在ConfigureServices之后添加标识

Question

我正在尝试在ConfigureServices方法之后添加Identity。这是因为我已经在ConfigureServices方法之外注册了dbContext。因此，现在我必须在配置dbContext之后配置Identity(同样，这是我在ConfigureServices之外完成的(。我为dbContext所做的是创建了一个工厂，并将其添加到ConfigureServices:

services.AddScoped<IDbContextFactory, DbContextFactory>();

然后我使用DI将其注入控制器的构造函数：

private IDbContextFactory contextFactory;
private AppDbContext context;
public DbTestController(IDbContextFactory _contextFactory)
{
contextFactory = _contextFactory;
context = contextFactory.Create(); //Create() returns an `AppDbContext`
}

我可以对数据库执行CRUD操作，但Identity不起作用，它抛出异常：

No service for type Microsoft.AspNetCore.Identity.XXX has been registered

这是因为我在ConfigureServices中注册Identity，而没有首先设置dbContext(因为它是在ConfigureServices方法之后设置的。

services.AddIdentity<IdentityUser, IdentityRole>()
.AddEntityFrameworkStores<AppDbContext>()
.AddDefaultTokenProviders();

有没有一种方法可以像我设置dbContext一样设置标识？

编辑：DbContextFactory包括一个返回AppDbContext的Create方法。它从一些配置文件中读取用户对数据库提供程序的选择，相应地注册该提供程序，然后返回AppDbContext。以下是Create方法的代码：

public AppDbContext Create()
{
//Get this value from some configuration
string providerType = _configuration.GetValue<string>("DatabaseProvider");
//and the connection string for the database
string connectionString = _configuration.GetConnectionString(providerType);
var dbContextBuilder = new DbContextOptionsBuilder();
//Add some if else blocks here to check which provider to use
//and then call dbContextBuilder.UseABC(connectionString)
if (providerType == "MSSQL")
dbContextBuilder.UseSqlServer(connectionString);
else if (providerType == "SQLite")
dbContextBuilder.UseSqlite(connectionString);

//Create the context
context = new AppDbContext(dbContextBuilder);
return context;
}

该方法读取CCD_ 17&CCD_ 18从CCD_。这就是这个部分的样子：

"DatabaseProvider": "MSSQL", //could be MySQL, SQLite etc etc
"ConnectionStrings": {
"MSSQL": "Server=(localdb)\MSSQLLocalDB;Database=XXX_db;Trusted_Connection=True;MultipleActiveResultSets=true",
"SQLite": "Data Source=XXX_db.db"
}

Answer 1

像往常一样在ConfigureServices中注册上下文和标识，在启动时在组合根中应用所需的逻辑。

//Get this value from some configuration
string providerType = Configuration.GetValue<string>("DatabaseProvider");
//and the connection string for the database
string connectionString = Configuration.GetConnectionString(providerType);
services.AddDbContext<AppDbContext>(options => {
if (providerType == "MSSQL")
options.UseSqlServer(connectionString);
else if (providerType == "SQLite")
options.UseSqlite(connectionString);
});
services.AddIdentity<IdentityUser, IdentityRole>()
.AddEntityFrameworkStores<AppDbContext>()
.AddDefaultTokenProviders();

你需要做的是重新设计工厂

public class DbContextFactory : IDbContextFactory {
private readonly Func<AppDbContext> factory;
public DbContextFactory(Func<AppDbContext> factory) {
this.factory = factory;
}
public AppDbContext Create() {
return factory();
}
}

并相应地向工厂代表注册

services.AddScoped<IDbContextFactory, DbContextFactory>(sp => 
new DbContextFactory(() => sp.GetRequiredService<AppDbContext>()));