Try:
if (myDataGridView.Rows.Count > 0)
{
DataGridViewRow row = myDataGridView.Rows[myDataGridView.Rows.Count - 1];
...
}
"i am using data grid control not data grid view control..."
Then you need to use the CurrencyManager:
CurrencyManager cm = (CurrencyManager)this.BindingContext(myDataGrid.DataSource, myDataGrid.DataMember);
DataView dv = (DataView)cm.List;
DataRow dr = dv[cm.Position].Row;