(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：

 1   protected void page_load(object sender, eventargs e)
 2         {
 3             bitmap bmp = new bitmap(system.drawing.image.fromfile("c:/users/tytd/desktop/测试样本/ch_dji_279.jpg"));
 4             memorystream ms = new memorystream();
 5             bmp.save(ms, system.drawing.imaging.imageformat.jpeg);
 6             ms.flush();
 7             //将二进制数据存到byte数组中
 8             byte[] bmpbytes1 = ms.toarray();
 9             bmp.dispose();
10 
11             string bmpbytes = httputility.urlencode("bmpbytes") + "=" + httpserverutility.urltokenencode(bmpbytes1);
12 
13             string url = "http://192.168.0.28:9800/webservice1.asmx/send_image";
14             string a = callservicebyget1(url, bmpbytes);
15 
16         }
17         public static string callservicebyget1(string strurl,string a)
18         {
19             var result = string.empty;
20             //创建一个http请求
21             byte[] byt = encoding.utf8.getbytes(a);
22             httpwebrequest request = (httpwebrequest)webrequest.create(strurl);
23             request.method = "post";
24             request.contenttype = "application/x-www-form-urlencoded";
25             request.contentlength = byt.length;
26            
27             request.useragent = "mozilla/4.0 (compatible; msie 6.0; windows nt 5.2; sv1; .net clr 1.1.4322; .net clr 2.0.50727)";
28             system.io.stream outputstream = request.getrequeststream();
29             outputstream.write(byt, 0, byt.length);
30             outputstream.close();
31 
32             httpwebresponse response;
33             stream responsestream;
34             streamreader reader;
35             string srcstring;
36             try
37             {
38                 response = (httpwebresponse)request.getresponse();//获取http请求的响应对象
39             }
40             catch (webexception ex)
41             {
42                 return ex.message;
43             }
44             responsestream = response.getresponsestream();
45             reader = new system.io.streamreader(responsestream, encoding.getencoding("utf-8"));
46             srcstring = reader.readtoend();
47             result = srcstring;   //返回值赋值
48             reader.close();
49 
50             return result;
51         }