沒有配置數據庫提供程序用於此DbContext獲取方法在Asp.netCore

Question

我創建了一個由Asp.net核心的web api項目，並且我在博客控制器i中添加了一個api控制器（名稱爲BlogController）有一個get方法GetAllBlog這是我的控制器：

[Route("api/[controller]")] 
public class BlogController : Controller 
{ 
    private static Logger logger = LogManager.GetCurrentClassLogger(); 

    public IContext _context { get; set; } 
    public BlogController(IContext ctx) 
    { 
     _context = ctx; 
    } 

    [HttpGet] 
    public IEnumerable<Blog> GetAllBlog() 
    { 
     return _context.Blogs.ToList(); 
    } 
} 

這是我IContext和型號：

public interface IContext : IDisposable 
{ 
    DbSet<Blog> Blogs { get; set; } 
    DbSet<Post> Posts { get; set; } 
    int SaveChanges(); 
} 

和背景：

public class Context : DbContext, IContext 
{ 
    public Context(DbContextOptions<Context> options) : base(options) 
    { } 
    public virtual DbSet<Blog> Blogs { get; set; } 
    public virtual DbSet<Post> Posts { get; set; } 
} 

和型號：

public class Blog 
{ 
    public int BlogId { get; set; } 
    public string Name { get; set; } 
    public string Url { get; set; } 
    public DateTime? CreationDate { get; set; } 
    public virtual IList<Post> Posts { get; set; } 
} 

當我打電話GetAllBlog()我得到這個錯誤：

No database provider has been configured for this DbContext. A provider can be configured by overriding the DbContext.OnConfiguring method or by using AddDbContext on the application service provider. If AddDbContext is used, then also ensure that your DbContext type accepts a DbContextOptions object in its constructor and passes it to the base constructor for DbContext. what is the problem?

UPDATE：這是configurationservice方法Startup類：

public void ConfigureServices(IServiceCollection services) 
{ 
    var connection = @"Data Source=.;Initial Catalog=RestfullServices;Integrated Security=true"; 
    services.AddDbContext<Context>(options => options.UseSqlServer(connection)); 
    services.AddScoped<IContext>(p => new Context(new DbContextOptions<Context>())); 
    services.AddApplicationInsightsTelemetry(Configuration); 
    services.AddMvc(); 
} 

Answer 1

在配置DbContext

services.AddDbContext<Context>(options => options.UseSqlServer(connection)); 

將其配置爲使用特定的選項options.UseSqlServer(connection)

但配置範圍的背景抽象

services.AddScoped<IContext>(p => new Context(new DbContextOptions<Context>())); 

新Context當正在用一個完全不同的配置，在他之前的配置創建。

通過改變如何IContext與DI框架啓動時這樣

services.AddScoped<IContext, Context>(); 

註冊創建的Context實例時，而不是DI框架將使用AddDbContext配置，這將有你想要使用的選項從創建DbContext的實例時的配置。

的Startup.ConfigurServices最終會變成這樣......

public void ConfigureServices(IServiceCollection services) { 
    var connection = @"Data Source=.;Initial Catalog=RestfullServices;Integrated Security=true"; 
    services.AddDbContext<Context>(options => options.UseSqlServer(connection)); 
    services.AddScoped<IContext, Context>(); 
    services.AddApplicationInsightsTelemetry(Configuration); 
    services.AddMvc(); 
}