如何在.NETCore 中读取连接字符串？

可以使用配置扩展方法: getConnectionString (“ DefaultConnection”)

Https://docs.asp.net/projects/api/en/latest/autoapi/microsoft/Extensions/Configuration/ConfigurationExtensions/index.html#microsoft。扩展。配置。配置/扩展

您可以使用 GetConnectionString 扩展方法来实现这一点:

string conString = Microsoft
.Extensions
.Configuration
.ConfigurationExtensions
.GetConnectionString(this.Configuration, "DefaultConnection");


System.Console.WriteLine(conString);

或者用于 DI 的结构化类:

public class SmtpConfig
{
public string Server { get; set; }
public string User { get; set; }
public string Pass { get; set; }
public int Port { get; set; }
}

创业:

public IConfigurationRoot Configuration { get; }




// This method gets called by the runtime. Use this method to add services to the container.
public void ConfigureServices(IServiceCollection services)
{
// http://developer.telerik.com/featured/new-configuration-model-asp-net-core/
// services.Configure<SmtpConfig>(Configuration.GetSection("Smtp"));
Microsoft.Extensions.DependencyInjection.OptionsConfigurationServiceCollectionExtensions.Configure<SmtpConfig>(services, Configuration.GetSection("Smtp"));

然后是家庭控制器:

public class HomeController : Controller
{


public SmtpConfig SmtpConfig { get; }
public HomeController(Microsoft.Extensions.Options.IOptions<SmtpConfig> smtpConfig)
{
SmtpConfig = smtpConfig.Value;
} //Action Controller




public IActionResult Index()
{
System.Console.WriteLine(SmtpConfig);
return View();
}

在 appsetings.json:

"ConnectionStrings": {
"DefaultConnection": "Server=(localdb)\\mssqllocaldb;Database=aspnet-WebApplica71d622;Trusted_Connection=True;MultipleActiveResultSets=true"
},


"Smtp": {
"Server": "0.0.0.1",
"User": "user@company.com",
"Pass": "123456789",
"Port": "25"
}

我发现解决这个问题的方法是在 Startup 的构建器中使用 AddJsonFile (这允许它找到存储在 appsetings.json 文件中的配置) ，然后使用它来设置 private _ config 变量

public Startup(IHostingEnvironment env)
{
var builder = new ConfigurationBuilder()
.SetBasePath(env.ContentRootPath)
.AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
.AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)
.AddEnvironmentVariables();
_config = builder.Build();
}

然后我可以设置配置字符串如下:

var connectionString = _config.GetConnectionString("DbContextSettings:ConnectionString");

这是在 dotnet 核心1.1

公布的答案是好的，但没有直接回答我有关读取连接字符串的相同问题。通过大量的搜索，我找到了一种稍微简单一点的方法。

在 Startup.cs 中

public void ConfigureServices(IServiceCollection services)
{
...
// Add the whole configuration object here.
services.AddSingleton<IConfiguration>(Configuration);
}

在控制器中，为配置添加一个字段，并在构造函数上为其添加一个参数

private readonly IConfiguration configuration;


public HomeController(IConfiguration config)
{
configuration = config;
}

现在，在视图代码中，您可以这样访问它:

connectionString = configuration.GetConnectionString("DefaultConnection");

更多信息见链接: Https://learn.microsoft.com/en-us/ef/core/miscellaneous/connection-strings

JSON

    {
"ConnectionStrings": {
"BloggingDatabase": "Server=(localdb)\\mssqllocaldb;Database=EFGetStarted.ConsoleApp.NewDb;Trusted_Connection=True;"
},
}

C # Startup.cs

public void ConfigureServices(IServiceCollection services)
{
services.AddDbContext<BloggingContext>(options =>
options.UseSqlServer(Configuration.GetConnectionString("BloggingDatabase")));
}

编辑: aspnetcore，从3.1开始: Https://learn.microsoft.com/en-us/aspnet/core/fundamentals/configuration/?view=aspnetcore-3.1

我有一个数据访问库，可以同时使用.net 核心和.net 框架。

魔术开始了。Net 核心项目将连接字符串保存在一个名为“ app.config”的 xml 文件中(同样适用于 web 项目) ，并将其标记为“复制到输出目录”,

<?xml version="1.0" encoding="utf-8"?>
<configuration>
<connectionStrings>
<add name="conn1" connectionString="...." providerName="System.Data.SqlClient" />
</connectionStrings>
</configuration>

ConfigurationManager.ConnectionStrings-将读取连接字符串。

    var conn1 = ConfigurationManager.ConnectionStrings["conn1"].ConnectionString;

还有一个办法。在我的例子中，你可以看到存储库类中的一些业务逻辑，我在 ASP 依赖注入中使用这些逻辑。NET MVC Core 3.1.

在这里，我想获得 connectiongString的业务逻辑，因为可能另一个存储库可以访问另一个数据库。

此模式允许您在相同的业务逻辑存储库中访问不同的数据库。

C #

public interface IStatsRepository
{
IEnumerable<FederalDistrict> FederalDistricts();
}


class StatsRepository : IStatsRepository
{
private readonly DbContextOptionsBuilder<EFCoreTestContext>
optionsBuilder = new DbContextOptionsBuilder<EFCoreTestContext>();
private readonly IConfigurationRoot configurationRoot;


public StatsRepository()
{
IConfigurationBuilder configurationBuilder = new ConfigurationBuilder().SetBasePath(Environment.CurrentDirectory)
.AddJsonFile("appsettings.json", optional: true, reloadOnChange: true);
configurationRoot = configurationBuilder.Build();
}


public IEnumerable<FederalDistrict> FederalDistricts()
{
var conn = configurationRoot.GetConnectionString("EFCoreTestContext");
optionsBuilder.UseSqlServer(conn);


using (var ctx = new EFCoreTestContext(optionsBuilder.Options))
{
return ctx.FederalDistricts.Include(x => x.FederalSubjects).ToList();
}
}
}

Appsettings.json

{
"Logging": {
"LogLevel": {
"Default": "Information",
"Microsoft": "Warning",
"Microsoft.Hosting.Lifetime": "Information"
}
},
"AllowedHosts": "*",
"ConnectionStrings": {
"EFCoreTestContext": "Data Source=DESKTOP-GNJKL2V\\MSSQLSERVER2014;Database=Test;Trusted_Connection=True;MultipleActiveResultSets=true"
}
}

NET Core (在我的情况下 < strong > 3.1 )为我们提供了 构造函数注入控制器，因此您可以简单地添加以下构造函数:

[Route("api/[controller]")]
[ApiController]
public class TestController : ControllerBase
{
private readonly IConfiguration m_config;


public TestController(IConfiguration config)
{
m_config = config;
}


[HttpGet]
public string Get()
{
//you can get connection string as follows
string connectionString = m_config.GetConnectionString("Default")
}
}

下面是 appsetings.json 可能的样子:

{
"ConnectionStrings": {
"Default": "YOUR_CONNECTION_STRING"
}
}

在3.1中，已经为“ ConnectionStrings”定义了一个部分

System.Configuration

定义 :

  "ConnectionStrings": {
"ConnectionString": "..."
}

登记册 :

public void ConfigureServices(IServiceCollection services)
{
services.Configure<ConnectionStringSettings>(Configuration.GetSection("ConnectionStrings"));
}

注射 :

public class ObjectModelContext : DbContext, IObjectModelContext
{


private readonly ConnectionStringSettings ConnectionStringSettings;


...


public ObjectModelContext(DbContextOptions<ObjectModelContext> options, IOptions<ConnectionStringSettings> setting) : base(options)
{
ConnectionStringSettings = setting.Value;
}


...
}

使用 :

   public static void ConfigureContext(DbContextOptionsBuilder optionsBuilder, ConnectionStringSettings connectionStringSettings)
{
if (optionsBuilder.IsConfigured == false)
{
optionsBuilder.UseLazyLoadingProxies()
.UseSqlServer(connectionStringSettings.ConnectionString);
}
}