(C#)调用Webservice，提示远程服务器返回错误(500)内部服务器错误

 因为工作需要调用WebService接口，查了下资料，发现添加服务引用可以直接调用websevice

参考地址：https://www.cnblogs.com/peterpc/p/4628441.html

如果不添加服务引用又怎么做呢？于是又去查看怎么根据http协议调用webservice并做了个无参接口测试，如下：

但一做有参的接口调用就提示500错误（远程服务器返回错误(500)内部服务器错误），查了半天资料，大多数都说是ContentType = "application/x-www-form-urlencoded; charset=UTF-8"; 改成ContentType = "text/html";或者在<@Page..%>中设置 ValidateRequest="false" 即可（这里无需修改Content-type）。结果还是报一样的错误。最后再https://www.jb51.net/article/120015.htm中发现参数是要拼接一下的 (param = HttpUtility.UrlEncode("param1") + "=" + HttpUtility.UrlEncode(num1) + "&" + HttpUtility.UrlEncode("param2") + "=" + HttpUtility.UrlEncode(num2);) ,这样传递int、string类型的参数都没问题。业务要求传递的是图片二进制转化的string类型数据，结果还是报500错误。经过调试对比发现图片二进制数据转化成的string类型数据没有根据url形式传递，而是带有特殊符号的，知道问题所在就好办了，把它转化成有效的url传输数据就行,.net也有现成的封装方法：HttpServerUtility.UrlTokenEncode(bmpBytes)，这样500错误也解决了。

测试代码如下：

  protected void Page_Load(object sender, EventArgs e)
        {
            Bitmap bmp = new Bitmap(System.Drawing.Image.FromFile("C:/Users/TYTD/Desktop/测试样本/ch_DJI_279.jpg"));
            MemoryStream ms = new MemoryStream();
            bmp.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
            ms.Flush();
            //将二进制数据存到byte数组中
            byte[] bmpBytes1 = ms.ToArray();
            bmp.Dispose();

            string bmpBytes = HttpUtility.UrlEncode("bmpBytes") + "=" + HttpServerUtility.UrlTokenEncode(bmpBytes1);

            string url = "http://192.168.0.28:9800/WebService1.asmx/Send_Image";
            string a = CallServiceByGet1(url, bmpBytes);

        }
        public static string CallServiceByGet1(string strURL,string a)
        {
            var result = string.Empty;
            //创建一个HTTP请求
            byte[] byt = Encoding.UTF8.GetBytes(a);
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(strURL);
            request.Method = "POST";
            request.ContentType = "application/x-www-form-urlencoded";
            request.ContentLength = byt.Length;
           
            request.UserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)";
            System.IO.Stream outputStream = request.GetRequestStream();
            outputStream.Write(byt, 0, byt.Length);
            outputStream.Close();

            HttpWebResponse response;
            Stream responseStream;
            StreamReader reader;
            string srcString;
            try
            {
                response = (HttpWebResponse)request.GetResponse();//获取http请求的响应对象
            }
            catch (WebException ex)
            {
                return ex.Message;
            }
            responseStream = response.GetResponseStream();
            reader = new System.IO.StreamReader(responseStream, Encoding.GetEncoding("UTF-8"));
            srcString = reader.ReadToEnd();
            result = srcString;   //返回值赋值
            reader.Close();

            return result;
        }