Repainting in a Windows Application

i have used two methods in windows application namely for event paint method name is Graph_Paint() and other event is for load Graphs_Load() and i am using scroll bars for that window when i drag the scroll bar it is repainting again and calling the method Graph_Paint() unable to see the correct picture of the graph.

alt text http://www.freeim开发者_StackOverflow社区agehosting.net/uploads/502ac0b588.jpg

the first URL image is the original one when i drag the scroll bar the image getting changed to second URL

alt text http://www.freeimagehosting.net/uploads/4c53ab4b2b.jpg

You need to clear the screen before you paint the repositioned graph.