ASP.NET MVC中将控制器分离到类库的实现

// 源文件头信息：
// <copyright file="ControllersFactory.cs">
// Copyright(c)2014-2034 Kencery.All rights reserved.
// 创建人：韩迎龙(kencery)
// 创建时间：2015-6-18
// </copyright>

using System;
using System.Reflection;
using System.Web.Mvc;
using System.Web.Routing;
using System.Web.SessionState;

namespace BookSystem_Controllers
{
  /// <summary>
  /// 重写注册控制器的方法，使之能够将控制器管分离到其它类库中实现
  /// <auther>
  ///   <name>kencery</name>
  ///   <date>2015-6-18</date>
  /// </auther>
  /// </summary>
  /// 说明：IControllerFactory接口含有三个需要实现的方法：CreateController，GetControllerSessionBehavior，ReleaseController
  /// 使用：在MVC App_Start文件夹中的RouteConfig中的方法RegisterRoutes中的第一行中写入下面注册语句,Global.asax中也可注册，放到注册路由之前即可
  /// ControllerBuilder.Current.SetControllerFactory(new ControllersFactory("BookSystem_Controllers")); //BookSystem_Controllers为控制器的类库
  public class ControllersFactory : IControllerFactory
  {
    private readonly string _assemblyName;
    private readonly string _controlerDefaultNameSpage;
    private Assembly _controllerAssembly;

    /// <summary>
    /// 获取控制器所在的程序集名称
    /// </summary>
    public string AssemblyName
    {
      get { return _assemblyName; }
    }

    /// <summary>
    /// 获取控制器的默认命名空间
    /// </summary>
    public string ControlerDefaultNameSpage
    {
      get { return _controlerDefaultNameSpage; }
    }

    /// <summary>
    /// 获取控制器所在的程序集的Assembly实例
    /// </summary>
    public Assembly ControllerAssembly
    {
      get
      {
        return _controllerAssembly ?? (_controllerAssembly = Assembly.Load(AssemblyName)); //加载控制器信息
      }
    }

    /// <summary>
    /// 构造函数实例化
    /// </summary>
    /// <param name="assemblyName"></param>
    public ControllersFactory(string assemblyName)
    {
      _assemblyName = assemblyName;
    }

    /// <summary>
    /// 构造函数实例化
    /// </summary>
    /// <param name="assemblyName"></param>
    /// <param name="controlerDefaultNameSpage"></param>
    public ControllersFactory(string assemblyName, string controlerDefaultNameSpage)
    {
      _assemblyName = assemblyName;
      _controlerDefaultNameSpage = controlerDefaultNameSpage;
    }

    /// <summary>
    /// 获取控制器类的全名
    /// </summary>
    /// <param name="controllerName">控制器名称</param>
    public string GetControllerFullName(string controllerName)
    {
      return string.Format("{0}.{1}Controller",
        string.IsNullOrEmpty(ControlerDefaultNameSpage) ? AssemblyName : ControlerDefaultNameSpage,
        controllerName);
    }

    /// <summary>
    /// 获取控制器实例对象，根据controllerName生成一个没有请求上下文对象的空的控制器，在为此控制器制定ControllerContext对象，然后返回控制器实例
    /// </summary>
    /// <param name="requestContext"></param>
    /// <param name="controllerName"></param>
    public IController CreateController(RequestContext requestContext, string controllerName)
    {
      var controller = ControllerAssembly.CreateInstance(GetControllerFullName(controllerName)) as Controller;
      if (controller == null)
        return null;
      if (controller.ControllerContext == null)
      {
        controller.ControllerContext = new ControllerContext(requestContext, controller);
      }
      else
      {
        controller.ControllerContext.RequestContext = requestContext;
      }
      return controller;
    }

    /// <summary>
    /// 返回请求的会话状态的支持类型
    /// </summary>
    /// <param name="requestContext"></param>
    /// <param name="controllerName"></param>
    public SessionStateBehavior GetControllerSessionBehavior(RequestContext requestContext, string controllerName)
    {
      var controllerType = ControllerAssembly.GetType(GetControllerFullName(controllerName), true, true);
      var sessionStateAttr =
        Attribute.GetCustomAttribute(controllerType, typeof (SessionStateAttribute), false) as
          SessionStateAttribute;
      return sessionStateAttr == null ? SessionStateBehavior.Default : sessionStateAttr.Behavior;
    }

    /// <summary>
    /// 释放资源
    /// </summary>
    /// <param name="controller"></param>
    public void ReleaseController(IController controller)
    {
      var idDisposable = controller as IDisposable;
      if (idDisposable != null)
      {
        idDisposable.Dispose();
      }
    }
  }
}

//系统默认路由
    routes.MapRoute(
      name: "Default",
      url: "{controller}/{action}/{id}",
      defaults: new {controller = "Login", action = "Index", id = UrlParameter.Optional},
      namespaces: new string[] {"BookSystem_Controllers"}
);