Ejemplo del método Clone (VC++)

Se aplica a: Access 2013, Office 2013

En este ejemplo se usa el método Clone para crear copias de un conjunto de registros y, después, se deja que el usuario coloque el puntero de registros de cada copia de manera independiente.

 
// BeginCloneCpp 
#import "C:\Program Files\Common Files\System\ADO\msado15.dll" no_namespace rename("EOF", "EndOfFile") 
 
#include <stdio.h> 
#include <ole2.h> 
#include <conio.h> 
#include "CloneX.h" 
 
// Function Declarations. 
inline void TESTHR(HRESULT x) {if FAILED(x) _com_issue_error(x);}; 
void CloneX(void); 
void PrintProviderError(_ConnectionPtr pConnection); 
void PrintComError(_com_error &e); 
inline char* mygets(char* strDest, int n) 
{ 
 char strExBuff[10]; 
 char* pstrRet = fgets(strDest, n, stdin); 
 
 if (pstrRet == NULL) 
 return NULL; 
 
 if (!strrchr(strDest, '\n')) 
 // Exhaust the input buffer. 
 do 
 { 
 fgets(strExBuff, sizeof(strExBuff), stdin); 
 }while (!strrchr(strExBuff, '\n')); 
 else 
 // Replace '\n' with '\0' 
 strDest[strrchr(strDest, '\n') - strDest] = '\0'; 
 
 return pstrRet; 
} 
 
/////////////////////////////////////////////////////////// 
// // 
// Main Function // 
// // 
/////////////////////////////////////////////////////////// 
void main() 
{ 
 if(FAILED(::CoInitialize(NULL))) 
 return; 
 
 CloneX(); 
 
 //Wait here for user to see the output.. 
 printf("\nPress any key to continue..."); 
 getch(); 
 ::CoUninitialize(); 
} 
 
/////////////////////////////////////////////////////////// 
// // 
// CloneX Function // 
// // 
/////////////////////////////////////////////////////////// 
 
void CloneX() 
{ 
 // Define ADO object pointers. 
 // Initialize pointers on define. 
 // These are in the ADODB:: namespace. 
 _RecordsetPtr arstStores[3]; 
 
 //Define Other Variables 
 HRESULT hr = S_OK; 
 int intLoop = 0; 
 _bstr_t strSQL; 
 _bstr_t strMessage; 
 _bstr_t strFind; 
 int intLoop1 = 0; 
 char *tempStr; 
 bool boolFlag = TRUE; 
 char m_szS_stor_name[150]; 
 
 // Assign SQL statement and connection string to variables. 
 strSQL = "SELECT stor_name FROM Stores ORDER BY stor_name"; 
 
 _bstr_t strCnn("Provider='sqloledb';Data Source='MySqlServer';" 
 "Initial Catalog='pubs';Integrated Security='SSPI';"); 
 
 try 
 { 
 // Open recordset as a static cursor type recordset. 
 arstStores[0].CreateInstance(__uuidof(Recordset)); 
 arstStores[0]->CursorType = adOpenStatic; 
 arstStores[0]->LockType = adLockBatchOptimistic; 
 
 TESTHR(arstStores[0]->Open(strSQL,strCnn, adOpenStatic, 
 adLockBatchOptimistic,adCmdText)); 
 
 // Create two clones of the original Recordset. 
 arstStores[1] = arstStores[0]->Clone(adLockUnspecified); 
 arstStores[2] = arstStores[0]->Clone(adLockUnspecified); 
 
 while (boolFlag) 
 { 
 // Loop through the array so that on each pass, 
 // the user is searching a different copy of the 
 // same Recordset. 
 for (intLoop = 1; intLoop <= 3 ; intLoop++) 
 { 
 // Ask for search string while showing where 
 // the current record pointer is for each Recordset. 
 printf("Recordsets from stores table:\n"); 
 
 _bstr_t str1 = arstStores[0]->Fields-> 
 GetItem("stor_name")->Value; 
 printf("\t1 - Original - Record pointer at %s", 
 (LPCSTR)str1); 
 
 _bstr_t str2 = arstStores[1]->Fields-> 
 GetItem("stor_name")->Value; 
 printf("\n\t2 - Clone - Record pointer at %s", 
 (LPCSTR)str2); 
 
 _bstr_t str3 = arstStores[2]->Fields-> 
 GetItem("stor_name")->Value; 
 printf("\n\t3 - Clone - Record pointer at %s", 
 (LPCSTR)str3); 
 
 printf("\n\nEnter search string for # %d, " 
 "or press Enter to quit.\n", intLoop); 
 mygets(m_szS_stor_name, 150); 
 
 // Trim the String. 
 tempStr = strtok(m_szS_stor_name, " \t"); 
 strMessage = tempStr; 
 if (tempStr == NULL) 
 { 
 boolFlag = FALSE; 
 break; 
 } 
 
 // Find the search string; if there's no 
 // match, jump to the last record. 
 intLoop1 = intLoop - 1; 
 
 arstStores[intLoop1]->Filter = "stor_name >= '" + 
 strMessage + "'"; 
 
 if (arstStores[intLoop1]->EndOfFile) 
 { 
 arstStores[intLoop1]->Filter = (long)adFilterNone; 
 arstStores[intLoop1]->MoveLast(); 
 } 
 } 
 } // End of While Loop 
 } 
 catch(_com_error &e) 
 { 
 // Notify the user of errors if any. 
 _variant_t vtConnect; 
 
 vtConnect = arstStores[0]->GetActiveConnection(); 
 
 switch(vtConnect.vt) 
 { 
 case VT_BSTR: 
 PrintComError(e); 
 break; 
 case VT_DISPATCH: 
 PrintProviderError(vtConnect); 
 break; 
 default: 
 printf("Errors occured."); 
 break; 
 } 
 } 
 
 // Clean up objects before exit. 
 if (arstStores[0]) 
 if (arstStores[0]->State == adStateOpen) 
 arstStores[0]->Close(); 
 if (arstStores[1]) 
 if (arstStores[1]->State == adStateOpen) 
 arstStores[1]->Close(); 
 if (arstStores[2]) 
 if (arstStores[2]->State == adStateOpen) 
 arstStores[2]->Close(); 
} 
 
/////////////////////////////////////////////////////////// 
// // 
// PrintProviderError Function // 
// // 
/////////////////////////////////////////////////////////// 
 
void PrintProviderError(_ConnectionPtr pConnection) 
{ 
 // Print Provider Errors from Connection object. 
 // pErr is a record object in the Connection's Error collection. 
 ErrorPtr pErr = NULL; 
 
 if( (pConnection->Errors->Count) > 0) 
 { 
 long nCount = pConnection->Errors->Count; 
 // Collection ranges from 0 to nCount -1. 
 for(long i = 0; i < nCount; i++) 
 { 
 pErr = pConnection->Errors->GetItem(i); 
 printf("Error number: %x\t%s\n", pErr->Number, 
 (LPCSTR) pErr->Description); 
 } 
 } 
}; 
 
/////////////////////////////////////////////////////////// 
// // 
// PrintComError Function // 
// // 
/////////////////////////////////////////////////////////// 
 
void PrintComError(_com_error &e) 
{ 
 _bstr_t bstrSource(e.Source()); 
 _bstr_t bstrDescription(e.Description()); 
 
 // Print Com errors. 
 printf("Error\n"); 
 printf("\tCode = %08lx\n", e.Error()); 
 printf("\tCode meaning = %s\n", e.ErrorMessage()); 
 printf("\tSource = %s\n", (LPCSTR) bstrSource); 
 printf("\tDescription = %s\n", (LPCSTR) bstrDescription); 
}; 
// EndCloneCpp 

CloneX.h

 
// BeginCloneH 
#include "icrsint.h" 
 
// This Class extracts only store name 
// from "stores" table. 
class CStores : public CADORecordBinding 
{ 
BEGIN_ADO_BINDING(CStores) 
 
 //Column stor_name is the 1st field in the recordset 
 
 ADO_VARIABLE_LENGTH_ENTRY2(1, adVarChar, m_szS_stor_name, 
 sizeof(m_szS_stor_name), lS_stor_nameStatus, FALSE) 
 
END_ADO_BINDING() 
 
public: 
 CHAR m_szS_stor_name[150]; 
 ULONG lS_stor_nameStatus; 
}; 
 
// EndCloneH