Scroll Modes Basics
The TreeList provides options for rendering its content in a scrollable or non-scrollable mode. To configure the desired scroll mode, use the scrollable property.
You can also enable the virtual scroll mode of the TreeList by setting scrollable to virtual. For more information, refer to the article on virtual scrolling.
Scrollable Mode
When scrolling is enabled, the content of the TreeList is rendered as tables—one for the header area, another one for the scrollable data area, and a third one for the footer area. This behavior ensures that the header and footer areas of the TreeList are always visible while the user scrolls vertically.
Getting Started
The scrollable mode of the TreeList is enabled by default. You can configure the scrollable behavior through the scrollable option.
By default, the TreeList is as high as its content and as wide as the available space. To configure the height of the TreeList, either set its height input or use the style HTML property. To configure the width of the TreeList, use the style HTML property. If the height or width of the TreeList content exceeds the height or width of the TreeList itself, the TreeList renders a vertical or horizontal scrollbar respectively.
To enable horizontal scrolling, set the width of all columns.
Endless Scrolling
After the user scrolls to the end of the page, the TreeList enables you to load more records by appending additional pages of data on demand. To set the endless scrolling feature, use the scrollBottom event of the TreeList.
The following example demonstrates how to implement endless scrolling with local data.
Conditional Scrolling
By configuring the style.maxHeight property, you can set the TreeList in scrollable mode only when its rendered content exceeds certain height limits. If the content does not exceed the set maximum height, the height of the TreeList will be the same as the height of its content.
Scrolling To a Specific Row and Column
The TreeList allows you to scroll to a specific row or column by using the built-in scrollTo() method. The method accepts as an argument an object of type ScrollRequest that allows you to specify the zero-based row and column index of the record to which the component should scroll.
The following example demonstrates the behavior of the built-in scrollTo() method inside a TreeList with paging enabled.
Consider the following specifics when programmatically scrolling the TreeList:
- When the TreeList has virtualization enabled and the provided index or item is not visible in the current view, the
scrollTo()method will scroll the component to the position of the specified index or item. This operation will trigger thepageChangeordataStateChangeevent. - When the TreeList uses paging and the provided index is not available on the current page, the component will not be scrolled and the scroll position will not change.
- When the grouping feature is enabled, the
scrollTo()method will scroll to the provided index or item regardless of the type of the row. The specifics about paging and virtual scrolling still apply.
Non-Scrollable Mode
When the non-scrollable mode is enabled, the TreeList renders its data as a single table and the scrollbar is not displayed. To define a non-scrollable TreeList, set scrollable to none.