如何在startup.cs(ASP.net core 1.1)的ConfigureServices方法中正确注入DbContext实例?

问题描述

我已经为我的ASP.NET核心Web应用程序实现了 EntityFrameworkFileProvider ，我希望 ViewDbContext 实例由ASP.NET核心DI框架在构造函数中注入:

I have implemented the EntityFrameworkFileProvider for my ASP.NET core web application, I want the ViewDbContext instance to be injected by ASP.NET core DI framework in the constructor:

( ViewDbContext 是 dbContext )

public class EntityFrameworkFileProvider : IFileProvider
{
    private ViewDbContext _context;

    public EntityFrameworkFileProvider(ViewDbContext context)
    { 
       /* should be injected by asp.net core DI */
        _context = context;
    }
    public IDirectoryContents GetDirectoryContents(string subpath)
    {
        .....
    }

    public IFileInfo GetFileInfo(string subpath)
    {
        var result = new DatabaseFileInfo(_context, subpath);
        return result.Exists ? result as IFileInfo : new NotFoundFileInfo(subpath);
    }

    public IChangeToken Watch(string filter)
    {
        return new DatabaseChangeToken(_context, filter);
    }
}

现在，我在startup.cs中将 EntityFrameworkFileProvider 添加到 RazorViewEngineOption 如何使 ViewDbContext 实例可以由DI框架在startup.cs的 ConfigureServices 方法中自动注入?我应该如何正确调用 EntityFrameworkFileProvider 构造函数?

Now I add the EntityFrameworkFileProvider to RazorViewEngineOption in startup.csHow to make the ViewDbContext instance to be automatically injected by DI framework in the ConfigureServices method of startup.cs? how should i call the EntityFrameworkFileProvider constructor correctly?

在Startup.cs

In Startup.cs

public void ConfigureServices(IServiceCollection services)
{
      /* Add  EntityFrameworkFileProvider to Razor engine */
      services.Configure<RazorViewEngineOptions>(opts =>
      {
          opts.FileProviders.Add(new EntityFrameworkFileProvider(null?));
      });

      services.AddMvc();
}

推荐答案

我认为我已经找到了解决方案！有什么主意吗?

i think i have found the solution! any idea?

public void ConfigureServices(IServiceCollection services)
{
     services.AddDbContext<ViewDbContext>(options => 
       options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));
    ...
     /* Add  EntityFrameworkFileProvider to Razor engine */       
     var context = services.BuildServiceProvider()
                       .GetService<ViewDbContext>();

     services.Configure<RazorViewEngineOptions>(opts =>
     {
         opts.FileProviders.Add(new EntityFrameworkFileProvider(context));
     });

     services.AddMvc();
}

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