Loading data to ListGrid

Hello,

i have question about loading data to ListGrid.
I try to load data in ListGrid as in your live table samle from xml and in works very fast.
But since i have data in my database i need to fill ListGrid without xml.
I tray to fill DataSource with ListGridRecord from an array, but loading data in ListGrid is very slow.

So is there any faster way and what is difference between xml data loading in DataSource and loading ListGridRecords in DataSource.

thank you for help