一直以来，我都为动态调用WebService方法而烦恼。在.Net环境 下，最常用的方法就是采用代理类来调用WebService，可以通过改变代理类的Url属性来实现动态调用，但当xmlns改变时就会出错，似乎要重新 绑定Webservice并重新编译后才能再次运行。我还试过网上的一种动态编译并动态调用WebService的方式，这种方法效率低，而且需要有较高 的权限，否则编译失败。我曾在Sql Server 2005的CLR存储过程中用此方法调用WebService时，浪费了大半天时间，无论怎么试它就是不能成功编译。于是我便不断思考其他的方法，今天晚 上终于写了一个类用于动态调用WebService，只需传入WebService地址、需调用的方法及其参数，就可以随时动态调用了。现分享给大家，代 码如下：

using System;
using System.Web;
using System.Xml;
using System.Collections;
using System.Net;
using System.Text;
using System.IO;
/**////

/// 利用WebRequest/WebResponse进行WebService调用的类,By 同济黄正
///

public class WebSvcCaller
...{
    //
    //
    //   
    //   
    //
    //
    private static Hashtable _xmlNamespaces = new Hashtable();//缓存xmlNamespace，避免重复调用GetNamespace
    /**////

    /// 需要WebService支持Post调用
    ///

    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());
    }
    /**////

    /// 需要WebService支持Get调用
    ///

    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());
    }

    /**////

    /// 通用WebService调用(Soap),参数Pars为String类型的参数名、参数值
    ///

    public static XmlDocument QuerySoapWebService(String URL , String MethodName , Hashtable Pars)
    ...{
        //By 同济黄正 http://hz932.ys168.com 2008-3-19
        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("" + RetXml + "");
        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());
        return doc.SelectSingleNode("//@targetNamespace").Value;
    }
    private static byte[] EncodeParsToSoap(Hashtable Pars , String XmlNs , String MethodName)
    ...{
        XmlDocument doc = new XmlDocument();
        doc.LoadXml("http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap="0