Treeview Control

A TreeView control displays items in a hierarchical display. Each item, called a node, may contain parent or child items, and may be expanded or collapsed via a mouse click.

Client support

Newlook Smartclient only.

Use

This control is useful for displaying data which is hierarchical in nature. It allows users to expand only the information that they need to see. Tree view nodes can also be displayed with check boxes which makes it possible to programmatically select or clear nodes by setting the Node's Checked property to true or false.

After inserting a tree view control in Designer, you can add, remove or reorganize Node objects by setting the relevant properties in Designer or invoking the relevant methods via a script.

The key property of the TreeView control is the Nodes property. It contains an array of nodes for the control. Icons can be displayed next to nodes by associating an image list control with the tree view's Icons property. Specific icons can then be assigned to individual nodes via the Icon and SelectedIcon property.

At runtime it is possible to return the node that the user has clicked via the LastClickedNode property.

Material skin considerations

When the material skin is enabled in your solution, tree view controls will be rendered with material styling. The most noticeable difference is a cleaner appearance, no borders and more spacing within the tree. If you have checkboxes enabled, then they will be rendered with the material primary color in the selected state.

Material skin

Classic skin

ClosedCommon TreeView Tasks
Inserting a TreeView control
  1. Open the relevant screen in Designer () mode.
  2. Select Insert|TreeView () from the main menu, then use your cursor to draw the graphic area on the screen.
  3. Set any relevant properties for the tree view in the Properties pane.
Inserting Nodes manually in Designer
  1. Select the tree view control in Designer.
  2. In the Properties pane, click the prompt button next to the Nodes property to open the TreeView Editor window.
  3. Click the Add button .
  4. In the property editor, update the text property to specify the display text for the node.
  5. Add as many Nodes as necessary. Use the Add button if you wish to create a node at the same level as the selected node. Use the Add Child button if you wish to create a node below the currently selected node.
  6. For each node that is created, Newlook creates an associated Node object which is added to the Nodes collection.
  7. If required, select each node object and change any relevant properties i.e. icon, Backcolor, ForeColor etc. For more information on available node properties refer to the properties section of the Node object reference topic.
  8. To rearrange the order of nodes within a level use the repositioning buttons.
  9. Click OK to close the TreeView Editor.
Inserting Nodes dynamically at runtime

Nodes can be added to a tree view control's Nodes collection via the Add method. To remove all nodes from a TreeView use the Clear method, to remove individual nodes use the Remove method.

Returning the clicked node at runtime

The LastClickedNode property can be used within a script or macro to return the node that was last clicked, or any property of that node. ()

ClosedProperties

Newlook Smartclient | Newlook Server | Deprecated | Obsolete

Property

Client

Description

AllowDrop

Gets or sets whether the object allows drag/drop support. Newlook Smartclient-only property.

BackColor

Gets or sets the background color of the object.

BorderStyle

Gets or sets the style of a control's border.

CCSID

Gets or sets the Coded Character Set Identifier (CCSID), which defines the control's code page and character set.

CheckBoxes

Gets or sets whether a check box is displayed next to each item.

Column

The green screen column coordinate that marks the beginning of the object. Read only. Host generated controls only.

DroppedFiles

Returns a collection of files dropped onto the object.

Enabled

Gets or sets the enabled state of the object.

FontBold

Gets or sets whether text should be shown in a bold font.

FontItalic

Gets or sets whether text should be shown with an italic style.

FontName

Gets or sets the name of the font family used to display text.

FontSize

Gets or sets the font point size used to display text.

FontUnderline

Gets or sets whether text should be diplayed underlined.

ForeColor

Gets or sets the foreground (text) color of the control.

FormControlsCollectionIndex

Sets or returns the current control index for an object.

Height

Returns or sets the height of the object's size in pixels at default size, which is the object's size at design-time.

HideSelection

Gets or sets a value that determines whether the selected node or list view item remains selected when the control loses focus. Deprecated property. Obsolete

HotTracking

Gets or sets a value which enables mouse hot-tracking on collection items.

Icons

Gets or sets the name of the ImageList control which provides the images associated with this control. Smartclient-only.

LabelEdit

Gets or sets whether the user can edit label items. Design-time only. Not available at run-time.

LastClickedNode

Returns the node that was last clicked by the user. Read-only, runtime property.

LastItemClicked

Returns the key of the last node clicked. Read-only, runtime property. Obsolete

Left

Determines the distance, in pixels, between the left edge of the control and the left edge of its form or parent container at default size, which is the object's size at design-time.

LineStyle

Gets or sets the style of lines displayed between nodes in the tree view control. Deprecated property. Obsolete

Name

Gets or sets the name of this object.

Nodes

Gets the collection of root-level node objects.

OnAfterLabelEdit

Gets or sets the macro or script to be run when the AfterLabelEdit event occurs.

OnBeforeLabelEdit

Gets or sets the macro or script to be run when the BeforeLabelEdit event occurs.

OnClick

Gets or sets the name of the macro or script to be run when the Click event is triggered.

OnCollapse

Gets or sets the macro or script to be run when the Collapse event occurs.

OnDrop

Gets or sets the name of a macro or script to be run when the Drop event occurs. Newlook Smartclient-only property.

OnExpand

Gets or sets the macro or script to be run when the Expand event occurs.

OnGotFocus

Gets or sets the name of the macro or script to be run when the GotFocus event is triggered. Smartclient-only property.

OnLostFocus

Gets or sets the name of the macro or script to be run when the LostFocus event is triggered. Smartclient-only property.

OnNodeCheck

Gets or sets the macro or script to be run when the NodeCheck event occurs.

OnNodeClick

Gets or sets the macro or script to be run when the NodeClick event occurs.

OnNodeDoubleClick

Gets or sets the macro or script to be run when the NodeDoubleClick event occurs.

Row

The green screen row coordinate that marks the beginning of the object. Read only. Host generated controls only.

StateIcons

Gets or sets the name of the ImageList control which provides images used when the CheckBoxes property is turned on. Depreacted property. Obsolete

Style

Gets or sets the visual style for the tree view. Deprecated property. Obsolete

TabIndex

Gets or sets a value which determines the control's tab order.

TabStop

Gets or sets whether the Tab key can be used to set focus to the control.

Tag

Gets or sets user defined information for the control.

ToolTipText

Gets or sets the control's tool-tip text.

Top

Determines the distance, in pixels, between the top edge of the control and the top edge of its form or parent container at default size, which is the object's size at design-time.

Type

Returns a value which specifies the control's type. Read only.

Variable

Gets or sets the name of the variable that stays synchronized with the contents of the control. Obsolete

Visible

Gets or sets whether the control, object or form is visible or hidden.

Width

Gets or sets the width of the object in pixels at default size, which is the object's size at design-time.

ClosedMethods

Newlook Smartclient | Newlook Server | Deprecated | Obsolete

Property

Client

Description

EnsureVisible

Ensures that the specified node is visible within the control, scrolling the tree view control if necessary.

GetFirstVisible

Returns the first visible item in the control.

See Also

Node object | Nodes collection | ListView control

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