MEF的asp.net Hello World程序

1.了解MEF
2. 简单的demo
3. 代码下载

1. 了解MEF

mef是codeplex上的开源项目，地址：http://mef.codeplex.com/，工程目的： simplifying the design of extensible applications and components.

2. 简单demo

2.1 新建asp.net web application，添加 System.ComponentModel.Composition的应用。

2.2 添加一个web form页面aspnetMEFBasic.aspx，后台代码如下：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace MEF
{
    using System.ComponentModel.Composition;
    using System.ComponentModel.Composition.Hosting;

    public partial class aspnetMEFBasic : System.Web.UI.Page
    {
        [Import]
        Class1 c1;

        protected void Page_Load(object sender, EventArgs e)
        {
            //Step 1:
            //Find the assembly (.dll) that has the stuff
            // we need (i.e. [Export]ed stuff) and put it in our catalog
            DirectoryCatalog catalog =
                new DirectoryCatalog(System.IO.Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "bin"));

            //Step 2:
            //To do anything with the stuff in the catalog, we need to
            // put into a container (Which has methods to do the magic stuff)
            CompositionContainer container =
                new CompositionContainer(catalog);

            //Step 3:
            //Now lets do the magic bit - Wiring everything up
            container.ComposeParts(this);

            //Step4:
            //Lets see if it works
            div1.InnerText = c1.s1;
        }
    }

}

2.3 添加类Class1，代码如下：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

namespace MEF
{
    using System.ComponentModel.Composition;

    [Export]
    public class Class1
    {
        public string s1 = "Hello World";
    }
}