asp.net调用web service不通过添加web引用的方式怎么调用

//动态调用web服务
        public static object InvokeWebSer(string url,string @namespace, string classname, string methodname, object[] args)
        {
                System.Net.WebClient wc = new System.Net.WebClient();
                string URL=string.Empty;
                if ((url.Substring(url.Length - 5, 5) != null) && ((url.Substring(url.Length - 5, 5).ToLower() != "?wsdl")))
                    URL = url + "?WSDL";
                else
                    URL = url;
                System.IO.Stream stream = wc.OpenRead(URL);
                System.Web.Services.Description.ServiceDescription sd = System.Web.Services.Description.ServiceDescription.Read(stream);
                System.Web.Services.Description.ServiceDescriptionImporter sdi = new System.Web.Services.Description.ServiceDescriptionImporter();
                sdi.AddServiceDescription(sd, "", "");
                System.CodeDom.CodeNamespace cn = new System.CodeDom.CodeNamespace(@namespace);
                System.CodeDom.CodeCompileUnit ccu = new System.CodeDom.CodeCompileUnit();
                ccu.Namespaces.Add(cn);
                sdi.Import(cn, ccu);
 
                Microsoft.CSharp.CSharpCodeProvider csc = new Microsoft.CSharp.CSharpCodeProvider();
 
                System.CodeDom.Compiler.CompilerParameters cplist = new System.CodeDom.Compiler.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");
 
                System.CodeDom.Compiler.CompilerResults cr = csc.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());
                }
                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);
        }    

object obj = InvokeWebservice("http://localhost/GSP_WorkflowWebservice/common.asmx",
                              "YouNamespace",  // 欲调用的WebService的命名空间
                              "ServiceName",   // 欲调用的WebService的类名（不包括命名空间前缀）
                              "MethodName",    // 欲调用的WebService的方法名
                              new object[]{"1"}); //传入参数