作者：w568273102，来自原文地址 
微信小程序获取小程序页面二维码API接口，通过后台post网址，获取access_token方式，参数{"path": "pages/index/index?query=1", "width": 260},可以获得图片二进制流，直接打印二进制流为乱码

 
该二进制流直接保存成png图片，一下为本人所写的部分核心代码，需要引用using system.net 
/// url 网址 || param 参数

public static string PostMoths(string url, string param) 
{
string strURL = url;
System.Net.HttpWebRequest request;
request = (System.Net.HttpWebRequest)WebRequest.Create(strURL);
request.Method = "POST";
request.ContentType = "application/json;charset=UTF-8";
string paraUrlCoded = param;
byte[] payload;
payload = System.Text.Encoding.UTF8.GetBytes(paraUrlCoded);
request.ContentLength = payload.Length;
Stream writer = request.GetRequestStream();
writer.Write(payload, 0, payload.Length);
writer.Close();
System.Net.HttpWebResponse response;
response = (System.Net.HttpWebResponse)request.GetResponse();
System.IO.Stream s;
s = response.GetResponseStream();
string StrDate = "";
string strValue = "";
byte[] tt = StreamToBytes(s);
//将流保存在c盘test.png文件下
System.IO.File.WriteAllBytes(@"c:\test.png", tt);
}
///将数据流转为byte[]
public static byte[] StreamToBytes(Stream stream)
{
List bytes = new List();
int temp = stream.ReadByte();
while (temp != -1)
{
bytes.Add((byte)temp);
temp = stream.ReadByte();
}
        return bytes.ToArray();
    }

生成的带参数二维码

源代码下载网易云音乐