c# Actualization of datas in Datagridview while closing other window

I have a Form1 and inside a SplitContainer with Panel1 and inside Daragridview1, Panel2 a inside Datagridview2 filled with datas from DataTable
In Datagridview2 I select the row and push the button which opens Form2 with this DataTable rows fields values.
After editing those I push the button which closes the Form2 and update the DataTable.
Now my problem comes, I am not able to get to the point where the datas would be automaticly actualizated in Datagridview2 immidiatelly after closing the Form2.