Httwebrequest调用webservice

webservice的webconfig配置，不配置后面会报远程服务器返回错误: (500) 内部服务器错误，跨域错误。

  <system.web>
    <compilation debug="true" targetFramework="4.0" />
    <webServices>
      <protocols>
        <add name= "HttpPost"/>
        <add name= "HttpGet"/>
      </protocols>
    </webServices>
  </system.web>

<configuration>
 <system.webServer>  
    <httpProtocol>   
    <customHeaders>   
      <add name="Access-Control-Allow-Methods" value="OPTIONS,POST,GET"/>   
      <add name="Access-Control-Allow-Headers" value="x-requested-with,content-type"/>   
      <add name="Access-Control-Allow-Origin" value="*" />   
    </customHeaders>   
  </httpProtocol>   
  <modules>  
    <add name="MyHttpModule" type="WebServiceDemo.MyHttpModule"/>  
  </modules>
  </system.webServer>  
</configuration>

如果报错：

未能加载类型“WebServiceDemo.MyHttpModule”。去掉

 <modules>  
    <add name="MyHttpModule" type="WebServiceDemo.MyHttpModule"/>  
  </modules>

webserviceDemo.asmx

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Services;

namespace News.webservice
{
    /// <summary>
    /// WebServiceDemo 的摘要说明
    /// </summary>
    [WebService(Namespace = "http://tempuri.org/")]
    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
    [System.ComponentModel.ToolboxItem(false)]
    // 若要允许使用 ASP.NET AJAX 从脚本中调用此 Web 服务，请取消注释以下行。 
    [System.Web.Script.Services.ScriptService]
    public class WebServiceDemo : System.Web.Services.WebService
    {

        [WebMethod]
        public string HelloWorld(string name,string name1)
        {
            return name+name1;
        }
    }
}

前台调用

  $.ajax({
		            type: "POST", //访问WebService使用Post方式请求
		            contentType: "application/json;charset=utf-8", //WebService 会返回Json类型

		            url: "http://localhost:1071/webservice/WebServiceDemo.asmx/HelloWorld",

		            data: "{name:"" + 123 + ""}", //企业id参数
		            dataType: 'json',
		            beforeSend: function (x) { x.setRequestHeader("Content-Type", "application/json; charset=utf-8"); },
		            error: function (x, e) { alert('fail'); },
		            success: function (result) { //回调函数，result，返回值

		                alert(JSON.stringify(result));
		            }
		        });

　　

后台调用  转自：http://www.cnblogs.com/ghelement/p/5286630.html 

  static void Main(string[] args)
        {

          string a=  GetStringByUrl("http://localhost:1071/webservice/WebServiceDemo.asmx/HelloWorld?name=youchim");
       
         
          string b= RequestWebService("http://localhost:1071/webservice/WebServiceDemo.asmx/HelloWorld","name=朱一届&name1=youchim");
        
          }
   //get
    public static string GetStringByUrl(string strUrl)
        {
            HttpWebRequest req = (HttpWebRequest)WebRequest.Create(strUrl);
            req.UserAgent = "MSIE6.0";
            req.Method = "GET";
            //http://www.cnblogs.com/cresuccess/archive/2009/12/09/1619977.html
            HttpWebResponse res;
            try
            {
                res = (HttpWebResponse)req.GetResponse();
            }
            catch (WebException ex)
            {
                res = (HttpWebResponse)ex.Response;
            }
          
         
            StreamReader sr = new StreamReader(res.GetResponseStream(), Encoding.GetEncoding("UTF-8"));
            string  strHtml = sr.ReadToEnd();
            sr.Close();
            res.Close();
            return strHtml;
           
        }
        //post方法

        public static string RequestWebService(string strUrl, string strPostData)
        {
            try
            {
                //构造请求
                HttpWebRequest hwrRequest = (HttpWebRequest)WebRequest.Create(strUrl);
                hwrRequest.Method = "POST";
                hwrRequest.Accept = "image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, application/x-shockwave-flash, */*";
                hwrRequest.Headers.Add("Accept-Encoding", "gzip, deflate");
                hwrRequest.Headers.Add("Accept-Language", "zh-cn");
                hwrRequest.Headers.Add("Cache-Control", "gzip, deflate");
                hwrRequest.Headers.Add("KeepAlive", "TRUE");
                hwrRequest.Headers.Add("ContentLength", strPostData.Length.ToString());
                hwrRequest.ContentType = "application/x-www-form-urlencoded";
                hwrRequest.Referer = strUrl;
                hwrRequest.Headers.Add("UA-CPU", "x86");
                hwrRequest.UserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)";
                hwrRequest.Timeout = 30000;
                hwrRequest.ServicePoint.Expect100Continue = false;

                //发送请求
                byte[] bytPostData = Encoding.UTF8.GetBytes(strPostData);
                Stream strStream = hwrRequest.GetRequestStream();
                strStream.Write(bytPostData, 0, bytPostData.Length);
                strStream.Close();

                //就收应答
                HttpWebResponse hwrResponse = (HttpWebResponse)hwrRequest.GetResponse();
                Stream strStream1 = null;
                if (hwrResponse.ContentEncoding == "gzip")
                {
                    System.IO.Compression.GZipStream gzsStream = new System.IO.Compression.GZipStream(hwrResponse.GetResponseStream(), System.IO.Compression.CompressionMode.Decompress);
                    strStream1 = gzsStream;
                }
                else
                {
                    strStream1 = hwrResponse.GetResponseStream();
                }

                string strResult = new StreamReader(strStream1, System.Text.Encoding.UTF8).ReadToEnd();
                hwrResponse.Close();

                return strResult;
            }
            catch (Exception excResult)
            {
                return "";
            }
        }