首先，在使用Identity的DbContext之前，需要先安装Microsoft.AspNetCore.Identity.EntityFrameworkCore包。接着，在Startup.cs文件中，将AddDbContext方法替换为AddDbContextPool，并添加UseSqlServer方法以指定连接字符串。最后，在应用程序的构造函数中将DbContext注入依赖项注入容器中，以便在控制器中使用。

代码示例：

//安装Microsoft.AspNetCore.Identity.EntityFrameworkCore包 dotnet add package Microsoft.AspNetCore.Identity.EntityFrameworkCore

//Startup.cs文件中的配置 public void ConfigureServices(IServiceCollection services) { // 使用AddDbContextPool方法替换AddDbContext services.AddDbContextPool(options => options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));

services.AddIdentity()
    .AddEntityFrameworkStores()
    .AddDefaultTokenProviders();

services.AddMvc();

}

//构造函数中的注入 public class AccountController : Controller { private readonly UserManager _userManager; private readonly SignInManager _signInManager; private readonly ILogger _logger; private readonly AppDbContext _dbContext;

public AccountController(
    UserManager userManager,
    SignInManager signInManager,
    ILogger logger,
    AppDbContext dbContext)
{
    _userManager = userManager;
    _signInManager = signInManager;
    _logger = logger;
    _dbContext = dbContext;
}

// 控制器中的DbContext使用
public async Task Index()
{
    var users = await _dbContext.Users.ToListAsync();
    return View(users);
}

}