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AbsolutePage, PageCount, and PageSize Properties Example (VC++)

This example uses the AbsolutePage, PageCount, and PageSize properties to display names and hire dates from the Employee table, five records at a time.

// BeginAbsolutePageCpp.cpp
// compile with: /EHsc
#import "msado15.dll" no_namespace rename("EOF", "EndOfFile")

#include <stdio.h>
#include <ole2.h>
#include "conio.h"
#include "icrsint.h"

// This Class extracts only fname,lastname and hire_date
class CEmployeeRs : public CADORecordBinding {
   BEGIN_ADO_BINDING(CEmployeeRs)

      // Column fname is the 2nd field in the table   
      ADO_VARIABLE_LENGTH_ENTRY2(2, adVarChar, m_szau_fname, 
      sizeof(m_szau_fname), lau_fnameStatus, FALSE)

      ADO_VARIABLE_LENGTH_ENTRY2(4, adVarChar, m_szau_lname, 
      sizeof(m_szau_lname), lau_lnameStatus, TRUE)

      ADO_VARIABLE_LENGTH_ENTRY2(8, adVarChar, m_szau_hiredate, 
      sizeof(m_szau_hiredate), lau_hiredateStatus, TRUE)

   END_ADO_BINDING()

public:
   CHAR   m_szau_lname[41];
   ULONG  lau_lnameStatus;
   CHAR   m_szau_fname[41];
   ULONG  lau_fnameStatus;
   CHAR   m_szau_hiredate[40];
   ULONG  lau_hiredateStatus;

};

// Function Declarations.
inline void TESTHR(HRESULT x) { if FAILED(x) _com_issue_error(x); };
void AbsolutePageX();
void PrintProviderError(_ConnectionPtr pConnection); 

int main() {
   if ( FAILED(::CoInitialize(NULL)) )
      return -1;

   AbsolutePageX();
   ::CoUninitialize();
}

void AbsolutePageX() {
   // Define ADO object pointers.  Initialize pointers on define.
   // These are in the ADODB::  namespace.
   _RecordsetPtr pRstEmployees = NULL;

   // Define Other Variables.    Interface Pointer declared.(VC++ Extensions)
   IADORecordBinding *picRs = NULL;
   CEmployeeRs emprs;   // C++ class object 
   HRESULT hr = S_OK;
   _bstr_t strMessage;

   // Open a recordset using a Client Cursor for the Employee Table
   _bstr_t strCnn("Provider='sqloledb'; Data Source='My_Data_Source'; Initial Catalog='pubs'; Integrated Security='SSPI';");

   try {
      // Open a recordset.
      TESTHR(hr = pRstEmployees.CreateInstance(__uuidof(Recordset)));

      // Use client cursor to enable Absoluteposition property.
      pRstEmployees->CursorLocation = adUseClient;

      // Explicitly pass the default Cursor type  and LockType to the Recordset here 
      TESTHR(hr = pRstEmployees->Open("employee", strCnn, adOpenForwardOnly, adLockReadOnly, adCmdTable));

      // Open an IADORecordBinding interface pointer for Binding Recordset to a class    
      TESTHR(hr = pRstEmployees->QueryInterface(__uuidof(IADORecordBinding), (LPVOID*)&picRs));

      // Bind the Recordset to a C++ Class here    
      TESTHR(hr = picRs->BindToRecordset(&emprs));

      // Display Names and hire dates, five records at a time
      pRstEmployees->PageSize = 5;

      int intPageCount = pRstEmployees->PageCount;

      for (int intPage = 1 ; intPage <= intPageCount ; intPage++ ) {
         pRstEmployees->put_AbsolutePage((enum PositionEnum)intPage);
         strMessage = "";

         for ( int intRecord = 1 ; intRecord <= pRstEmployees->PageSize ; intRecord++ ) {
            printf("\t%s %s %.10s\n", 
               emprs.lau_fnameStatus == adFldOK ? 
               emprs.m_szau_fname : "<NULL>",
               emprs.lau_lnameStatus == adFldOK ? 
               emprs.m_szau_lname : "<NULL>",
               emprs.lau_hiredateStatus == adFldOK ? 
               emprs.m_szau_hiredate : "<NULL>");

            pRstEmployees->MoveNext();

            if (pRstEmployees->EndOfFile)
               break;
         }
      }
   }
   catch(_com_error &e) {
      // Notify the user of errors if any.
      _variant_t vtConnect = pRstEmployees->GetActiveConnection();

      // GetActiveConnection returns connect string if connection
      // is not open, else returns Connection object.
      switch(vtConnect.vt) {
      case VT_BSTR:
         printf("Error:\n");
         printf("Code = %08lx\n", e.Error());
         printf("Message = %s\n", e.ErrorMessage());
         printf("Source = %s\n", (LPCSTR) e.Source());
         printf("Description = %s\n", (LPCSTR) e.Description());
         break;
      case VT_DISPATCH:
         PrintProviderError(vtConnect);
         break;
      default:
         printf("Errors occured.");
         break;
      }
   }
   // Clean up objects before exit.  Release the IADORecordset Interface here
   if (picRs) 
      picRs->Release();

   if (pRstEmployees)
      if (pRstEmployees->State == adStateOpen)
         pRstEmployees->Close();
}

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.
      printf("Error:\n");
      for ( long iError = 0 ; iError < nCount ; iError++) {
         pErr = pConnection->Errors->GetItem(iError);
         printf("\t Error number: %x\t%s\n", pErr->Number, (LPCSTR) pErr->Description);
      }
   }
}
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