Displaying Child Items
By default, the children of a menu item are displayed when the user hovers the mouse over the parent item.When the mouse moves over a new parent item, the original submenu collapses and the children of the new parent menu item are displayed. The ExpandDelay and CollapseDelay properties specify the time, in milliseconds, after the mouse enters or exits a parent item until the list of child items begins to expand or collapse.
You can use the ClickToOpen property to specify that menu items do not expand when the mouse hovers over them until the user clicks the menu with the mouse. When ClickToOpen is True, the menu does not expand until the user clicks on a root item, at which point the root item expands. Once clicked, the menu expands and collapses as normal, until the user clicks again (either on a menu item or outside the menu). The ExpandDelay property controls the time, in milliseconds, after the user first clicks the menu until the menu item expands. The CollapseDelay property controls the time, in milliseconds, after the user clicks a second time until the menu items all collapse.
You can further customize the behavior of the menu when it expands and collapses using animations.
As of Q3 2009, RadMenu supports multi-column rendering of child items. This feature is controlled through the GroupSettings (either DefaultGroupSettings or per-item GroupSettings) using two properties:
The RepeatDirection property determines the order in which the items are rendered.If this property is set to RepeatDirection.Vertical, the items are displayed in columns loaded from top to bottom, then left to right, until all items are rendered. If this property is set to RepeatDirection.Horizontal, the items are displayed in rows loaded from left to right, then top to bottom, until all items are rendered. The RepeatDirection has no effect if RepeatColumns is set to 1 (default).
The RepeatColumns property specifies the number of columns.
Note: Scrolling is disabled if multi-column rendering is in effect.