>when i design a programm for processing science data , i draw a curve use these data on a form ,
> now i will print it into a .bmp file for save,final i will save it into general field.
>
>but i don't know how to save graph which draw in form
>into a .bmp file.
>could you tell me?

I don't know about the native abilities of the program you use to bring up a graph on form. In my imaging applications I use image OCX which allows me to save any part of screen/window to image file (BMP or something else) and store it in general field.