IRowPosition Code Example

The following code fragment shows how a consumer might use IRowPosition when traversing a rowset:

// Code to generate a pRowset

#include "msdaguid.h"
…
IRowPosition * pRowPosition = NULL;
HRESULT hr;

hr = CoCreateInstance(CLSID_OLEDB_ROWPOSITIONLIBRARY, NULL, 
      CLSCTX_INPROC_SERVER, IID_IRowPosition,
      (LPVOID *)&pRowPosition);
if (FAILED(hr))
      return hr;

hr = pRowPosition->Initialize(pRowset);   // Initialize with pRowset
if (FAILED(hr))
      {
      pRowPosition->Release();
      return hr;
      }

// Read the rows--100 rows at a time into the rowset.
While(SUCCEEDED(hr = pRowset->GetNextRows(NULL, 0, 100, &cRowsObtained,    &rghRows)) &&    cRowsObtained) 
   {
      for(irow = 0; irow < cRowsObtained; irow++) 
      {
      // GetData copies the rows into the local buffers, performing the
      // type conversions specified in the binding structures associated
      // with the accessor.
         pRowset->GetData(rghRows[irow], hAccessor, (void*) rgData);

         // Set currently read row as "current row."
         // Note: Other clients will choose different notions
         // of current row.
         If (pIRowPosition->ClearRowPosition () == S_OK)
            pIRowPosition->SetRowPosition (NULL, rghRows[irow],
            DBPOSITION_OK);

         // Convenience function to print the data
         PrintData(rgData);
      } 
   // Release the rows just printed from the rowset.
   PRowset->ReleaseRows(cRowsObtained, rghRows, NULL, NULL, NULL);
   }