How to show the cardview in multiband grid.. parent\child\grandchild
This won't work, because a band that shows in Card View will not show any child rows. You could do this in any band that doesn't have children, however. Or, instead, you can use Row Layouts to get a similar look-and-feel while preserving the capability of showing child rows.
foreach (UltraGridBand band in winGrid.DisplayLayout.Bands) {
band.CardView = true;
// set any card settings here using band.CardSettings
}