1 #define _csharp_string extern "C" __declspec(dllexport) const char*
2 
3 _csharp_string func(){
4   return "Hi,沙奇码"; 
5 }

 1 using System;
 2 using System.Text;
 3 using System.Runtime.InteropServices;
 4 
 5 namespace ConsoleApp1
 6 {
 7    class Program
 8    {
 9       //导入dll
10       [DllImport(@"D:\Dll1.dll"), EntryPoint = "func", 
          CharSet = CharSet.Ansi, CallingConvention = CallingConvention.Cdecl]
11       //引用外部实现的函数，若C++中函数返回类型为指针，则C#中使用IntPtr作为返回类型，
         //若非指针类型，对应返回类型声明即可
12       extern static IntPtr func();
13          
14       static void Main(string[] args)
15       {
16          //使用Marshal封装的函数取指针值
17          Console.WriteLine(Marshal.PtrToStringAnsi(func()));
18       }  
19    }      
20 }