服务端直接将TADOQuery查询出来的数据直接转换成TStream自己进行传递,到客户端用一个TADOQuery对象还原流就可以了。
方法一<转载>
是将recordset保存成流接口->转成OleVariant ->写入流
class function TADOTools.saveToStream2( pvDataSet: TCustomADODataSet): TMemoryStream; var AStream:_Stream; V:OLEVariant; P:Pointer; begin AStream:=CoStream.Create; OLEVariant(pvDataSet.Recordset).Save(AStream, adPersistADTG); AStream.Position:=0; V:=AStream.Read(AStream.Size); result:=TMemoryStream.Create; try P:=VarArrayLock(V); try result.Size:=VarArrayHighBound(V,1)+1; Move(P^,result.Memory^, result.Size); finally VarArrayUnLock(V); end; except result.Free(); result := nil; raise; end; end;
class procedure TADOTools.loadFromStream2(pvDataSet: TCustomADODataSet; pvStream: TMemoryStream); var V:OLEVariant; AR:_Recordset; AStream:_Stream; P:Pointer; begin pvStream.Position:=0; OLEVariant(pvDataSet.Recordset).Open(TStreamAdapter.Create(pvStream) as IUnknown, adPersistADTG); AR.Open(AStream, EmptyParam,adOpenUnspecified, adLockUnspecified, -1); pvDataSet.Recordset:=ADOInt._Recordset(AR); V:=VarArrayCreate([0,pvStream.Size-1], varByte); P:=VarArrayLock(V); try Move(pvStream.Memory^, P^, pvStream.Size); finally VarArrayUnLock(V); end; AStream:=CoStream.Create; AStream.Open(EmptyParam,adModeUnknown,adOpenStreamUnspecified,‘‘,‘‘); AStream.Type_:=adTypeBinary; AStream.Write(V); AR:=_Recordset(CoRecordset.Create); AStream.Position:=0; AR.Open(AStream,EmptyParam,adOpenUnspecified, adLockUnspecified, -1); pvDataSet.Recordset:=ADOInt._Recordset(AR); end;
方法二:直接调用recordset保存成流借用TStreamAdapter
class procedure TADOTools.saveToStream(pvDataSet: TCustomADODataSet; pvStream:TStream); begin OLEVariant(pvDataSet.Recordset).Save(TStreamAdapter.Create(pvStream) as IUnknown, adPersistADTG); //adPersistXML end; class procedure TADOTools.loadFromStream(pvDataSet: TCustomADODataSet; pvStream: TStream); var AR:_Recordset; begin AR:=_Recordset(CoRecordset.Create); pvStream.Position:=0; AR.Open(TStreamAdapter.Create(pvStream) as IUnknown, EmptyParam,adOpenUnspecified, adLockUnspecified, -1); pvDataSet.Recordset:=ADOInt._Recordset(AR); end;
时间: 2024-11-05 12:07:06