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Status Property Example (VC++)

This example uses the Status property to display which records have been modified in a batch operation before a batch update has occurred.

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

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

// This class extracts title_id and type from titles table.
class CTitleRs : public CADORecordBinding {
   BEGIN_ADO_BINDING(CTitleRs)
      // Column title_id is the 1st field in the table
      ADO_VARIABLE_LENGTH_ENTRY2(1, adVarChar, m_szt_Title_id, sizeof(m_szt_Title_id), lt_Title_idStatus, FALSE)

      // Column type is the 3rd field in the table
      ADO_VARIABLE_LENGTH_ENTRY2(3, adVarChar, m_szt_Type, sizeof(m_szt_Type), lt_TypeStatus, TRUE)

END_ADO_BINDING()

public:
   CHAR m_szt_Title_id[7];
   ULONG lt_Title_idStatus;
   CHAR m_szt_Type[13];
   ULONG lt_TypeStatus;
};

// Function declarations
inline void TESTHR(HRESULT x) {if FAILED(x) _com_issue_error(x);};
void StatusX(void);
void PrintProviderError(_ConnectionPtr pConnection);
void PrintComError(_com_error &e);

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

   StatusX();

   ::CoUninitialize();
}

void StatusX() {
   HRESULT  hr = S_OK;

   // Define string variables.
   _bstr_t strCnn("Provider='sqloledb'; Data Source='My_Data_Source'; Initial Catalog='pubs'; Integrated Security='SSPI';");

   // Define ADO object pointers.
   // Initialize pointers on define.
   // These are in the ADODB::  namespace.
    IADORecordBinding *picRs = NULL;   // Interface Pointer Declared
    CTitleRs titlers;   // C++ Class Object
   _RecordsetPtr pRstTitles = NULL;
   LPSTR p_TempStr = NULL;
   char * token1;

   try {
      // Open recordset for batch update
      TESTHR(hr = pRstTitles.CreateInstance(__uuidof(Recordset)));
      pRstTitles->CursorType = adOpenKeyset;
      pRstTitles->LockType = adLockBatchOptimistic;
      pRstTitles->Open ("titles", strCnn, adOpenKeyset, adLockBatchOptimistic, adCmdTable);

      // Open an IADORecordBinding interface pointer which 
      // we will use for binding Recordset to a class.
      TESTHR(hr = pRstTitles->QueryInterface(__uuidof(IADORecordBinding),(LPVOID*)&picRs));

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

      p_TempStr = (LPSTR) malloc(sizeof(titlers.m_szt_Type));

      // Change the type of psychology titles.
      while (!(pRstTitles->EndOfFile)) {
         // Set the final character of the destination string to NULL.
         p_TempStr[sizeof(titlers.m_szt_Type) - 1] = '\0';

         // The source string will get truncated if its length is 
         // longer than the length of the destination string minus one.
         strncpy_s(p_TempStr,  sizeof(titlers.m_szt_Type), strtok_s(titlers.m_szt_Type, " ", &token1), sizeof(titlers.m_szt_Type) - 1);
         
         // Compare the type of psychology titles
         if (!strcmp(p_TempStr,"psychology"))
               // Copy "self_help" title field
               pRstTitles->Fields->GetItem("type")->Value = (_bstr_t) ("self_help");
         pRstTitles->MoveNext();
      }

      // Display Title ID and status
      pRstTitles->MoveFirst();
      while ( !(pRstTitles->EndOfFile) ) {
         if ( pRstTitles->Status == adRecModified )
            printf("%s - Modified\n",titlers.lt_Title_idStatus == adFldOK ? titlers.m_szt_Title_id : "<NULL>");
         else
            printf("%s\n",titlers.lt_Title_idStatus == adFldOK ? titlers.m_szt_Title_id : "<NULL>");
         pRstTitles->MoveNext();
      }
   }

   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;
      }
   }

   // Deallocate the memory
   if (p_TempStr)
      free(p_TempStr);

   if (pRstTitles)
      if (pRstTitles->State == adStateOpen) {
         // Cancel the update because this is a demonstration.
         pRstTitles->CancelBatch(adAffectAll);
         pRstTitles->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.
      for (long i = 0; i < nCount; i++) {
         pErr = pConnection->Errors->GetItem(i);
         printf("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);
}
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