序列化ADODataSet, ADOQuery

Posted 2020-11-22 zyb2016

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

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

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;