Delphi中variant 和 Stream 的互換

DELPHI中使用COM,COM+时候经常需要用到STREAM和VARIANT类型的转换

 

 1 procedure VarToStream(var AStm: TStream; var AOvar: Olevariant);
 2 var
 3     p: Pointer;
 4 begin
 5     AStm:= TMemoryStream.Create;
 6     AStm.Position := 0;
 7     p := VarArrayLock(AOvar);
 8     AStm.Write(p^, VarArrayHighBound(AOvar, 1));
 9     VarArrayUnlock(AOvar);
10 end;
11 
12 procedure StreamToVar(var AStm: TStream; var AOvar: Olevariant);
13 var
14     p: Pointer;
15 begin
16   AOvar := VarArrayCreate([0, AStm.Size - 1], VarByte);
17   p := VarArrayLock(AOvar);
18   AStm.ReadBuffer(p^, AStm.Size);
19   VarArrayUnlock(AOvar);
20 end;