在 Entity Framework 7 RC 1 和 ASP.NET MVC 6 中播种初始数据

问题描述

在 Entity Framework 7 中似乎还没有对种子数据的原生支持(https://github.com/aspnet/EntityFramework/issues/629).

It seems that in Entity Framework 7 there is no native support for seed data yet (https://github.com/aspnet/EntityFramework/issues/629).

微软提供的模板代码中没有DbMigrationsConfiguration类，没有Seed方法.

There is no DbMigrationsConfiguration class, no Seed method in the template code provided by Microsoft.

那么如何在使用 Entity Framework 7 RC 1 的 ASP.NET MVC 6 Web 应用程序中播种数据?

推荐答案

我为自己找到了一个临时解决方法.

I've found a temporary workaround for myself.

我们可以创建一个方法 SeedData 扩展 IApplicationBuilder 然后通过 GetService 方法获取我们的数据库上下文类的实例并将其用于播种数据.

We can create a method SeedData that extends the IApplicationBuilder then gets an instance of our database context class through GetService method and uses it for seeding the data.

这是我的扩展方法的样子:

Here is how my extension method looks like:

using Microsoft.AspNet.Builder;
using Microsoft.Extensions.DependencyInjection;

public static class DataSeeder
{
    // TODO: Move this code when seed data is implemented in EF 7

    /// <summary>
    /// This is a workaround for missing seed data functionality in EF 7.0-rc1
    /// More info: https://github.com/aspnet/EntityFramework/issues/629
    /// </summary>
    /// <param name="app">
    /// An instance that provides the mechanisms to get instance of the database context.
    /// </param>
    public static void SeedData(this IApplicationBuilder app)
    {
        var db = app.ApplicationServices.GetService<ApplicationDbContext>();

        // TODO: Add seed logic here

        db.SaveChanges();
    }
}

要使用它，请将 app.SeedData(); 行放在应用程序 Startup 类的 Configure 方法中(位于 web 项目中在名为 Startup.cs 的文件中).

To use it put app.SeedData(); line in the Configure method of the application Startup class (located in the web project in file called Startup.cs).

// This method gets called by the runtime.
// Use this method to configure the HTTP request pipeline.
public void Configure(
    IApplicationBuilder app,
    IHostingEnvironment env,
    ILoggerFactory loggerFactory)
{
    app.SeedData();

    // Other configuration code
}

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