Question

我有一个带有servermethod的datasnap服务器来加载流，我得到 jpeg错误＃53 ，我的目标是获取缩略图大小，我从BLOB fiel获取流，加载到Bitmap对象，然后创建缩略图并将该缩略图转换回流并发送到客户端

加载流后出错

我正在使用 XE7，MSSQL，VLC Datasnap Server

服务器端

function TDSServerMethods.GetImage(proid, Width, Height:   Integer;  out ImgStream: TStream): Boolean;
var
  Bitmap,Bitmap2: FMX.Graphics.TBitMap;
  scale: Single;
  T:TStream;
  stream: TStream;
 begin
  Result := False;
  ImgStream := nil;
  WITH SPPROC  do
   begin
           close;
           ProcedureName := 'XXXXXX';
           Parameters.Clear ;
           Parameters.CreateParameter('@ID',     ftInteger,pdInput, 0,proid );
           Open;
          Result := recordcount > 0;

   end;

    try

      T :=   SPPROC.CreateBlobStream(SPPROC.FieldByName('file'),TBlobStreamMode.bmRead);
      T.Seek( 0, TSeekOrigin.soBeginning );
      T.Position := 0;

       Bitmap := FMX.Graphics.TBitMap.Create;
       Bitmap.LoadFromStream( T   );

       scale := RectF(0, 0, Bitmap.Width, Bitmap.Height).Fit(RectF(0, 0, 200, 200));
       Bitmap2 :=  Bitmap.CreateThumbnail(Round(Bitmap.Width / scale), Round(Bitmap.Height / scale));

      stream := TMemoryStream.Create;

     stream.Position := 0;
     Bitmap2.SaveToStream(stream);
     stream.Seek( 0, TSeekOrigin.soBeginning );
     stream.Position := 0;

     ImgStream :=  stream

    except
      Exit(False);
    end;


end;

客户端

procedure TFrmMain.Button3Click(Sender: TObject);
var
   AImageStream: TStream;
   jp: TJPEGImage;

begin

    if ( DSServerMethods.GetImage(1038,0, 0, AImageStream))   then

            begin
               jp := TJPEGImage.Create;
               AImageStream.Position := 0;
               jp.LoadFromStream(     AImageStream   ); **here i got jpeg error #53**
               Image1.Picture.Assign( jp );

            end;

end;

此行中的

是错误 jpeg错误＃53 jp.LoadFromStream（AImageStream）;

但是，如果我使用这个服务器功能一切正常

   function TDSServerMethods.GetImage(proid, Width, Height:   Integer;  out ImgStream: TStream): Boolean;
    var
      Bitmap,Bitmap2: FMX.Graphics.TBitMap;
      scale: Single;
      T:TStream;
      stream: TStream;
     begin

      Result := False;
      ImgStream := nil;
      WITH SPPROC  do
       begin
               close;
               ProcedureName := 'XXXXXX';
               Parameters.Clear ;
               Parameters.CreateParameter('@ID',     ftInteger,pdInput, 0,proid );
               Open;
              Result := recordcount > 0;

       end;

        try

          ImgStream :=   SPPROC.CreateBlobStream(SPPROC.FieldByName('file'),TBlobStreamMode.bmRead);


        except
          Exit(False);
        end;

    end;

jpeg错误＃53从Datasnap加载流

0 个答案: