我无法解决如何在ASP .NET Core中检索连接字符串的问题。我花了两天时间尝试所有不同的事情,但无法正常工作。
我尝试了以下方法:
ConfigurationManager.ConnectionStrings["SupplierDB"].ConnectionString
// NullReferenceException: Object reference not set to an instance of an object.
ConfigurationManager.ConnectionStrings[0].ConnectionString
// data source=.\SQLEXPRESS;Integrated Security=SSPI;AttachDBFilename=|DataDirectory|aspnetdb.mdf;User Instance=true
ConfigurationManager.AppSettings.Count.ToString();
// Returns 0
我在appsettings.json和web.config中都指定了相同的连接字符串。有人能指出我正确的方向,因为我什么都没做,所以我现在完全迷失了。
appsettings.json
{
"ConnectionStrings": {
"CustomerDB": "Data Source=(localdb)\\MSSQLLocalDB;Initial Catalog=Customer_Db;Integrated Security=True;Connect Timeout=30;Encrypt=False;TrustServerCertificate=False;ApplicationIntent=ReadWrite;MultiSubnetFailover=False",
"SupplierDB": "Data Source=(localdb)\\MSSQLLocalDB;Initial Catalog=Supplier_Db;Integrated Security=True;Connect Timeout=30;Encrypt=False;TrustServerCertificate=False;ApplicationIntent=ReadWrite;MultiSubnetFailover=False"
},
"Logging": {
"LogLevel": {
"Default": "Information",
"Microsoft": "Warning",
"Microsoft.Hosting.Lifetime": "Information"
}
},
"AllowedHosts": "*"
}
web.config
<?xml version="1.0" encoding="utf-8"?>
<configuration>
<connectionStrings>
<add name="CustomerDB" providerName="System.Data.SqlClient" connectionString="Data Source=(localdb)\MSSQLLocalDB;Initial Catalog=Customer_Db;Integrated Security=True;Connect Timeout=30;Encrypt=False;TrustServerCertificate=False;ApplicationIntent=ReadWrite;MultiSubnetFailover=False"/>
<add name="SupplierDB" providerName="System.Data.SqlClient" connectionString="Data Source=(localdb)\MSSQLLocalDB;Initial Catalog=Supplier_Db;Integrated Security=True;Connect Timeout=30;Encrypt=False;TrustServerCertificate=False;ApplicationIntent=ReadWrite;MultiSubnetFailover=False"/>
</connectionStrings>
</configuration>
您可以通过将appsettings.json复制到AppSettings
来创建此类的QuickType类:
public class AppSettings
{
public static ConnectionStrings ConnectionStrings { get; set; }
public static Logging Logging { get; set; }
public static string AllowedHosts { get; set; }
}
public class ConnectionStrings
{
public string CustomerDb { get; set; }
public string SupplierDb { get; set; }
}
public class Logging
{
public LogLevel LogLevel { get; set; }
}
public class LogLevel
{
public string Default { get; set; }
public string Microsoft { get; set; }
public string MicrosoftHostingLifetime { get; set; }
}
然后输入Startup
:
public IConfiguration Configuration { get; }
// This method gets called by the runtime. Use this method to add services to the container.
public void ConfigureServices(IServiceCollection services)
{
Configuration.Get<AppSettings>();
services.AddControllersWithViews();
}
我使用static
以便于访问,而不是通过DI注入AppSettings
。
或者如果您不想将它们全部放在一个类中,请从Microsoft签出Options pattern。
请确保您安装了以下NuGet:
Microsoft.Extensions.Configuration;
Microsoft.Extensions.Configuration.Json;
//Microsoft.Extensions.Configuration.UserSecrets; //Microsoft.Extensions.Configuration.EnvironmentVariables;
使用Microsoft.Extensions.Configuration;使用System.IO;
public static class CustomConfiguration
{
public static IConfigurationRoot config;
public static void BuildConfiguration()
{
var builder = new ConfigurationBuilder()
.SetBasePath(Directory.GetCurrentDirectory())
.AddJsonFile("appsettings.json", optional: true, reloadOnChange: true);
//.AddUserSecrets(Assembly.GetExecutingAssembly(), optional: true, reloadOnChange: true)
//.AddEnvironmentVariables();
config = builder.Build();
}
}
然后,从任意位置调用Subject方法
CustomConfiguration.BuildConfiguration();
string connectionString = CustomConfiguration.config.GetConnectionString("CustomerDB");
您可以在appsettings.json中获得连接字符串值,如下所示:
public class HomeController : Controller
{
public readonly IConfiguration _configuration;
public HomeController(IConfiguration configuration)
{
_configuration = configuration;
}
public IActionResult Index()
{
string CustomerDBConnectionString = _configuration.GetConnectionString("CustomerDB");
string SupplierDBConnectionString = _configuration.GetConnectionString("SupplierDB");
return View();
}
}