动态调用WebService

public static object InvokeWebService( string url,   string methodname, object [] args)

     其中，url是Web服务的地址，methodname是要调用服务方法名，args是要调用Web服务所需的参数，返回值就是web服务返回的结果了。

     要实现这样的功能，你需要这几个方面的技能：反射、CodeDom、编程使用C#编译器、WebService。在了解这些知识后，就可以容易的实现web服务的动态调用了：

         #region InvokeWebService
         // 动态调用web服务
         public static object InvokeWebService( string url, string methodname, object [] args)
         {
             return WebServiceHelper.InvokeWebService(url , null ,methodname ,args) ;
         }

         public static object InvokeWebService( string url,   string classname, string methodname, object [] args)
         {
             string @namespace = " EnterpriseServerBase.WebService.DynamicWebCalling " ;
             if ((classname == null ) || (classname == "" ))
             {
                 classname = WebServiceHelper.GetWsClassName(url) ;
             }

             try
             {
                 // 获取WSDL
                 WebClient wc                    = new WebClient();
                 Stream stream                   = wc.OpenRead(url + " ?WSDL " );
                 ServiceDescription sd           = ServiceDescription.Read(stream);
                 ServiceDescriptionImporter sdi = new ServiceDescriptionImporter();
                 sdi.AddServiceDescription(sd, "" , "" );
                 CodeNamespace cn                 = new CodeNamespace(@namespace);
                
                 // 生成客户端代理类代码
                 CodeCompileUnit ccu              = new CodeCompileUnit();
                 ccu.Namespaces.Add(cn);
                 sdi.Import(cn ,ccu);
                 CSharpCodeProvider csc           = new CSharpCodeProvider();
                 ICodeCompiler icc                = csc.CreateCompiler();
                
                 // 设定编译参数
                 CompilerParameters cplist        = new CompilerParameters();
                 cplist.GenerateExecutable        = false ;
                 cplist.GenerateInMemory          = true ;
                 cplist.ReferencedAssemblies.Add( " System.dll " );
                 cplist.ReferencedAssemblies.Add( " System.XML.dll " );
                 cplist.ReferencedAssemblies.Add( " System.Web.Services.dll " );
                 cplist.ReferencedAssemblies.Add( " System.Data.dll " );

                 // 编译代理类
                 CompilerResults cr = icc.CompileAssemblyFromDom(cplist, ccu);
                 if ( true == cr.Errors.HasErrors)
                 {
                     System.Text.StringBuilder sb = new System.Text.StringBuilder();
                     foreach (System.CodeDom.Compiler.CompilerError ce in cr.Errors)
                     {
                         sb.Append(ce.ToString());
                         sb.Append(System.Environment.NewLine);
                     }
                     throw new Exception(sb.ToString());
                 }

                 // 生成代理实例，并调用方法
                 System.Reflection.Assembly assembly = cr.CompiledAssembly;
                 Type t = assembly.GetType(@namespace + " . " + classname, true , true );
                 object obj = Activator.CreateInstance(t);
                 System.Reflection.MethodInfo mi = t.GetMethod(methodname);

                 return mi.Invoke(obj,args);
             }
             catch (Exception ex)
             {
                 throw new Exception(ex.InnerException.Message, new Exception(ex.InnerException.StackTrace));
             }
         }

         private static string GetWsClassName( string wsUrl)
         {
             string [] parts = wsUrl.Split( ' / ' ) ;
             string [] pps    = parts[parts.Length - 1 ].Split( ' . ' ) ;

             return pps[ 0 ] ;
         }
         #endregion

     上面的注释已经很好的说明了各代码段的功能，下面给个例子看看，这个例子是通过访问http://www.webservicex.net/globalweather.asmx 服务来获取各大城市的天气状况。

             string url = " http://www.webservicex.net/globalweather.asmx " ;
             string [] args = new string [ 2 ] ;
             args[ 0 ] = this .textBox_CityName.Text ;
             args[ 1 ] = " China " ;
             object result = WebServiceHelper.InvokeWebService(url , " GetWeather " ,args) ;
             this .label_Result.Text = result.ToString() ;