Ejemplo del método Supports (VC++)

Se aplica a: Access 2013, Office 2013

En este ejemplo se utiliza el método Supports para mostrar las opciones que admite un conjunto de registros que se ha abierto con diferentes tipos de cursor. Se requiere la función DisplaySupport para que este ejemplo pueda ejecutarse.

 
// BeginSupportsCpp 
#import "C:\Program Files\Common Files\System\ADO\msado15.dll" no_namespace rename("EOF", "EndOfFile") 
 
#include <stdio.h> 
#include <ole2.h> 
#include <conio.h> 
 
//Function Declarations. 
inline void TESTHR(HRESULT x) {if FAILED(x) _com_issue_error(x);}; 
void SupportsX(void); 
void DisplaySupport(_RecordsetPtr pRstTemp); 
void PrintProviderError(_ConnectionPtr pConnection); 
void PrintComError(_com_error &e); 
 
/////////////////////////////////////////////// 
// // 
// Main Function // 
// // 
/////////////////////////////////////////////// 
void main() 
{ 
 if(FAILED(::CoInitialize(NULL))) 
 return; 
 
 SupportsX(); 
 
 ::CoUninitialize(); 
} 
 
/////////////////////////////////////////////// 
// // 
// SupportsX Function // 
// // 
/////////////////////////////////////////////// 
void SupportsX(void) 
{ 
 // Define ADO object pointers. 
 // Initialize pointers on define. 
 // These are in the ADODB:: namespace. 
 _RecordsetPtr pRstTitles = NULL; 
 
 // Define Other Variables 
 HRESULT hr = S_OK; 
 
 // Assign connection string to a variable 
 _bstr_t strCnn("Provider='sqloledb';Data Source='MySqlServer';" 
 "Initial Catalog='pubs';Integrated Security='SSPI';"); 
 
 try 
 { 
 // Open a recordset from Titles table 
 TESTHR(pRstTitles.CreateInstance(__uuidof(Recordset))); 
 
 // Fill array with CursorType constants. 
 int aintCursorType[4]; 
 aintCursorType[0] = adOpenForwardOnly; 
 aintCursorType[1] = adOpenKeyset; 
 aintCursorType[2] = adOpenDynamic; 
 aintCursorType[3] = adOpenStatic; 
 
 // Open recordset using each CursorType and optimistic locking. 
 // Then call the DisplaySupport procedure to display the 
 // supported options. 
 for (int intIndex=0; intIndex <= 3; intIndex++) 
 { 
 pRstTitles->CursorType = 
 (enum CursorTypeEnum)aintCursorType[intIndex]; 
 pRstTitles->LockType = adLockOptimistic; 
 
 // Pass the Cursor type and LockType to the Recordset. 
 pRstTitles->Open ("titles", strCnn, 
 (enum CursorTypeEnum)aintCursorType[intIndex], 
 adLockOptimistic, adCmdTable); 
 
 switch(aintCursorType[intIndex]) 
 { 
 case adOpenForwardOnly: 
 printf("\nForwardOnly cursor supports:\n"); 
 break; 
 
 case adOpenKeyset: 
 printf("\nKeyset cursor supports:\n"); 
 break; 
 
 case adOpenDynamic: 
 printf("\nDynamic cursor supports:\n"); 
 break; 
 
 case adOpenStatic: 
 printf("\nStatic cursor supports:\n"); 
 break; 
 
 default : 
 break; 
 } 
 
 DisplaySupport(pRstTitles); 
 
 printf("\n\nPress any key to continue..."); 
 getch(); 
 
 //Clear the screen for the next display. 
 system("cls"); 
 } 
 } 
 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; 
 } 
 } 
 
 // Clean up objects before exit. 
 if (pRstTitles) 
 if (pRstTitles->State == adStateOpen) 
 pRstTitles->Close(); 
} 
 
/////////////////////////////////////////////// 
// // 
// DisplaySupport Function // 
// // 
/////////////////////////////////////////////// 
void DisplaySupport (_RecordsetPtr pRstTemp) 
{ 
 // Fill array with cursor option constants. 
 long alngConstants[11]; 
 alngConstants[0] = adAddNew; 
 alngConstants[1] = adApproxPosition; 
 alngConstants[2] = adBookmark; 
 alngConstants[3] = adDelete; 
 alngConstants[4] = adFind; 
 alngConstants[5] = adHoldRecords; 
 alngConstants[6] = adMovePrevious; 
 alngConstants[7] = adNotify; 
 alngConstants[8] = adResync; 
 alngConstants[9] = adUpdate; 
 alngConstants[10] = adUpdateBatch; 
 
 for(int intIndex=0; intIndex <= 10; intIndex++) 
 { 
 bool booSupports = pRstTemp-> 
 Supports( (enum CursorOptionEnum)alngConstants[intIndex] ); 
 
 if(booSupports) 
 { 
 switch(alngConstants[intIndex]) 
 { 
 case adAddNew : 
 printf("\n AddNew"); 
 break; 
 
 case adApproxPosition : 
 printf("\n AbsolutePosition and AbsolutePage"); 
 break; 
 
 case adBookmark : 
 printf("\n Bookmark"); 
 break; 
 
 case adDelete : 
 printf("\n Delete"); 
 break; 
 
 case adFind : 
 printf("\n Find"); 
 break; 
 
 case adHoldRecords : 
 printf("\n Holding Records"); 
 break; 
 
 case adMovePrevious : 
 printf("\n MovePrevious and Move"); 
 break; 
 
 case adNotify : 
 printf("\n Notifications"); 
 break; 
 
 case adResync : 
 printf("\n Resyncing data"); 
 break; 
 
 case adUpdate : 
 printf("\n Update"); 
 break; 
 
 case adUpdateBatch : 
 printf("\n Batch updating"); 
 break; 
 
 default : 
 break; 
 } 
 } 
 } 
} 
 
/////////////////////////////////////////////// 
// // 
// 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); 
} 
// EndSupportsCpp