略短的版本，原理同上...

A slightly shorter version based on the same principle as above...

public Startup(IConfiguration configuration)
{
    Configuration = configuration;
    StaticConfig = configuration;
}

public static IConfiguration StaticConfig { get; private set; }

在另一个静态类中使用:

To use in another static class:

string connString = Startup.StaticConfig.GetConnectionString("DefaultConnection");