Exemple de propriétés CursorType, LockType et EditMode (VC++)

Cet exemple montre comment définir les propriétés CursorType et LockType avant d’ouvrir un Recordset. Il affiche également la valeur de la propriété EditMode dans différentes conditions. La fonction EditModeOutput est requise pour que cette procédure s’exécute.

Exemple

// CursorType_LockType_EditMode_Property_Example.cpp  
// compile with: /EHsc  
#import "msado15.dll" no_namespace rename("EOF", "EndOfFile")  
  
#include <ole2.h>  
#include <stdio.h>  
#include <conio.h>  
  
// Function declaration  
inline void TESTHR(HRESULT x) { if FAILED(x) _com_issue_error(x); };  
void EditModeX();  
void EditModeOutput(char *, int);  
void PrintProviderError(_ConnectionPtr pConnection);  
void PrintComError(_com_error &e);  
  
int main() {  
   if ( FAILED(::CoInitialize(NULL)) )  
      return -1;  
  
   EditModeX();  
   ::CoUninitialize();  
}  
  
void EditModeX() {  
   // Define ADO object pointers.  Initialize pointers on define.  
   // These are in the ADODB:: namespace.  
   _RecordsetPtr pRstEmployees = NULL;  
   _ConnectionPtr pConnection = NULL;  
  
   HRESULT hr = S_OK;  
  
   _bstr_t strCnn("Provider='sqloledb'; Data Source='My_Data_Source'; Initial Catalog='pubs'; Integrated Security='SSPI';");  
  
   try {  
      // Open a connection  
      TESTHR(pConnection.CreateInstance(__uuidof(Connection)));  
      hr = pConnection->Open(strCnn, "", "", adConnectUnspecified);  
  
      // Open recordset with data from employee table   
      TESTHR(pRstEmployees.CreateInstance(__uuidof(Recordset)));  
  
      pRstEmployees->CursorLocation = adUseClient;  
      pRstEmployees->CursorType = adOpenStatic;  
      pRstEmployees->LockType = adLockBatchOptimistic;  
  
      pRstEmployees->Open("employee", _variant_t((IDispatch *) pConnection,true),  
         adOpenStatic, adLockBatchOptimistic, adCmdTable);  
  
      // Show the EditMode property under different editing states.  
      pRstEmployees->AddNew ();  
      pRstEmployees->Fields->Item["emp_id"]->Value = (_bstr_t)("T-T55555M");  
      pRstEmployees->Fields->Item["fname"]->Value = (_bstr_t)("temp_fname");  
      pRstEmployees->Fields->Item["lname"]->Value = (_bstr_t)("temp_lname");  
      EditModeOutput("After AddNew: ", pRstEmployees->EditMode);  
  
      pRstEmployees->UpdateBatch(adAffectCurrent);  
      EditModeOutput("After Update: ", pRstEmployees->EditMode);  
  
      pRstEmployees->Fields->Item["fname"]->Value = (_bstr_t)("test");  
      EditModeOutput("After Edit: ", pRstEmployees->EditMode);  
  
      // Delete new record because this is a demonstration.  
      pConnection->Execute("DELETE FROM employee WHERE emp_id = 'T-T55555M'",   
         NULL, adCmdText);  
   }  
   catch(_com_error &e) {  
      // Display errors, if any. Pass connection pointer accessed from the Recordset.  
      PrintProviderError(pConnection);  
      PrintComError(e);  
   }  
  
   // Clean up objects before exit.  
   if (pRstEmployees)  
      if (pRstEmployees->State == adStateOpen)  
         pRstEmployees->Close();  
   if (pConnection)  
      if (pConnection->State == adStateOpen)  
         pConnection->Close();  
}  
  
void EditModeOutput(char *strTemp, int intEditMode) {  
   // Print report based on the value of the EditMode property.  
   printf("\n%s", strTemp);  
   printf("\n  EditMode = ");  
  
   switch (intEditMode) {  
   case adEditNone :  
      printf("adEditNone");  
      break;  
   case adEditInProgress :  
      printf("adEditInProgress");  
      break;  
   case adEditAdd :  
      printf("adEditAdd");  
      break;  
   }  
}  
  
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("\n\t Error number: %x\t%s\n", pErr->Number, (LPCSTR)pErr->Description);  
      }  
   }  
}  
  
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);  
}  

After AddNew:
EditMode = adEditAdd
After Update:
EditMode = adEditNone
After Edit:
EditMode = adEditInProgress

Voir aussi

CursorType, propriété (ADO)
EditMode, propriété
LockType, propriété (ADO)
Recordset, objet (ADO)