c++ - 如何收到来自动态数据交换 (DDE) 的任何更新通知？

Question

我正在按照 How to use Dynamic Data Exchange (DDE) with Word and Excel from Visual C++ 中的示例进行操作我以某种方式设法能够从 Excel 中检索值。

现在的问题是，对于这个例子，我必须重新运行应用程序以获得必要的更新。如果 Excel 中有更新，我如何才能通知我的应用程序？ DdeAdvise?

提前致谢! Excel只是一个例子!不，我需要 DDE 而不是 COM，即使它很旧。

// DDEExample.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <windows.h> 
#include "ddeml.h"

#define PAUSE system("pause")

HDDEDATA CALLBACK DdeCallback(UINT uType, UINT uFmt, HCONV hconv,
         HSZ hsz1, HSZ hsz2, HDDEDATA hdata,
         ULONG_PTR dwData1, ULONG_PTR dwData2)
{
 printf("uType: %d", uType);
 switch(uType)
 {
  case XTYP_REQUEST:
   printf("XTYP_REQUEST\n");
  break;

 }
 return 0;
}

void DDERequest(DWORD idInst, HCONV hConv, char* szItem, char* sDesc)
{
    HSZ hszItem = DdeCreateStringHandle(idInst, szItem, 0);
    HDDEDATA hData = DdeClientTransaction(NULL,0,hConv,hszItem,CF_TEXT, 
                                 XTYP_REQUEST,5000 , NULL);
    if (hData==NULL)
    {
        printf("Request failed: %s\n", szItem);
    }
    else
    {
        char szResult[255];
        DdeGetData(hData, (unsigned char *)szResult, 255, 0);
        printf("%s%s\n", sDesc, szResult);
    }
}


int _tmain(int argc, _TCHAR* argv[])
{
 char szApp[] = "EXCEL";
 char szTopic[] = "C:\\Test.xlsx";
 char szCmd1[] = "[APP.MINIMIZE()]";
 char szItem1[] = "R1C1";  char szDesc1[] = "A1 Contains: ";


 UINT uiResult;
 DWORD m_dwDDEInstance = 0;
 uiResult = DdeInitialize(&m_dwDDEInstance, (PFNCALLBACK) &DdeCallback, APPCLASS_STANDARD|APPCMD_CLIENTONLY, 0);
 if(uiResult != DMLERR_NO_ERROR)
 {
  printf("DDE Initialization Failed: 0x%04x\n", uiResult);
  return FALSE;
 }
 printf("m_dwDDEInstance: %u\n", m_dwDDEInstance);
 //PAUSE;
 HSZ hszApp, hszTopic;
 HCONV hConv;
 hszApp = DdeCreateStringHandle(m_dwDDEInstance, szApp, 0);
 hszTopic = DdeCreateStringHandle(m_dwDDEInstance, szTopic, 0);
 hConv = DdeConnect(m_dwDDEInstance, hszApp, hszTopic, NULL);
 DdeFreeStringHandle(m_dwDDEInstance, hszApp);
 DdeFreeStringHandle(m_dwDDEInstance, hszTopic);
 if(hConv == NULL)
 {
  printf("DDE Connection Failed.\n");
 }

 DDERequest(m_dwDDEInstance, hConv, szItem1, szDesc1);
 DdeDisconnect(hConv);
 DdeUninitialize(m_dwDDEInstance);

 PAUSE;
}

Answer 1

来自 MS 平台 SDK:“客户端可以通过在对 DdeClientTransaction 的调用中指定 XTYP_ADVSTART 事务类型来请求与服务器的热建议循环。”

//#include "stdafx.h"
#include "windows.h"
#include "ddeml.h"
#include "stdio.h"

char szApp[] = "EXCEL";
char szTopic[] = "C:\\Test.xls";
char szCmd1[] = "[APP.MINIMIZE()]";
char szItem1[] = "R1C1";  char szDesc1[] = "A1 Contains: ";
char szItem2[] = "R2C1";  char szDesc2[] = "A2 Contains: ";
char szItem3[] = "R3C1";  char szData3[] = "Data from DDE Client";

HSZ hszApp, hszTopic;
DWORD idInst=0;

HDDEDATA CALLBACK DdeCallback(
    UINT uType,     // Transaction type.
    UINT uFmt,      // Clipboard data format.
    HCONV hconv,    // Handle to the conversation.
    HSZ hsz1,       // Handle to a string.
    HSZ hsz2,       // Handle to a string.
    HDDEDATA hdata, // Handle to a global memory object.
    DWORD dwData1,  // Transaction-specific data.
    DWORD dwData2)  // Transaction-specific data.
{
    if(uType==XTYP_ADVDATA && uFmt==CF_TEXT)
    {
        HSZ hszItem1 = DdeCreateStringHandle(idInst, szItem1, 0);
        HSZ hszItem2 = DdeCreateStringHandle(idInst, szItem2, 0);
        char szResult[255];
        if((!DdeCmpStringHandles(hsz1, hszTopic)) && (!DdeCmpStringHandles(hsz2, hszItem1)))
        {
            DdeGetData(hdata, (unsigned char *)szResult, 255, 0);
            printf("%s - %s\n", szItem1,szResult);
        }
        else if((!DdeCmpStringHandles(hsz1, hszTopic)) && (!DdeCmpStringHandles(hsz2, hszItem2)))
        {
            DdeGetData(hdata, (unsigned char *)szResult, 255, 0);
            printf("%s - %s\n", szItem2,szResult);
        }
    }
    return 0;
}

void DDEExecute(DWORD idInst, HCONV hConv, char* szCommand)
{
    HDDEDATA hData = DdeCreateDataHandle(idInst, (LPBYTE)szCommand,
                               lstrlen(szCommand)+1, 0, NULL, CF_TEXT, 0);
    if (hData==NULL)   {
        printf("Command failed: %s\n", szCommand);
    }
    else    {
        DdeClientTransaction((LPBYTE)hData, 0xFFFFFFFF, hConv, 0L, 0,
                             XTYP_EXECUTE, TIMEOUT_ASYNC, NULL);
    }
}

void DDERequest(DWORD idInst, HCONV hConv, char* szItem, char* sDesc)
{
    HSZ hszItem = DdeCreateStringHandle(idInst, szItem, 0);
    HDDEDATA hData = DdeClientTransaction(NULL,0,hConv,hszItem,CF_TEXT,
                                 XTYP_REQUEST,5000 , NULL);
    if (hData==NULL)
    {
        printf("Request failed: %s\n", szItem);
    }
    else
    {
        char szResult[255];
        DdeGetData(hData, (unsigned char *)szResult, 255, 0);
        printf("%s%s\n", sDesc, szResult);
    }
}

void DDEPoke(DWORD idInst, HCONV hConv, char* szItem, char* szData)
{
    HSZ hszItem = DdeCreateStringHandle(idInst, szItem, 0);
    DdeClientTransaction((LPBYTE)szData, (DWORD)(lstrlen(szData)+1),
                          hConv, hszItem, CF_TEXT,
                          XTYP_POKE, 3000, NULL);
    DdeFreeStringHandle(idInst, hszItem);
}



int main(int argc, char* argv[])
{

    char szCmd2[] = "[SELECT(\"R3C1\")][FONT.PROPERTIES(,\"Bold\")]";//[SAVE()][QUIT()]";

    //DDE Initialization
    UINT iReturn;
    iReturn = DdeInitialize(&idInst, (PFNCALLBACK)DdeCallback,
                            APPCLASS_STANDARD | APPCMD_CLIENTONLY, 0 );
    if (iReturn!=DMLERR_NO_ERROR)
    {
        printf("DDE Initialization Failed: 0x%04x\n", iReturn);
        Sleep(1500);
        return 0;
    }

    //Start DDE Server and wait for it to become idle.
    HINSTANCE hRet = ShellExecute(0, "open", szTopic, 0, 0, SW_SHOWNORMAL);
    if ((int)hRet < 33)
    {
        printf("Unable to Start DDE Server: 0x%04x\n", (UINT)hRet);
        Sleep(1500); DdeUninitialize(idInst);
        return 0;
    }
    Sleep(1000);

    //DDE Connect to Server using given AppName and topic.
    HCONV hConv;
    hszApp = DdeCreateStringHandle(idInst, szApp, 0);
    hszTopic = DdeCreateStringHandle(idInst, szTopic, 0);
    hConv = DdeConnect(idInst, hszApp, hszTopic, NULL);
    DdeFreeStringHandle(idInst, hszApp);
    DdeFreeStringHandle(idInst, hszTopic);
    if (hConv == NULL)
    {
        printf("DDE Connection Failed.\n");
        Sleep(1500); DdeUninitialize(idInst);
        return 0;
    }

    //Execute commands/requests specific to the DDE Server.
    DDEExecute(idInst, hConv, szCmd1);
    DDERequest(idInst, hConv, szItem1, szDesc1);
    DDERequest(idInst, hConv, szItem2, szDesc2);
    DDEPoke(idInst, hConv, szItem3, szData3);
    DDEExecute(idInst, hConv, szCmd2);

    HSZ hszItem = DdeCreateStringHandle(idInst, szItem1, 0);
    DdeClientTransaction(NULL,0,hConv,hszItem,CF_TEXT,
                                 XTYP_ADVSTART,5000 , NULL);


BOOL bRet;
MSG msg;

while( (bRet = GetMessage( &msg, NULL, 0, 0 )) != 0)
{
    if (bRet == -1)
    {
        // handle the error and possibly exit
    }
    else
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
}

    //DDE Disconnect and Uninitialize.
    DdeDisconnect(hConv);
    DdeUninitialize(idInst);

    Sleep(3000);
    return 1;
}

希望对你有帮助