TreeView Gadget

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Treeview Gadgets can be loaded into a Form Section. They are data-bound tree grids that allow you to drill down through levels of hierarchical nodes.

Treeview gadget.png

You build Apps in Lianja App Builder visually using the Page Builder.

If you have not yet done so please read Understanding the Lianja Architecture and also Understanding ART to better understand this article.

An App consists of pages. Pages are made up of Sections. Form sections are made up of FormItems. We call these collectively "UI Elements" or "Visual Elements".

Setting Attributes Declaratively

You adjust the appearance and behavior of each UI Element in the Attributes Tab of the App Inspector.


The attributes available consist of some common ones as well as some specific to the UI Element being inspected.

Getting and Setting Attributes Programmatically

The setAttribute(name, value) method can be used to set the value of an Attribute:


Note: on the desktop, the shortened form setAttr(name,value) is also available.

The getAttribute(name) method can be used to get the value of an Attribute:

cTitle = Lianja.get("pageid.sectionid.fieldid").getAttribute("caption")

Note: on the desktop, the shortened form getAttr(name) is also available.

See Also

TreeView Options, TreeView Section Attributes

Demo Apps (included in the Lianja App Builder distribution):

  • TreeViewGadget App (example_treeviewgadget)



Attribute Description Name Type
Name The name for this gadget (unique to the section) id Character
Full name The full name for this gadget including its parent page and section, e.g. page1.section1.field1 fullid Character
Alias name The alias name for this gadget aliasid Character
App Doc The App Doc file for this gadget. This will be included in the App Doc when it is generated. appdoc Character
Tag The tag for this gadget tag Character
Meta types A comma separated list of metatype names metatypes Character
Type The type of control: Gadget (readonly) type Character
Gadget type The type of gadget: treeview (readonly) gadgetType Character
Margin Margin size around the gadget gadgetMargin Int
Fixed width Fixed gadget width in pixels gadgetFixedWidth Int
Fixed height Fixed gadget height in pixels gadgetFixedHeight Int
Inline Render the gadget inline rather than it its own column (True | False) gadgetInline Boolean
Stretch width Auto stretch the width of the gadget into the width of the section (True | False) gadgetStretchWidth Boolean


Attribute Description Name Type
Absolute Enable or disable absolute positioning (True | False) absolutePosition Boolean
Top Top position in pixels absolutePositionY Int
Left Left position in pixels absolutePositionX Int
Width Width in pixels absolutePositionWidth Int
Height Height in pixels absolutePositionHeight Int
CSS style CSS style (separate attributes with ; or use app:/filename.css) cssStyle Character


Attribute Description Name Type
Caption The caption for the gadget caption Character
Caption CSS style The gadget caption CSS style (separate attributes with ';' or use app:/filename.css or specify CSS classes separated by spaces). captionCSSstyle Character
Background color The background color for the caption backColor Character
Foreground color The foreground color for the caption foreColor Character
Font The font for the caption captionFont Character
Icon The image for the caption (png | jpg | gif).
Use app:/imagename.ext for app specific images.
captionIcon Character
Border width The caption border width captionBorderWidth Int
Border color The caption border color captionBorderColor Character
Transparency Specify a transparency percentage from 0 to 100 transparency Int
Gradient colors Render the caption color as a gradient (True | False) captionGradient Boolean
Gradient type Specify the gradient type captionGradientType Int
Gradient start color Gradient start color captionFromColor Character
Gradient end color Gradient end color captionToColor Character


Attribute Description Name Type
Tree items A list of items to display in the Tree, e.g.
Static list of choices:
Dynamic list of choices from a table:
Dynamic list of choices from a table (SQL SELECT):
select expression from tablename
choiceList Character
Columns to group by The number of columns to group by to form the tree hierarchy. When grouping data, use a SQL SELECT ORDER BY clause. treeGroupByColumns Int
Selection column The column to substitute into the Click/DblClick delegate. Use {} in the delegate where you want the text from this column to be placed. treeViewSelectionColumn Int
CSS style CSS style for the gadget (separate attributes with ; or use app:/filename.css) gadgetCssStyle Character
Column icons A comma separated list of column icons. treeColumnIcons Character
Hide column headers Hide the column headers (True | False) treeViewHideColumnHeaders Boolean
Header labels A comma separated list of header labels headerLabels Character
Column widths A comma separated list of column widths columnWidths Character
Column alignments A comma separated list of column alignments e.g. left,right,center columnAlignments Character
Alternating row colors Alternate row colors (True | False) treeViewAlternatingRowColors Boolean
Row height Row height for the Tree items treeViewRowHeight Int
Font size Font size for the Tree items treeViewFontSize Int
Expand all Expand all Tree items when first loaded (True | False) treeViewExpandAll Boolean
Expand depth Expand all Tree items when first loaded to this depth treeViewExpandDepth Int
Show indicators Show expand/collapse indicators in the tree (True | False) treeViewShowIndicators Boolean
Background color The background color for the gadget gadgetBackColor Character
Foreground color The foreground color for the gadget gadgetForeColor Character

Other Options

Attribute Description Name Type
Hide header Hide gadget header at runtime (True | False) gadgetHideHeader Boolean

Custom Delegates

Attribute Description Name Type
Init The delegate for the Init event initAction Character
Load The delegate for the Load event loadAction Character
Ready The delegate for the Ready event readyAction Character
Click The delegate for the item Clicked event ClickAction Character
Double Click The delegate for the item Double Clicked event dblClickAction Character

Permissions and Roles

Attribute Description Name Type
Read roles A comma separated list of roles that can read (and view) the data. permRead Character
Update roles A comma separated list of roles that can perform update operations on the data. permUpdate Character

UI Presentation Rules

Attribute Description Name Type
Desktop Include this gadget in a Desktop client (True | False). desktopUI Boolean
Web Include this gadget in a Web client (True | False). webUI Boolean
Tablet Include this gadget in a Tablet client (True | False). tabletUI Boolean
Phone Include this gadget in a Phone client (True | False). mobileUI Boolean
UI States UI states that affect this gadget. Specify multiple states as a comma separated list. state Character
Initial UI state The initial UI state for this gadget. uiStateInit Character
Readonly when Gadget is readonly at runtime if specified expression evaluates to true. readonlyWhen Character
Visible when Gadget is visible at runtime if specified expression evaluates to true. visibleWhen Character
Hidden at runtime Hide this formitem at runtime (True | False). hiddenAtRuntime Boolean
Display orientation Display depending on mobile device orientation for Tablets and Phones. (Always | Portrait | Landscape) displayOrientation Character
Apply rules on change Apply UI presentation rules (Visible when and Readonly when) when data is changed interactively or when navigating records (True | False). applyRulesOnChange Boolean