WebService的调用

发布时间：2020-12-17 02:12:03 所属栏目：安全来源：网络整理

导读：C#如何动态调用Web服务 2009-06-26 14:49 ???? http://blog.csdn.net/turejackon/archive/2008/12/30/3658236.aspx ???? 我们在开发C# WinForm时，有时会调用Web服务，服务是本地的当前好办，只要在Project中的Web References中引入就可以在代码中直接创建一

C#如何动态调用Web服务

2009-06-26 14:49

???? http://blog.csdn.net/turejackon/archive/2008/12/30/3658236.aspx

???? 我们在开发C# WinForm时，有时会调用Web服务，服务是本地的当前好办，只要在Project中的Web References中引入就可以在代码中直接创建一个Web服务对象来引用，其实其原理是C#帮你自动创建客户端代理类的方式调用 WebService，但如果调用的服务是动态的，比如说在几个IIS中都有相同的一个服务，在运行时输入具体的IP才确定调用哪个服务，那要怎么样实现呢。

方法一： 手动的添加一个Web引用，然后修改下本地的代理类。最后实现Web Service的URI部署到配置文件里。具体做法如下：

以下代码是显示如何配置动态的Web Service，以服务单元C（类名为Web_SVSGC）为例：

(1)首先在Web引用中的本地代理类中添加一个构造函数，这个构造函数是以Web Service的URL为参数的重载方法。
复制保存Namespace Web_SVSGC
??? '<remarks/>
??? <System.Diagnostics.DebuggerStepThroughAttribute(),_???? System.ComponentModel.DesignerCategoryAttribute("code"),_???? System.Web.Services.WebServiceBindingAttribute(Name:="SVSGCSoap",[Namespace]:="http://tempuri.org/QYJSERVICE/SVSGC"),_???? System.Xml.Serialization.XmlIncludeAttribute(GetType(Attribute))> _
??? Public Class SVSGC
??????? Inherits System.Web.Services.Protocols.SoapHttpClientProtocol
??? '<remarks/>
??????? Public Sub New()
??????????? MyBase.New
??????????? Me.Url = "http://localhost/QYJSERVICE/WEBSERVICE/SERVICE/SVSGC.asmx"
??????? End Sub

??????? '添加一个带参数的构造函数。
??????? Public Sub New(ByVal strUrl As String)
??????????? MyBase.New()
??????????? Me.Url = strUrl
??????? End Sub

(2)将Web Service的url配置在调用Web Service的应用程序的配置文件中。（其中的value可以随时修改。）

复制保存<configuration>
??? <appSettings>
????????????? <add key="SVSGA_URL" value="http://192.168.108.188/ QDN/SERVICE/SVSGA.asmx" QDN/SERVICE/SVSGA.asmx" />
??? </appSettings>
</configuration><configuration>
??? <appSettings>
????????????? <add key="SVSGA_URL" value="http://192.168.108.188/ QDN/SERVICE/SVSGA.asmx" QDN/SERVICE/SVSGA.asmx" />
??? </appSettings>
</configuration>

(3)调用时，根据配置文件的Url动态的生成Web Service。
复制保存'要调用的Web Service的URL
??????? Dim strWebSvsUrl As String
??????? '声明一个要调用的Web Service
??????? Dim objSVSGC As WebSvs_GC. SVSGC
??????? '调用Web Service的远程方法的返回值
??????? Dim strReturnValue As String
??????? Try
??????????? '从配置文件中取得Web Service的URL
??????????? strWebSvsUrl = _
??????????? System.Configuration.ConfigurationSettings.AppSettings("SVSGC_URL")
??????????? '生成一个Web Service实例
??????????? objSVSGC = New WebSvs_GC.SVSGC (strWebSvsUrl)
??????????? '调用这个Web Service里的远程方法
??????????? strReturnValue = objSVSGC.HelloWorld()
??????? Catch ex As Exception
??????? End Try

方法二：完全动态处理,传入服务服务网址,方法名和参数即可.

 
using System; 

using System.Net; 

using System.IO; 

using System.CodeDom; 

using Microsoft.CSharp; 

using System.CodeDom.Compiler; 

using System.Web.Services.Description; 

using System.Web.Services.Protocols; 

namespace HB.Common 

{ 

????/* 调用方式 

????? *??? string url = "http://www.webservicex.net/globalweather.asmx" ; 

????? *??? string[] args = new string[2] ; 

????? *??? args[0] = "Hangzhou"; 

????? *??? args[1] = "China" ; 

????? *??? object result = WebServiceHelper.InvokeWebService(url,"GetWeather",args) ; 

????? *??? Response.Write(result.ToString()); 

????? */ 

????public class WebServiceHelper 
???? { 
???????? #region InvokeWebService 

????????/// <summary> 

????????/// 动态调用web服务 

????????/// </summary> 

????????/// <param name="url">WSDL服务地址</param> 

????????/// <param name="methodname">方法名</param> 

????????/// <param name="args">参数</param> 

????????/// <returns></returns> 

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

???????? { 

????????????return WebServiceHelper.InvokeWebService(url,null,methodname,args); 

???????? } 

????????/// <summary> 

????????/// 动态调用web服务 

????????/// </summary> 

????????/// <param name="url">WSDL服务地址</param> 

????????/// <param name="classname">类名</param> 

????????/// <param name="methodname">方法名</param> 

????????/// <param name="args">参数</param> 

????????/// <returns></returns> 

????????public static object InvokeWebService(string url,string classname,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 icc = new CSharpCodeProvider(); 

????????????????//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); 

????????????????/* 

???????????????? PropertyInfo propertyInfo = type.GetProperty(propertyname); 

???????????????? return propertyInfo.GetValue(obj,null); 

???????????????? */ 

???????????? } 

????????????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 

???? } 

}

返回时如果不是字符串,即强制转换,如返回是DataSet,则

 
string url = "http://www.webservicex.net/globalweather.asmx" ; 

string[] args = new string[2] ; 

args[0] = "Hangzhou"; 

args[1] = "China" ; 

object result = WebServiceHelper.InvokeWebService(url,"GetWeather",args) ; 

DataSet DSRe=(DataSet)result;

方法三：URL Behavior 属性

如果知道服务的方法和参数,只是调用的URL网址会随时变化,那么可以手工创建一个服务,添加上对应的的方法和传入参数,然后引入到项目中,就可以直接开发,在创建服务的实例化时,才修改对应的URL即可.

例如服务中有个方法叫GetTax,那么就可以这样改:

GetTax.GetTax GetTax1 = new GetTax.GetTax();
GetTax1.Url = "http://" + WebIp1 + "/

（编辑：李大同）

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