void SizeChanged(object sender, ItemSizeChangedEventArgs e)
{
RaisePropertyChanged("Size");
if (Size.DisplaySize != FileSystemItemSize.Calculating)
{
UpdateAffectsTotalSize();
}
}
void TotalSize_SizeChanged(object sender, ItemSizeChangedEventArgs e)
{
TotalSize = new FileSystemItemSize(e.Size.NumSize);
}