如何在类中获取 ConnectionString 表单 appsettings.json? [英] How can I get ConnectionString form appsettings.json in a class?

问题描述

我试图连接到我的数据库而不对连接字符串进行硬编码.这就是我想出来的，有没有什么聪明的方法来获取ConnectionString?

I am trying to connect to my database without hardcoding the connectionstring. This is what Ive come up with, is there any smart way to get the ConnectionString?

SecurityDAO 类:

SecurityDAO class:

public class SecurityDAO
    {
        internal bool FindByUser(UserModel user)
        {
            string connectionString = "";
            bool success = false;

            string queryString = "SELECT * FROM users WHERE username = @username AND password = @password";

            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                MySqlCommand command = new MySqlCommand(queryString, connection);

                command.Parameters.Add("@username", MySqlDbType.VarChar, 50).Value = user.Username;
                command.Parameters.Add("@password", MySqlDbType.VarChar, 50).Value = user.Password;

                try
                {
                    connection.Open();
                    MySqlDataReader reader = command.ExecuteReader();

                    if (reader.HasRows)
                    {
                        success = true;
                    }
                    else
                    {
                        success = false;
                    }
                }
                catch (Exception ex)
                {
                    throw ex;
                }
            }
            return success;
        }
    }

SecurityService 类:

SecurityService class:

public class SecurityService
    {
        SecurityDAO daoService = new SecurityDAO();

        public bool Authenticate(UserModel user)
        {
            return daoService.FindByUser(user);
        }
    }

推荐答案

您可以在使用 SecurityService 的地方使用 DI 获取 IConfiguration 并将 IConfiguration 传递给 SecurityService.Authenticate.这是一个演示:

You can use DI to get IConfiguration in somewhere you use SecurityService and pass IConfiguration to SecurityService.Authenticate.Here is a demo:

Startup.cs:

Startup.cs:

public void ConfigureServices(IServiceCollection services)
        {
            ...

            services.AddSingleton<IConfiguration>(Configuration);
           
            services.AddScoped<SecurityService, SecurityService>();

        }

控制器:

public class Test2Controller : Controller
    {
        IConfiguration _Configuration;
        SecurityService _securityService;
        public Test2Controller(IConfiguration Configuration, SecurityService securityService) {
            _Configuration = Configuration;
            _securityService = securityService;
        }
        public IActionResult Index()
        {
            var s=_securityService.Authenticate(new UserModel(), _Configuration);
            return Ok();
        }
    }

安全服务:

SecurityDAO daoService = new SecurityDAO();

        public bool Authenticate(UserModel user,IConfiguration Configuration)
        {
            return daoService.FindByUser(user, Configuration);
        }

SecurityDAO:

SecurityDAO:

public class SecurityDAO
    {
        internal bool FindByUser(UserModel user, IConfiguration Configuration)
        {
            string connectionString = Configuration["ConnectionStrings:DefaultConnection"];
            return true;
        }
    }

结果:

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