json文件，net core 2 讀取appsettings.json

問：

.Net Core: Application startup exception: System.IO.FileNotFoundException: The configuration file 'appsettings.json' was not found and is not optional.

答：

問題代碼：

public Startup()

{

var builder = new ConfigurationBuilder().AddJsonFile("AppSetting.json");

Configuration = builder.Build();

}

正確代碼：

public Startup(IHostingEnvironment environment)

{

var builder = new ConfigurationBuilder().SetBasePath(environment.ContentRootPath).AddJsonFile("AppSetting.json");

Configuration = builder.Build();

}

原文：https://www.cnblogs.com/icebutterfly/p/6797099.html

問題沒有解決，只好搜索繼續

找到https://www.cnblogs.com/OpenCoder/p/9761067.html

static void Main(string[] args)
{
var builder = new ConfigurationBuilder()
.SetBasePath(Directory.GetCurrentDirectory())
.AddJsonFile("appsettings.json", optional: true, reloadOnChange: true);

IConfigurationRoot configuration = builder.Build();

Console.WriteLine(configuration.GetConnectionString("Storage"));
Console.WriteLine(configuration.GetSection("ConnectionStrings:Storage").Value);
}

?

自己webapi程序不從Startup.cs讀取，驗證后修改如下
??????? protected static IConfiguration Configuration { get; set; }
??????? protected static string connection { get; set; }
??????? static DataManager()
??????? {
??????????? string ss = AppContext.BaseDirectory;
??????????? string aa = Directory.GetCurrentDirectory();????? ?
??????????? var builder = new ConfigurationBuilder()
???????????????????? .SetBasePath(AppContext.BaseDirectory)
???????????????????? .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true);
??????????? Configuration = builder.Build();
??????????? connection = Configuration.GetConnectionString("DefaultConnection");
??????? }