>>I don' find any property in a Grid to tell me the number of all rows in a grid I can move up and down. Any idea?
>>
>>Thank's Zlatko.
>
>I don't know this property either, but you can calculate it: (grid.height-header height)/(rowheight+linesheight (don't know, how it called, you can neglect it, since it's small))

You forgot the height of the horizontal scrollbar that could be present.