在静态类中读取appsettings.json中的值

在启动过程中，应将连接字符串保存到以下位置的静态属性中： Startup

public class Startup
{
    public static string ConnectionString { get; private set; }

    public Startup(IHostingEnvironment env)
    {
        // Set up configuration sources.
        var builder = new ConfigurationBuilder()
            .AddJsonFile("appsettings.json")
            .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)
            .AddUserSecrets();

        if (env.IsDevelopment())
        {
            // For more details on using the user secret store see http://go.microsoft.com/fwlink/?LinkID=532709
            builder.AddUserSecrets();
        }

        builder.AddEnvironmentVariables();
        Configuration = builder.Build();
        ConnectionString = Configuration.Get<string>("Data:MongoDB:MongoServerSettings");
    }
    // ...
}

然后，您应该可以从任何地方访问它：

public static string GetDefaultConnectionString()
{
    return Startup.ConnectionString;
}