Hierarchies defined in the context can be visualized using the Tree UI element. The hierarchy to be displayed is defined in the context. You can describe this context structure in two ways:
● If the number of levels is not known at design time, a recursive node is used.
● If the number of levels is already specified at design time, a recursive node is not used.
The following graphic shows how the UI element is displayed:
The Tree UI element is bound against the top-level context node to be displayed.
You use nodes (TreeNodeType elements) or leaves (TreeItemType-Elemente) to specify which subnodes are to be displayed and which context atttributes are to be displayed on these subnodes as a text or tooltip. The dataSource property of the TreeNodeTypeelement or TreeItemType element is bound to the corresponding context node and the properties text, tooltip, and so on, are bound to the corresponding context attributes on this context node.
TreeItemType elements cannot have children. Therefore, they are always displayed as leaves. They are used when it is decided at design time that the corresponding node does not have children. When using TreeNodeType elements, the decision of whether to use children is dynamically made at runtime.
Hierarchy levels defined in the context cannot be left out when displaying the UI element. For example, a TreeNodeType element that is bound to the Orders must also exist to display the items for the hierarchy Customers → Orders → Items, which is defined in a context.
All nodes that are not directly below the context root node must be non-singleton nodes, because all elements should be displayed in a tree regardless of the lead selection.
● dataSource
This property is used to specify the data source. You can use it to specify the path to the context node providing the data.
● defaultItemIconAlt
This property is deprecated. Use tooltip instead.
● defaultItemIconSource
defines the path to the icon source of the graphic to be displayed for a leave.
More information: Specifying the Image Source
● defaultNodeIconAlt
This property is deprecated. Use tooltip instead.
● defaultNodeIconSource
defines the path to the icon source of the graphic to be displayed for a node.
More Inforamtion: Specifying the Image Source
● minHeight
Specifies the minimum height of the tree.
● rootText
Describes the text for labeling the root node.
● rootVisible
Specifies whether the root node of the tree structure is visible.
● selectionChangeBehaviour
The selectionChangeBehaviour property can be filled with the following values and is represented by the enumeration type WDLeadSelectionChangeBehaviour.
auto |
Specifies that the UI element automatically changes the lead selection after an interaction by the user before the corresponding event is triggered. |
manual |
Specifies that the UI element does not change the lead selection after an interaction by the user but triggers the corresponding event. In this case, the event handler must change the lead selection to enable the UI element to display the data. This setting allows you to check the change of the lead selection. |
● title
Describes the tree header.
● titleVisible
Specifies whether the tree label is visible.
● width
Specifies the width of the tree and can be specified in CSS units like em, ex, pixels, or percentage.
Name |
Interface |
Type |
Initial Value |
Bindable |
dataSource |
IWDTree |
Object |
|
bindable_mandatory |
defaultItemIconAlt |
IWDTree |
String (TranslatableText) |
|
bindable |
defaultItemIconSource |
IWDTree |
String |
|
bindable |
defaultNodeIconAlt |
IWDTree |
String (TranslatableText) |
|
bindable |
defaultNodeIconSource |
IWDTree |
String |
|
bindable |
enabled |
IWDUIElement |
boolean |
true |
bindable |
minHeight |
IWDTree |
String (CSS size) |
|
bindable |
rootText |
IWDTree |
String (TranslatableText) |
|
bindable |
rootVisible |
IWDTree |
boolean |
true |
bindable |
selectionChangeBehaviour |
IWDTree |
WDLeadSelectionChangeBehaviour |
auto |
not_bindable |
title |
IWDTree |
String (TranslatableText) |
|
bindable |
titleVisible |
IWDTree |
WDVisibility |
visible |
bindable |
tooltip |
IWDUIElement |
String (TranslatableText) |
|
bindable |
visible |
IWDUIElement |
WDVisibililty |
visible |
bindable |
width |
IWDTree |
String (CSS size) |
|
bindable |
The tooltip property is ignored and does not affect the browser.
● onDrop(String data, String mimeType, int offset, String path, String tags)
This event is triggered if the user drops something on the tree's root node, which must be a valid drop target for that drag-and-drop operation. Note that the event is fired on the same view element which aggregates the drop target info which governs the behavior of that drop. In other words, the event is fired on the tree itself, no matter whether one attempts to drop something right onto the tree's root node or in between existing direct children of it.
The parameters are:
○ data: The data specified for the drag source.
○ mimeType: the mime type specified for the drag source.
○ offset: the position relative to the index, the user has dropped the object onto.
■ -1: just above the item specified by the index
■ 0: right onto the item specified by the index
■ +1: just below the item specified by the index.
○ path: The tree node is described by a path to the node element representing it. Declare an action and event handler parameter of type IWDNodeElement (or one of your own node element classes) along with a suitable parameter mapping; then the path will be automatically transformed into a node element instance.
○ tags: the tags defined for the drag source
More information: Implementing Drag and Drop