Resync-Methode (Beispiel) (VC++)

Gilt für: Access 2013, Office 2013

In diesem Beispiel wird die Verwendung der Resync-Methode zum Aktualisieren von Daten in einer statischen Datensatzgruppe veranschaulicht.

 
// BeginResyncCpp 
#import "c:\Program Files\Common Files\System\ADO\msado15.dll" no_namespace rename("EOF", "EndOfFile") 
 
#include <ole2.h> 
#include <stdio.h> 
#include <conio.h> 
 
// Function declarations 
inline void TESTHR(HRESULT x) {if FAILED(x) _com_issue_error(x);}; 
void ResyncX(void); 
void PrintProviderError(_ConnectionPtr pConnection); 
void PrintComError(_com_error &e); 
 
///////////////////////////// 
// // 
// Main Function // 
// // 
///////////////////////////// 
 
void main() 
{ 
 if(FAILED(::CoInitialize(NULL))) 
 return; 
 
 ResyncX(); 
 
 ::CoUninitialize(); 
} 
 
///////////////////////////////// 
// // 
// ResyncX Function // 
// // 
///////////////////////////////// 
 
void ResyncX(void) 
{ 
 HRESULT hr = S_OK; 
 
 // Define string variables. 
 _bstr_t strCnn("Provider='sqloledb';Data Source='MySqlServer';" 
 "Initial Catalog='pubs';Integrated Security='SSPI';"); 
 
 // Define ADO object pointers. 
 // Initialize pointers on define. 
 // These are in the ADODB:: namespace. 
 _RecordsetPtr pRstTitles = NULL; 
 
 try 
 { 
 // Open recordset for titles table. 
 TESTHR(pRstTitles.CreateInstance(__uuidof(Recordset))); 
 pRstTitles->CursorLocation = adUseClient; 
 pRstTitles->CursorType = adOpenStatic; 
 pRstTitles->LockType = adLockBatchOptimistic; 
 pRstTitles->Open ("titles",strCnn, 
 adOpenStatic, adLockBatchOptimistic, adCmdTable); 
 
 // Change the type of the first title in the recordset. 
 pRstTitles->Fields->GetItem("type")->Value = 
 (_bstr_t) ("database"); 
 
 // Display the results of the change. 
 printf("\nBefore resync: \n\n"); 
 
 printf("Title - %s\n\n",(LPSTR) (_bstr_t) pRstTitles-> 
 Fields->GetItem("title")->Value); 
 
 printf("Type - %s\n\n",(LPSTR) (_bstr_t) pRstTitles-> 
 Fields->GetItem("type")->Value); 
 
 // Resync with database. 
 pRstTitles->Resync(adAffectAll,adResyncAllValues); 
 
 // Display the results of the resynch. 
 printf("\n\nAfter resync: \n\n"); 
 
 printf("Title - %s\n\n",(LPSTR) (_bstr_t) pRstTitles-> 
 Fields->GetItem("title")->Value); 
 
 printf("Type - %s\n\n",(LPSTR) (_bstr_t) pRstTitles-> 
 Fields->GetItem("type")->Value); 
 } 
 catch (_com_error &e) 
 { 
 // Notify the user of errors if any. 
 // Pass a connection pointer accessed from the Recordset. 
 _variant_t vtConnect = pRstTitles->GetActiveConnection(); 
 
 // GetActiveConnection returns connect string if connection 
 // is not open, else returns Connection object. 
 switch(vtConnect.vt) 
 { 
 case VT_BSTR: 
 PrintComError(e); 
 break; 
 case VT_DISPATCH: 
 PrintProviderError(vtConnect); 
 break; 
 default: 
 printf("Errors occured."); 
 break; 
 } 
 } 
 
 if (pRstTitles) 
 if (pRstTitles->State == adStateOpen) 
 { 
 pRstTitles->CancelBatch(adAffectAll); 
 pRstTitles->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("\t 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); 
} 
// EndResyncCpp