000;
        using (WebResponse response = request.GetResponse())
        {
            Stream stream = response.GetResponseStream();
            Encoding encoding = Encoding.UTF8;
            StreamReader streamReader = new StreamReader(stream, encoding);

            string responseBody = streamReader.ReadToEnd(); //always invalid characters here
            streamReader.Close();
            stream.Dispose();
            byte[] buffer = Convert.FromBase64String(responseBody); 
        }

在您接收原始字节的情况下，您需要直接使用

流

，使用

二进制读取器

或更高级别的抽象

        WebRequest request = WebRequest.Create("http://www.waterfootprint.org/images/gallery/original/apple.jpg");
        request.Method = "GET";
        request.Timeout = 10000;
        using (WebResponse response = request.GetResponse())
        {
            Stream stream = response.GetResponseStream();
            Encoding encoding = Encoding.UTF8;
            StreamReader streamReader = new StreamReader(stream, encoding);

            string responseBody = streamReader.ReadToEnd(); //always invalid characters here
            streamReader.Close();
            stream.Dispose();
            byte[] buffer = Convert.FromBase64String(responseBody); 
        }

        byte[] buffer = Convert.FromBase64String(responseBody); 

您得到的流不是base64编码的-它是一个纯图像字节流，因此只需直接分配字节，最简单的方法是使用：

        WebRequest request = WebRequest.Create("http://www.waterfootprint.org/images/gallery/original/apple.jpg");
        request.Method = "GET";
        request.Timeout = 10000;
        using (WebResponse response = request.GetResponse())
        {
            Stream stream = response.GetResponseStream();
            Encoding encoding = Encoding.UTF8;
            StreamReader streamReader = new StreamReader(stream, encoding);

            string responseBody = streamReader.ReadToEnd(); //always invalid characters here
            streamReader.Close();
            stream.Dispose();
            byte[] buffer = Convert.FromBase64String(responseBody); 
        }

---

通常在您必须以ASCII文本形式传输二进制数据（即作为XML CData元素或SOAP的一部分）时使用，但如果您希望通过HTTP传输二进制文件（即图像），则不使用。

它返回为二进制，而不是base-64编码。例如，如果我更改代码以直接从响应流创建图像，我会看到它出现在PictureBox控件中

        WebRequest request = WebRequest.Create("http://www.waterfootprint.org/images/gallery/original/apple.jpg");
        request.Method = "GET";
        request.Timeout = 10000;
        using (WebResponse response = request.GetResponse())
        {
            Stream stream = response.GetResponseStream();
            Encoding encoding = Encoding.UTF8;
            StreamReader streamReader = new StreamReader(stream, encoding);

            string responseBody = streamReader.ReadToEnd(); //always invalid characters here
            streamReader.Close();
            stream.Dispose();
            byte[] buffer = Convert.FromBase64String(responseBody); 
        }

    private void button1_Click(object sender, EventArgs e)
    {
        WebRequest request = WebRequest.Create("http://www.waterfootprint.org/images/gallery/original/apple.jpg");
        request.Method = "GET";
        request.Timeout = 10000;
        using (WebResponse response = request.GetResponse())
        {
            Stream stream = response.GetResponseStream();
            Bitmap b = (Bitmap)Bitmap.FromStream(response.GetResponseStream());
            pictureBox1.Image = b;
        }
    }

---

但是如果在服务器端，图像只是以Base64编码返回：

returnconvert.FromBase64String（imageString）

这会很奇怪-但是假设您可以使用

wc.DownloadString（）

获取字符串，然后使用

Convert.FromBase64String（）

将其转换回字节数组。