I have c# .net windows form application. I use class MyDataGridTextBoxColumn derived from class DataGridTextBoxColumn and add custom column style. I have overriden paint method of MyDataGridTextBoxColumn in which i change backbrush value. my application needs to work with large database records. For records more 100 thousand , if i scroll records with mouse then scrolling is fast enough but if i use page up / page down keys then it takes considerable time to scroll. why is this difference in speed of key up/down and mouse? if your windows application using datagrid has large number of records then what must be done to load data faster in display and scoll faster using mouse and page up/down keys.