我的代码怎么了?显示未处理的异常:System.IO.FileNotFoundException

我正在学习c#,我正在尝试做一个基本的登录 Console Application 使用 Three Tier Architecture Factory Method Design Pattern 但是当我试着用 dotnet run

未处理的异常:System.IO.FileNotFoundException:无法加载 PublicKeyToken=null'。系统找不到指定的文件。 在BusinessLogic.User.getUserName() 在C:\Users\xxx\Desktop\FactoryPatternSample\FactoryMethodSampleApplication\FactoryMethod\Program.cs中的FactoryMethod.Program.Main(String[]args)处:第14行

尽管文件存在于BusinessLogic.User.getUserName()中;

伊洛金公司

public interface ILogin
    {
        bool AttemptLogin();
        string getUserName();

    }

用户.cs

using System;
using DataAccessLogic;
namespace BusinessLogic
{
    class User:ILogin
    {
       private string m_username;
       private string m_password;
       public User(string username, string password)
       {
           this.m_username = username;
           this.m_password = password;
       }
       public bool AttemptLogin()
       {
           if(m_username.Equals("abc") && m_password.Equals("abc123"))
           {
               return true;
           }
           return false;
       }
       public string getUserName()
       {
           IGetDetails objectType = GetDetails.getDetails(m_username);
           Console.WriteLine(objectType.getStudentName());
           return objectType.getStudentName();
       }
    }
}

IGetDetails.cs文件

using System;

namespace DataAccessLogic
{
    public interface IGetDetails
    {
        string getStudentName();
        string getStudentId();
    }
}

namespace DataAccessLogic
{
    public class GetDetails
    {
        public static IGetDetails getDetails(string username)
        {
            Console.WriteLine(username);
            IGetDetails objectType = null;
            objectType = new GetValue(username);
            return objectType;
        }
    }
}

获取值.cs

namespace DataAccessLogic
{
    public class GetValue:IGetDetails
    {
        private string m_username = string.Empty;
        public GetValue(string username)
        {
            this.m_username = username;
        }
        public string getStudentName()
        {
            return m_username;
        }
        public string getStudentId()
        {
            return "2205";
        }
    }

在Program.cs中

ILogin loginType = Login.attemptLogin(email, password);
        if(loginType.AttemptLogin())
        {
            Console.WriteLine("Name: "+ loginType.getUserName());
        }

如果我更改 getUserName() 方法只返回一个字符串,如“hello”,它给出了输出,但当我尝试从对象返回字符串时 IGetDetails 给出错误。

Github

任何帮助都将不胜感激。