C# 通过HttpWebRequest在后台对WebService进行调用

using System;
using System.Web;
using System.Xml;
using System.Collections;
using System.Net;
using System.Text;
using System.IO;
using System.Xml.Serialization;
 
//By huangz 2008-3-19
 
 
/// <summary>
///  利用WebRequest/WebResponse进行WebService调用的类
 
/// </summary>
public class WebSvcCaller
{
    //<webServices>
    //  <protocols>
    //    <add name="HttpGet"/>
    //    <add name="HttpPost"/>
    //  </protocols>
    //</webServices>
 
    private static Hashtable _xmlNamespaces = new Hashtable();//缓存xmlNamespace，避免重复调用GetNamespace
 
    
    /// <summary>
    /// 需要WebService支持Post调用
    /// </summary>
    public static XmlDocument QueryPostWebService(String URL, String MethodName, Hashtable Pars)
    {
        HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(URL + "/" + MethodName);
        request.Method = "POST";
        request.ContentType = "application/x-www-form-urlencoded";
        SetWebRequest(request);
        byte[] data = EncodePars(Pars);
        WriteRequestData(request, data);
 
        return ReadXmlResponse(request.GetResponse());
    }
    
    /// <summary>
    /// 需要WebService支持Get调用
    /// </summary>
    public static XmlDocument QueryGetWebService(String URL, String MethodName, Hashtable Pars)
    {
        HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(URL + "/" + MethodName + "?" + ParsToString(Pars));
        request.Method = "GET";
        request.ContentType = "application/x-www-form-urlencoded";
        SetWebRequest(request);
        return ReadXmlResponse(request.GetResponse());
    }
 
 
    
    /// <summary>
    /// 通用WebService调用(Soap),参数Pars为String类型的参数名、参数值
    /// </summary>
    public static XmlDocument QuerySoapWebService(String URL, String MethodName, Hashtable Pars)
    {
        if (_xmlNamespaces.ContainsKey(URL))
        {
            return QuerySoapWebService(URL, MethodName, Pars, _xmlNamespaces[URL].ToString());
        }
        else
        {
            return QuerySoapWebService(URL, MethodName, Pars, GetNamespace(URL));
        }
    }
 
    private static XmlDocument QuerySoapWebService(String URL, String MethodName, Hashtable Pars, string XmlNs)
    {    
        _xmlNamespaces[URL] = XmlNs;//加入缓存，提高效率
        HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(URL);
        request.Method = "POST";
        request.ContentType = "text/xml; charset=utf-8";
        request.Headers.Add("SOAPAction", "\"" + XmlNs + (XmlNs.EndsWith("/") ? "" : "/") + MethodName + "\"");
        SetWebRequest(request);
        byte[] data = EncodeParsToSoap(Pars, XmlNs, MethodName);
        WriteRequestData(request, data);
        XmlDocument doc = new XmlDocument(), doc2 = new XmlDocument();
        doc = ReadXmlResponse(request.GetResponse());
 
        XmlNamespaceManager mgr = new XmlNamespaceManager(doc.NameTable);
        mgr.AddNamespace("soap", "http://schemas.xmlsoap.org/soap/envelope/");
        String RetXml = doc.SelectSingleNode("//soap:Body/*/*", mgr).InnerXml;
        doc2.LoadXml("<root>" + RetXml + "</root>");
        AddDelaration(doc2);
        return doc2;
    }
    private static string GetNamespace(String URL)
    {
        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(URL + "?WSDL");
        SetWebRequest(request);
        WebResponse response = request.GetResponse();
        StreamReader sr = new StreamReader(response.GetResponseStream(), Encoding.UTF8);
        XmlDocument doc = new XmlDocument();
        doc.LoadXml(sr.ReadToEnd());
        sr.Close();
        return doc.SelectSingleNode("//@targetNamespace").Value;
    }
    private static byte[] EncodeParsToSoap(Hashtable Pars, String XmlNs, String MethodName)
    {
        XmlDocument doc = new XmlDocument();
        doc.LoadXml("<soap:Envelope xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xmlns:xsd=\"http://www.w3.org/2001/XMLSchema\" xmlns:soap=\"http://schemas.xmlsoap.org/soap/envelope/\"></soap:Envelope>");
        AddDelaration(doc);
        XmlElement soapBody = doc.createElement_x_x("soap", "Body", "http://schemas.xmlsoap.org/soap/envelope/");
        XmlElement soapMethod = doc.createElement_x_x(MethodName);
        soapMethod.SetAttribute("xmlns", XmlNs);
        foreach (string k in Pars.Keys)
        {
            XmlElement soapPar = doc.createElement_x_x(k);
            soapPar.InnerXml = ObjectToSoapXml(Pars[k]);
            soapMethod.appendChild_xss(soapPar);
        }
        soapBody.appendChild_xss(soapMethod);
        doc.DocumentElement.appendChild_xss(soapBody);
        return Encoding.UTF8.GetBytes(doc.OuterXml);
    }
    private static string ObjectToSoapXml(object o)
    {
        XmlSerializer mySerializer = new XmlSerializer(o.GetType());
        MemoryStream ms = new MemoryStream();
        mySerializer.Serialize(ms, o);
        XmlDocument doc = new XmlDocument();
        doc.LoadXml(Encoding.UTF8.GetString(ms.ToArray()));
        if (doc.DocumentElement != null)
        {
            return doc.DocumentElement.InnerXml;
        }
        else
        {
            return o.ToString();
        }
    }
    private static void SetWebRequest(HttpWebRequest request)
    {
        request.Credentials = CredentialCache.DefaultCredentials;
        request.Timeout = 10000;
    }
 
    private static void WriteRequestData(HttpWebRequest request, byte[] data)
    {
        request.ContentLength = data.Length;
        Stream writer = request.GetRequestStream();
        writer.Write(data, 0, data.Length);
        writer.Close();
    }
 
    private static byte[] EncodePars(Hashtable Pars)
    {
        return Encoding.UTF8.GetBytes(ParsToString(Pars));
    }
 
    private static String ParsToString(Hashtable Pars)
    {
        StringBuilder sb = new StringBuilder();
        foreach (string k in Pars.Keys)
        {
            if (sb.Length > 0)
            {
                sb.Append("&");
            }
            //sb.Append(HttpUtility.UrlEncode(k) + "=" + HttpUtility.UrlEncode(Pars[k].ToString()));
        }
        return sb.ToString();
    }
 
    private static XmlDocument ReadXmlResponse(WebResponse response)
    {
        StreamReader sr = new StreamReader(response.GetResponseStream(), Encoding.UTF8);
        String retXml = sr.ReadToEnd();
        sr.Close();
        XmlDocument doc = new XmlDocument();
        doc.LoadXml(retXml);
        return doc;
    }
 
    private static void AddDelaration(XmlDocument doc)
    {
        XmlDeclaration decl = doc.CreateXmlDeclaration("1.0", "utf-8", null);
        doc.InsertBefore(decl, doc.DocumentElement);
    }
}
 
  
 
  
 
调用示例：
 
Hashtable ht = new Hashtable();
ht.Add("str", "test");
ht.Add("b", "true");
XmlDocument xx = WebSvcCaller.QuerySoapWebService("http://localhost:81/service.asmx", "HelloWorld", ht);
MessageBox.Show(xx.OuterXml);