<connectionStrings>
  <add name="MySQLContext" connectionString="server=localhost;database=db;uid=root;password=xxxxxxxx" providerName="MySql.Data.MySqlClient" />
</connectionStrings>

<entityFramework codeConfigurationType="MySql.Data.Entity.MySqlEFConfiguration, MySql.Data.Entity.EF6">
    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework"/>
    <providers>
      <provider invariantName="MySql.Data.MySqlClient" type="MySql.Data.MySqlClient.MySqlProviderServices, MySql.Data.Entity.EF6"/>
      <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer"/>
</providers></entityFramework>

public class UsersContext : DbContext
    {
        public UsersContext()
            : base()
        {
        }

        // Constructor to use on a DbConnection that is already opened
        public UsersContext(DbConnection existingConnection, bool contextOwnsConnection)
           : base(existingConnection, contextOwnsConnection)
        {

        }

        public DbSet<LoginUsers> LoginUsers { get; set; }
    }

    [Table("login_users")]
    public class LoginUsers
    {
        public int Id { get; set; }
        public string Username { get; set; }
        public string Password { get; set; }
        public string Name { get; set; }
        public DateTime Created_At { get; set; }
        public bool Active { get; set; }
    }

private static string connectionString = ConfigurationManager.ConnectionStrings["MySQLContext"].ConnectionString;

    public static bool RegisterUser(string name, string username, string password, out string errorMessage)
    {
        string hashedPassword = SHA256Encrypt(password);

        using (MySqlConnection connection = new MySqlConnection(connectionString))
        {
            connection.Open();
            MySqlTransaction transaction = connection.BeginTransaction();

            try
            {
                // DbConnection that is already opened
                using (UsersContext context = new UsersContext(connection, false))
                {
                    // Passing an existing transaction to the context
                    context.Database.UseTransaction(transaction);

                    context.LoginUsers.Add(new LoginUsers()
                    {
                        Name = name,
                        Username = username,
                        Password = hashedPassword,
                        Created_At = DateTime.UtcNow,
                        Active = true
                    });
                    context.SaveChanges();
                }

                errorMessage = "";
                transaction.Commit();
                return true;
            }
            catch (Exception ex)
            {
                transaction.Rollback();
                errorMessage = "Contain error";
                return false;
            }
        }
    }

context.LoginUsers.Add(new LoginUsers()
                    {
                        Name = name,
                        Username = username,
                        Password = hashedPassword,
                        Created_At = DateTime.UtcNow,
                        Active = true
                    });

DEFINER = `admin`@`%`

connectionString="server=localhost;user id=myUserId;Password=*****;database=mydatabase; Allow User Variables=True"