C# 动态调用DLL库

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Runtime.InteropServices;
using System.Reflection;

namespace DLLtest
{
    class Program
    {
        static void Main(string[] args)
        {
            // 获取dlltest11.dll的文件路径
            Assembly ass = Assembly.LoadFrom("./dlltest11.dll");
            // 获取该dll中命名空间dlltest11中Class1类
            Type type = ass.GetType("dlltest11.Class1");
            // 实例化该类
            object obj = Activator.CreateInstance(type);
            // 获取该类中的方法ShowMessage
            //MethodInfo mi = type.GetMethod("ShowMessage");

            // 使用方法
            //mi.Invoke(obj, new object[1]);

            Type[] structure_Type = new Type[1];
            Object[] structure_Obj = new Object[1];

            structure_Type[0] = Type.GetType("System.String");

            Console.WriteLine("请输入数字：\n");

            string content = Console.ReadLine();

            structure_Obj[0] = content;

            if (content != "")
            {
                MethodInfo mi = type.GetMethod("ShowMessage", structure_Type);
                Object returnValue = mi.Invoke(obj, structure_Obj);
                string result = returnValue.ToString();
                Console.WriteLine("result is {0}\n", result);
            }
            else
            {
                Console.WriteLine("输入为空_________________");
            }
        }
    }
}

dll文件：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace dlltest11
{
    public class Class1
    {
        public string ShowMessage(string text)
        {
            if (text == "123")
            {
                return "PASS";
            }
            else
            {
                return "NG";
            }
        }
    }
}