.NET 下动态设置 WebService 引用

    做需要部署 WebService 的项目时，要根据部署环境环境设置 WebService 引用。VS(2008)下可以引用 WebService 并且引用地址也设置在app.config(winform)中，但引用后生成了一堆配置文件，并且配置文件中含有引用地址，给人硬编码的错觉。如果手动引用，稍微配置可达到同样的效果。即使用 WSDL.exe 工具生成WebService的代理，本地调用即可。
有如下 WebService ：

using System;
using System.Web;
using System.Web.Services;
using System.Web.Services.Protocols;

[WebService(Namespace = " http://tempuri.org/ " )]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
public class Service : System.Web.Services.WebService
{
     public Service () {

         // Uncomment the following line if using designed components
         // InitializeComponent();
    }

    [WebMethod]
     public int Sum( int a, int b)
    {
         int c = a + b;

         return c;
    }
    
}

 WSDL.exe 命令行为：wsdl /n:namespace1 /out:c:\service1.cs http://localhost/WebServiceHTTP/Service.asmx?WSDL
生成的代理文件内容为：

// ------------------------------------------------------------------------------
// <auto-generated>
//      This code was generated by a tool.
//      Runtime Version:2.0.50727.1433
//
//      Changes to this file may cause incorrect behavior and will be lost if
//      the code is regenerated.
// </auto-generated>
// ------------------------------------------------------------------------------

//
// This source code was auto-generated by wsdl, Version=2.0.50727.1432.
//
namespace namespace1 {
     using System.Diagnostics;
     using System.Web.Services;
     using System.ComponentModel;
     using System.Web.Services.Protocols;
     using System;
     using System.Xml.Serialization;
    
    
     /// <remarks/>
    [System.CodeDom.Compiler.GeneratedCodeAttribute( " wsdl " , " 2.0.50727.1432 " )]
    [System.Diagnostics.DebuggerStepThroughAttribute()]
    [System.ComponentModel.DesignerCategoryAttribute( " code " )]
    [System.Web.Services.WebServiceBindingAttribute(Name = " ServiceSoap " , Namespace = " http://tempuri.org/ " )]
     public partial class Service : System.Web.Services.Protocols.SoapHttpClientProtocol {
        
         private System.Threading.SendOrPostCallback SumOperationCompleted;
        
         /// <remarks/>
         public Service() {
             this .Url = " http://localhost/WebServiceHTTP/Service.asmx " ;
        }
        
         /// <remarks/>
         public event SumCompletedEventHandler SumCompleted;
        
         /// <remarks/>
        [System.Web.Services.Protocols.SoapDocumentMethodAttribute( " http://tempuri.org/Sum " , RequestNamespace = " http://tempuri.org/ " , ResponseNamespace = " http://tempuri.org/ " , Use = System.Web.Services.Description.SoapBindingUse.Literal, ParameterStyle = System.Web.Services.Protocols.SoapParameterStyle.Wrapped)]
         public int Sum( int a, int b) {
             object [] results = this .Invoke( " Sum " , new object [] {
                        a,
                        b});
             return (( int )(results[ 0 ]));
        } 
         //还有很多...

然后把构造方法中的 this .Url = " http://localhost/WebServiceHTTP/Service.asmx " ; 在app.config中配置即可。

this.Url = ConfigurationManager.AppSettings.Get("service1"); 

app.config 中的内容为：

<? xml version="1.0" encoding="utf-8" ?>
< configuration >
   < appSettings >
     < add key ="service1" value ="http://localhost/WebServiceHTTP/Service.asmx" />    </ appSettings >
</ configuration >

这样做有个缺点，就是每次修改 WebService后都要重新生成一遍，设置URL。可以调试的时候直接用VS引用，完成后手工引用即可。也可写一个批处理生成代理。也可以再写一个代理，派生自WSDL.exe生成的代理，把URL以参数的形式传到WSDL.exe生成的代理。
WSDL.exe的使用方法可参考：http://msdn2.microsoft.com/en-us/library/7h3ystb6(VS.80).aspx