variant 和 Stream 的互換

在Com, Dcom, Com+中經常要用到variant, 而在delphi 中的文件操作之類中, 更多的用到Stream, 有時, 需要適當的互換!

Variant --> Stream

var ov: OleVariant;

ms: TStream; p: Pointer;

begin

ov := dmMain.ComConnection.AppServer.TimeZone;

ms := TMemoryStream.Create;

ms.Position := 0;

p := VarArrayLock(ov);

ms.Write(p^, VarArrayHighBound(ov, 1)); //這句可否改進?

VarArrayUnlock(ov);

ms.Position := 0;

...

ms.Free;

end;

Stream --> Variant

function TTCanteenSvr.Get_TimeZone: OleVariant;

var

AStream: TStream;

MyBuffer: Pointer;

begin

try

AStream := TFileStream.Create(, fmOpenRead);

Result := VarArrayCreate([0, AStream.Size - 1], VarByte);

MyBuffer := VarArrayLock(Result);

AStream.ReadBuffer(MyBuffer^, AStream.Size);

VarArrayUnlock(Result);

finally

AStream.Free;

end;