c# - EF-core OnModelCreating 方法中的依赖注入

Question

我想OnModelCreating在DbContext. 我需要做什么？

DbContext我可以通过构造函数注入服务。但它似乎不够有效，因为该方法在应用程序启动时被调用一次，我必须为此增加整个 DbContext 类。

public PortalContext(DbContextOptions<PortalContext> options, IPasswordService passwordService) : base(options)
{
    this._passwordService = passwordService;
}

...

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    ...
    entity<User>().HasData(
     new User
     {
       UserName = "admin",
       Password = this._passwordService.EncryptPassword("passw0rd");
     }
    );
    ...
}

上面的代码可以替换为：

public PortalContext(DbContextOptions<PortalContext> options) : base(options)
{
}

...

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    ...
    var passwordService = GetPasswordService(); // How?
    entity<User>().HasData(
     new User
     {
       UserName = "admin",
       Password = passwordService.EncryptPassword("passw0rd");
     }
    );
    ...
}

标签： c#dependency-injection.net-coreef-core-2.2

Answer 1

采用

this.Database.GetService<IPasswordService>();

它是一种扩展方法，位于Microsoft.EntityFrameworkCore.Infrastructure命名空间中