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

using System.Runtime.InteropServices;//加载非托管dll（跨平台dll）的调用类库
using System.ComponentModel;//显示win32错误代码提示
namespace DllHandle
{
   public class NotHostingDLLHandler
    {
       //kernel32.dll是Windows 9x/Me中非常重要的32位动态链接库文件，属于内核级文件。
       //它控制着系统的内存管理、数据的输入输出操作和中断处理，当Windows启动时，kernel32.dll就驻留在内存中特定的写保护区域，使别的程序无法占用这个内存区域。
        //LoadLibrary：传入dll路径，返回dll的实例指针
       [DllImport("Kernel32.dll")]
       private static extern IntPtr LoadLibrary(string path);
       //GetProcAddress:,参数lib为LoadLibrary()方法返回的值,FunName方法名，返回dll中指定的方法委托
       [DllImport("Kernel32.dll")]
       private static extern IntPtr GetProcAddress(IntPtr lib, string FunName);

       [DllImport("kernel32.dll")]
       public static extern bool FreeLibrary(IntPtr lib);


       private IntPtr libr;//指针或句柄


       public NotHostingDLLHandler(string path)
       {
           libr = LoadLibrary(path);//加载非托管dll的加载
       }

       public Delegate Invoke(string funName, Type type)
       {
           Delegate d = null;
           try
           {
               IntPtr api = GetProcAddress(libr, funName);
               d = (Delegate)Marshal.GetDelegateForFunctionPointer(api, type);//把非托管函数转化为委托
           }
           catch (Exception)
           {
               Console.WriteLine(new Win32Exception().Message);
           
           }

           return d;
       }

       ~NotHostingDLLHandler()//按位取反~
       {
           FreeLibrary(libr);
       }

      

   }
}

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

using DllHandle;
using System.Reflection;//加载托管dll（非跨平台dll）的调用类库
using System.Runtime.InteropServices;

using System.IO;

namespace DllHelper
{
    class Program
    {

        public delegate  bool DBConnect();//如果需要执行的函数有参数，可对之进行声明。
        static void Main(string[] args)
        {
 
            int index = AppDomain.CurrentDomain.BaseDirectory.IndexOf(@"\bin");
            string path = AppDomain.CurrentDomain.BaseDirectory.Substring(0, index) + "\\Dlls\\zlDrugPacker.dll";
         //  Assembly ab = DllHandler.GetUrlAssembly(path);//获取指定路径的dll对象,这里加载的是托管的dll，不是第三方的，而是.net自带的，调用方式与是否注册没关系
            //zlDrugPacker.clsDrugPacker model = new zlDrugPacker.clsDrugPacker();
            //model.DBConnect();
          

            NotHostingDLLHandler notHostdll = new NotHostingDLLHandler(path);
            
            DBConnect dbconnect = (DBConnect)notHostdll.Invoke("DBConnect", typeof(DBConnect));
           
            //show();



            Console.ReadLine();


        }
    }
}