Question Why datagridview very slow??Help me guys....

[voidcode]

I have a DataGridView (call FG)
my FG content is the import data from the excel file (. xls) amounted to 1469 rows count, then I have a code to give the value 'True' to the FG column(0) automatically:

For i As Integer = 0 To fg.Rows.Count - 1
fg.Item(0, i).Value = True '====>>> set value to checked
Next

This code successfully,
but running very slow .... about 2-3 minutes ....
anyone have an answer?

thanks for your help...

sorry if my english is bad..