代码：

using System;
using System.Collections.Generic;
using System.Configuration;
using System.Linq;
using System.Reflection;
using System.Text;


namespace Builder
{
    class Program
    {
        static void Main(string[] args)
        {
            FoodManager foodManager = new FoodManager();

            Builder instance;

            Console.WriteLine("please enter food no:");

            string No = Console.ReadLine();

            string foodType = ConfigurationManager.AppSettings["No"+No];

            instance = (Builder)Assembly.Load("Builder").CreateInstance("Builder." + foodType);

            foodManager.Construct(instance);

            Food food = instance.GetFood();

            food.Show();

            Console.ReadLine();
        }
    }
}

错误信息：
System.Configuration.ConfigurationErrorsException
HResult=0x80131902
Message=配置系统未能初始化
Source=System.Configuration
StackTrace:
at System.Configuration.ClientConfigurationSystem.EnsureInit(String configKey)
at System.Configuration.ClientConfigurationSystem.PrepareClientConfigSystem(String sectionName)
at System.Configuration.ClientConfigurationSystem.System.Configuration.Internal.IInternalConfigSystem.GetSection(String sectionName)
at System.Configuration.ConfigurationManager.get_AppSettings()
at Builder.Program.Main(String[] args) in D:\work\WebApplication1\Builder\Program.cs:line 23

Inner Exception 1:
ConfigurationErrorsException: 无法识别的配置节 AppSettings。 (D:\work\WebApplication1\Builder\bin\Debug\Builder.exe.Config line 6)

我想问一下这个错误怎么解决呢？