VB调用C++编写的dll（接口约定）

我会带着你远行 2021-07-26 13:38 633阅读 0赞

## dll示例代码 ##

// 32位编译(VS2017条件编译)
    #ifdef _M_IX86
    #pragma comment(linker, "/export:Send_Str_To_DLL_TEST=_Send_Str_To_DLL_TEST@4")
    #pragma comment(linker, "/export:Start_Server_CallBack=_Start_Server_CallBack@4")
    #endif // _M_IX86
    // 64位编译(VS2017条件编译)
    #ifdef _M_X64
    //#pragma comment(lib,"QDPay_mt64.lib")
    #endif // _M_X64
    
    typedef void(__stdcall  *RX_Callback)(const char * str);
    //回调函数作为参数
    int _stdcall Start_Server_CallBack(RX_Callback rx_p) { 
    	RX_Callback p_fun=rx_p;
    	p_fun("123456");
    }
    //
    // 字符串作为参数
    extern "C" _declspec(dllexport) int _stdcall  Send_Str_To_DLL_TEST(char* p) { 
    	//std::string(p).length();
    	return std::string(p).length();
    }

## VB示例代码 ##

模块代码：

'CopyMemory 内存拷贝API
    Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (Destination As Any, Source As Any, ByVal Length As Long)
    'Start_Server_CallBack
    Public Declare Sub Start_Server_CallBack Lib "C:\\Users\\Administrator\\source\\repos\\TCP_DataManager_DLL\\Debug\\TCP_DataManager_DLL.dll" (ByVal p_func As Long, ByVal result As Integer)
    
    'Send_Str_To_DLL_TEST
    Public Declare Function Send_Str_To_DLL_TEST Lib "TCP_DataManager_DLL.dll" (ByVal file_name As String) As Integer
    
    'Server_Msg_Event
    'ByRef c As String
    'ByVal c As String
    Sub Server_Msg_Event(ByVal c As Long)
      Dim msg As String
      CopyMemory msg, c, 4
      MsgBox msg   '打印服务端消息
      
    End Sub
    'Start_Server_CallBack 接口调用测试
    Public Function test()
    
       Call Start_Server_CallBack(AddressOf Server_Msg_Event)  '调用回调函数
    
    End Function

窗体代码：

Private Sub Form_Load()
    test
    End Sub