private void item_PropertyChanged(object sender, PropertyChangedEventArgs e)
{
RaisePropertyChanged(e.PropertyName);
if (e.PropertyName == "Amount")
{
TotalAmount = MainRowList.Sum(x => x.Amount);
}
if (e.PropertyName == "Qty")
{
TotalQty = MainRowList.Sum(x => x.Qty);
}
}