请问：TDrawGrid的Canvas属性能否保存为图象?(30分)

TDrawGrid的Canvas属性能否保存为图象，比如，我用
DrawGrid1.Canvas.MoveTo(0,0);
DrawGrid1.Canvas.LineTo(Drawgrid2.Width,Drawgrid2.Height);
画了条直线，现在想将DrawGrid1保存为bmp图象，请问如何实现？
我用
bmp := TBitmap.Create;
bmp.Canvas.CopyRect(DrawGrid2.ClientRect,DrawGrid2.Canvas,DrawGrid2.ClientRect);
try
with bmp do
begin
SaveToFile('c:/111.bmp');
end;
finally
bmp.Free;
end;
好象不能实现。

有人告诉我错在什么地方吗？

试过了,不行

bmp的宽度和长度没有指定

bmp := TBitmap.Create;
bmp.Canvas.assign(DrawGrid2.Canvas);
try
with bmp do
begin
SaveToFile('c:/111.bmp');
end;
finally
bmp.Free;
end;