微軟企業庫5.0學習筆記（10）ASP.NET模組依賴注入

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

 

您可以使用HTTP模組，一個到ASP.NET HttpApplicationState類的擴充，在Global.asax編寫代碼強制ASP.NET在每一個頁面請求時自動注入依賴的對象，就像在ASP.NET Web表單應用程式中討論的一樣.

    下列方法顯示了一個合適的方法能夠擷取PreRequestHandlerExecute事件將它自己注入到ASP.NET的執行流水線，在每個頁面請求中通過容器的BuildUp方法運行Http模組，並擷取OnPageInitComplete事件。當OnPageInitComplete執行時模組代碼按照所有的控制項樹運行，並通過容器的BuildUp方法處理每個控制項。

    BuildUp方法擷取已經存在的對象執行個體，處理並填充類的依賴，返回執行個體。如果沒有依賴則返回最初的執行個體。

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;          }        }      }    }  }  

    下面顯示了一個應用程式狀態的實現，並暴露一個靜態 GetContainer方法，這個方法能夠在

Application狀態中建立一個新的統一容器，如果不存在的話，或者返回一個存在的執行個體的引用。

 

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();        }      }    }  }