services.AddDbContext<MarketDbContext>((serviceProvider, dbContextBuilder) =>
            {
                var connectionStringTemplate = Configuration.GetConnectionString("Connection");
                var httpContextAccessor = serviceProvider.GetRequiredService<IHttpContextAccessor>();
                var dbName = httpContextAccessor.HttpContext.Session.GetString("databasename");
                var connectionString = connectionStringTemplate.Replace("{db_Name}", dbName);
                dbContextBuilder.UseSqlServer(connectionString);
            });

HttpContext.Session.SetString("databasename", "DB1399");

                var httpContextAccessor = serviceProvider.GetRequiredService<IHttpContextAccessor>();