如何显示和取出stream变量中BMP、JPG的图象？

Question

一个stream变量包含BMP或者JPG图象内容，怎样才能将其显示在Timage图片控件中，最后又怎样将Timage控件的图象内容存到一个Tstream变量？注意：这个stream内容事先并不能确定为BMP还是JPG！我是想做成一个activeX Form，以供其它软件使用，就卡在此处，请各位高手指教！给出成功的方法的，肯定给分！

Answer 1

try先按bmp处理,如果except 再按jpeg处理。
var strm:TMemoryStream;
    jpg:TJpegImage;
begin
  if OpenDialog1.Execute then
  begin
    strm:=TMemoryStream.Create;
    try
      strm.LoadFromFile(OpenDialog1.FileName);
      try
        Image1.Picture.Bitmap.LoadFromStream(strm);
      except
        try
          strm.Position:=0;
          jpg:=TJPEGImage.Create;
          jpg.LoadFromStream(strm);
          Image1.Picture.Assign(jpg);
        except
        end;
      end;
    finally
      FreeAndNil(strm);
      FreeAndNil(Jpg);
    end;
  end;
end;
最好有个变量保存当前stream是bmp还是jpg

Answer 2

哦，错了一下
var strm:TMemoryStream;
    jpg:TJpegImage;
begin
  if OpenDialog1.Execute then
  begin
    strm:=TMemoryStream.Create;
    try
      strm.LoadFromFile(OpenDialog1.FileName);
      try
        Image1.Picture.Bitmap.LoadFromStream(strm);
      except
        try
          strm.Position:=0;
          jpg:=TJPEGImage.Create;
          jpg.LoadFromStream(strm);
          Image1.Picture.Assign(jpg);
        finally
          FreeAndNil(Jpg);//free改在这里
        end;
      end;
    finally
      FreeAndNil(strm);
    end;
  end;
end;

Answer 3

procedure TeditionForm.Button1Click(Sender: TObject);
var
  myjpg:Tjpegimage;
  mystream:Tmemorystream;
begin
  try
     if opendialog1.Execute then
     begin
        myjpg:=Tjpegimage.Create;
        try
           image1.Picture.LoadFromFile(opendialog1.FileName);
           myjpg.Assign(image1.Picture.Graphic);
           mystream:=Tmemorystream.Create;
           myjpg.SaveToStream(mystream);
           mystream.Position:=0;           datform.Qedition.Close;
           datform.Qedition.SQL.Clear;
           datform.Qedition.SQL.Add('select * from edition where e_id='+quotedstr(inttostr(e_id))+' order by e_id');
           datform.Qedition.Open;
           datform.Qedition.Edit;           tblobfield(datform.Qedition.FieldByName('e_img')).LoadFromStream(mystream);
           datform.Qedition.Post;           showmessage('录入成功!');
           myjpg.Free;
        except
           myjpg.Free;
           showmessage('录入失败!');
           exit;
        end;
     end;
  except
       myjpg.Free;
       showmessage('图相录入失败!');
       exit;
  end;
end;

Answer 4

procedure TeditionForm.DBGrid1CellClick(Column: TColumn);
var
  myjpg:Tjpegimage;
  mystream:Tmemorystream;
begin
  try
     label55.Caption:='你现在查看的款号是:'+datform.Qedition.FieldValues['e_office'];
     myjpg:=Tjpegimage.Create;
     mystream:=Tmemorystream.Create;     tblobfield(datform.Qedition.FieldByName('e_img')).SaveToStream(mystream);
     mystream.Position:=0;
     myjpg.LoadFromStream(mystream);
     image2.Picture.Assign(myjpg);     clipboard.Assign(myjpg);
     myjpg.Free;
  except
     showmessage('图相出错');
     myjpg.Free;
     exit;
  end;