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微软企业库5.0学习笔记（10）ASP.NET模块依赖注入

2024-07-14 04:32:18   219人阅读

 

本文出自：http://blog.csdn.net/sfbirp/article/details/5621272

 

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;      }        // Get the controls in the page‘s control tree excluding the page itself      private IEnumerable<Control> GetControlTree(Control root)      {        foreach (Control child in root.Controls)        {          yield return child;          foreach (Control c in GetControlTree(child))          {            yield return c;          }        }      }    }  }

    下面显示了一个应用程序状态的实现，并暴露一个静态的 GetContainer方法，这个方法能够在

Application状态中创建一个新的统一容器，如果不存在的话，或者返回一个存在的实例的引用。

 

using System.Web;  using Microsoft.Practices.Unity;    namespace Unity.Web  {    public static class HttpApplicationStateExtensions    {      private const string GlobalContainerKey = "EntLibContainer";        public static IUnityContainer GetContainer(this HttpApplicationState appState)      {        appState.Lock();        try        {          var myContainer = appState[GlobalContainerKey] as IUnityContainer;          if (myContainer == null)          {            myContainer = new UnityContainer();            appState[GlobalContainerKey] = myContainer;          }          return myContainer;        }        finally        {            appState.UnLock();        }      }    }  }


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