小编use*_*447的帖子

我正在尝试从中读取连接字符串，appsettings.json并且正在使用：

services.AddSingleton(Configuration);

启动时的这一行抛出空值。我对core2.0很陌生。有人可以告诉我缺少什么吗？

我的启动：

public class Startup
{
    public static string ConnectionString { get; private set; }
    public IConfiguration Configuration { get; }
    public void ConfigureServices(IServiceCollection services)
    {
        services.AddMvc();
        services.AddSingleton(Configuration);
        services.AddSingleton<IConfiguration>(Configuration);
    }

    public void Configure(IApplicationBuilder app, IHostingEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }

        app.UseMvc();
    }
}

我的控制器：

public class CreateController : Controller
{
    public IConfiguration _ConnectionString;
    public CreateController(IConfiguration configuration)
    {
        _ConnectionString = configuration;
    }

    public IEnumerable<string> Get()
    {
        Markets();
    }

    public string Markets()
    {
        using(SqlConnection con = …