微软企业库5.0学习笔记（10）ASP.NET模块依赖注入

    您可以使用HTTP模块，一个到ASP.NET HttpApplicationState类的扩展，在Global.asax编写代码强制ASP.NET在每一个页面请求时自动注入依赖的对象，就像在ASP.NET Web窗体应用程序中讨论的一样.
    下列方法显示了一个合适的方法能够获取PreRequestHandlerExecute事件将它自己注入到ASP.NET的执行流水线，在每个页面请求中通过容器的BuildUp方法运行Http模块，并获取OnPageInitComplete事件。当OnPageInitComplete执行时模块代码按照所有的控件树运行，并通过容器的BuildUp方法处理每个控件。
    BuildUp方法获取已经存在的对象实例，处理并填充类的依赖，返回实例。如果没有依赖则返回最初的实例。
     using System;
using System.Collections.Generic;
using System.Web;
using System.Web.UI;
using Microsoft.Practices.Unity;
namespace Unity.Web
{
public class UnityHttpModule : IHttpModule
{
public void Init(HttpApplication context)
{
context.PreRequestHandlerExecute += OnPreRequestHandlerExecute;
}
public void Dispose() { }
private void OnPreRequestHandlerExecute(object sender, EventArgs e)
{
IHttpHandler currentHandler = HttpContext.Current.Handler;
HttpContext.Current.Application.GetContainer().BuildUp(
currentHandler.GetType(), currentHandler);
// User Controls are ready to be built up after page initialization is complete
var currentPage = HttpContext.Current.Handler as Page;
if (currentPage != null)
{
currentPage.InitComplete += OnPageInitComplete;
}
}
// Build up each control in the page's control tree
private void OnPageInitComplete(object sender, EventArgs e)
{
var currentPage = (Page)sender;
IUnityContainer container = HttpContext.Current.Application.GetContainer();
foreach (Control c in GetControlTree(currentPage))
{
container.BuildUp(c.GetType(), c);
}
context.PreRequestHandlerExecute -= OnPreRequestHandlerExecute;
}
// Ge