[译]Use Dependency Injection In WebForms Application

怎么在已用的WebForm应用中使用DI

假设有一个电影网站，有个页面会列出最近热门的电影。这个项目中使用了仓储模式来获取数据。

public partial class Default : System.Web.UI.Page
{
    private IPopularMovie movieMgr = new MovieManager(new XmlMovieRepository());

    public async Task<SelectResult> movieList_GetData()
    {
        var movies = await movieMgr.GetPopularMoviesAsync();
        return new SelectResult(movies.Count(), movies);
    }
}

按照下面的4个步骤，可以在default.aspx.cs中使用DI。

1. 将项目指定为.NET Framework 4.7.2.

同时还需要修改web.config中的httpRuntime section的targetFramework。

2. 安装AspNet.WebFormsDependencyInjection.Unity NuGet package

3. 在Global.asax中注册类型

using System;
using Microsoft.AspNet.WebFormsDependencyInjection.Unity;
using PopularMovies.Bizlogic;
using PopularMovies.Repository;
using Unity;

namespace PopularMovies
{
    public class Global : System.Web.HttpApplication
    {
        protected void Application_Start(object sender, EventArgs e)
        {
            var container = this.AddUnity();

            container.RegisterType<IPopularMovie, MovieManager>();
            container.RegisterType<IMovieRepository, XmlMovieRepository>();
        }
    }
}

4. 修改 Default.aspx.cs

public partial class Default : System.Web.UI.Page
{
    private IPopularMovie movieMgr;
    public Default(IPopularMovie movieManager)
    {
        movieMgr = movieManager;
    }

    public async Task<SelectResult> movieList_GetData()
    {
        var movies = await movieMgr.GetPopularMoviesAsync();
        return new SelectResult(movies.Count(), movies);
    }
}

可以在哪些地方使用DI?

• Pages and controls
  • WebForms page
  • User control
  • Custom control
• IHttpHandler and IHttpHandlerFactory
• IHttpModule
• Providers
  • BuildProvider
  • ResourceProviderFactory
  • Health monitoring provider
  • Any ProviderBase based provider created by System.Web.Configuration.ProvidersHelper.InstantiateProvider. e.g. custom sessionstate provider