数据库的OLE字段写入长二进制文件

//'***************************************************************************************

//'函数：将数据库的OLE字段写入长二进制文件

//'***************************************************************************************

//bool THsPart_clsPartCommonDB::PrintFieldToFile(TheFiled As ADODB.Field, ByVal strSaveName As String, _

// Optional IsAppend As Boolean)

bool THsPart_clsPartEntityDB::PrintFieldToFile(_RecordsetPtr &myRcdPtr,_variant_t index ,CString strSaveName /*ADODB.Fields TheFiled, CString strSaveName ,*Optional IsAppend As Boolean*/)

{

    //Dim MyRc As Recordset;

 VARIANT varBLOB;

 CFile myfile;

 bool bReturn = false;

    try

 {

   

 

  //'定义各种参数

  const int conChunkSize = 16384;

  int Chunks ;

  byte *Chunk = NULL; //Chunk() As Byte,

  //int FileNumber;

  long FragMent ,lngTotalSize;

  // 定义各种参数

  myfile.Open(strSaveName,CFile::modeCreate|CFile::modeReadWrite|CFile::typeBinary);

  /*FileNumber = FreeFile;

  Open strSaveName For Binary Access Write As #FileNumber;*/

 

  //将字段内的长二进制文件导出的文件

  lngTotalSize = myRcdPtr->Fields->GetItem(index)->ActualSize; //lngTotalSize = TheFiled.ActualSize;

  Chunks = lngTotalSize /conChunkSize;

  FragMent = lngTotalSize % conChunkSize;

  Chunk = (byte *)GlobalAlloc(GMEM_FIXED,FragMent); //ReDim Chunk(FragMent);

  varBLOB= myRcdPtr->Fields->GetItem(index)->GetChunk(FragMent); //Chunk() = TheFiled.GetChunk(FragMent);

  SafeArrayAccessData(varBLOB.parray,(void **)&Chunk);

  LPSTR buffer = (LPSTR)GlobalLock((HGLOBAL)Chunk);

  myfile.Write(buffer,FragMent);

  GlobalUnlock((HGLOBAL)Chunk);

  SafeArrayUnaccessData (varBLOB.parray);

  int counter;

  Chunk = (byte *)GlobalAlloc(GMEM_FIXED,conChunkSize);

  for(counter=1;counter<= Chunks;counter++) //For counter = 1 To Chunks

  {

   //Chunk() = TheFiled.GetChunk(conChunkSize);

   varBLOB= myRcdPtr->Fields->GetItem(index)->GetChunk(conChunkSize);

   SafeArrayAccessData(varBLOB.parray,(void **)&Chunk);

   buffer = (LPSTR)GlobalLock((HGLOBAL)Chunk);

   myfile.Write(Chunk,FragMent);

   SafeArrayUnaccessData (varBLOB.parray);

  }

  GlobalUnlock((HGLOBAL)Chunk);

  Chunk = NULL;

  buffer = NULL;

  ////////////////////////////////////////////////

 

  ////////////////////////////

 

  //////////

  //Close #FileNumber

  myfile.Close();

 

  bReturn = true;

  return bReturn;

 }

 catch(...)

 {

 

  AfxMessageBox(_T("PrintFieldToFile wrong!"));

  //Close #FileNumber;

  myfile.Close();

 }

 return bReturn;

}