Implement show-hide (expand/collapse) on a tree diagram

Applies to: Nevron Diagram for .NET

How to implement show-hide (expand/collapse) on a tree diagram?

The following code example will generate a random tree diagram with show-hide subtree decorator for each shape that has children:

using Nevron.GraphicsCore;
using Nevron.Diagram;
using Nevron.Diagram.Shapes;
using Nevron.Diagram.WinForm;
using Nevron.Diagram.Templates;
using Nevron.Diagram.Filters;
using Nevron.Diagram.Layout;
using Nevron.Diagram.DataStructures;
view.Dock = DockStyle.Fill;
view.ViewLayout = ViewLayout.Fit;
view.Grid.Visible = false;
view.GlobalVisibility.ShowPorts = false;
// create a random tree
NGenericTreeTemplate treeTemplate = new NGenericTreeTemplate();
treeTemplate.BranchNodes = 3;
treeTemplate.VerticesSize = new NSizeF(50, 50);
treeTemplate.Balanced = false;
treeTemplate.Levels = 5;
// add show-hide subtree decorator for each shape that has children
foreach (NShape shape in document.ActiveLayer.Children(NFilters.Shape2D))
    if (shape.GetOutgoingShapes().Count == 0)
    // create the decorators collection
    NShowHideSubtreeDecorator decorator = new NShowHideSubtreeDecorator();
    decorator.Offset = new NSizeF(-11, 11);
    decorator.Size = new NSizeF(15, 15);
    decorator.Alignment = new NContentAlignment(ContentAlignment.TopLeft);
document.AutoBoundsMinSize = new NSizeF(400, 400);
// layout with a layered tree layout
NLayoutContext context = new NLayoutContext();
context.GraphAdapter = new NShapeGraphAdapter(true);
context.BodyAdapter = new NShapeBodyAdapter(document);
context.BodyContainerAdapter = new NDrawingBodyContainerAdapter(document);
NLayeredTreeLayout layout = new NLayeredTreeLayout();
layout.VertexSpacing = 50;
layout.LayerSpacing = 50;
layout.Layout(document.ActiveLayer.Children(null), context);
// size to visible shapes
document.SizeToContent(document.AutoBoundsMinSize, document.AutoBoundsPadding, NFilters.Visible);

Imports Nevron.GraphicsCore
Imports Nevron.Diagram
Imports Nevron.Diagram.Shapes
Imports Nevron.Diagram.WinForm
Imports Nevron.Diagram.Templates
Imports Nevron.Diagram.Filters
Imports Nevron.Diagram.Layout
Imports Nevron.Diagram.DataStructures
view.Dock = DockStyle.Fill
view.ViewLayout = ViewLayout.Fit
view.Grid.Visible = False
view.GlobalVisibility.ShowPorts = False
' create a random tree
Dim treeTemplate As New NGenericTreeTemplate()
treeTemplate.BranchNodes = 3
treeTemplate.VerticesSize = New NSizeF(50, 50)
treeTemplate.Balanced = False
treeTemplate.Levels = 5
' add show-hide subtree decorator for each shape that has children
For Each shape As NShape In document.ActiveLayer.Children(NFilters.Shape2D)
    If shape.GetOutgoingShapes().Count = 0 Then
        Continue For
    End If
    ' create the decorators collection
    Dim decorator As New NShowHideSubtreeDecorator()
    decorator.Offset = New NSizeF(-11, 11)
    decorator.Size = New NSizeF(15, 15)
    decorator.Alignment = New NContentAlignment(ContentAlignment.TopLeft)
document.AutoBoundsMinSize = New NSizeF(400, 400)
' layout with a layered tree layout
Dim context As New NLayoutContext()
context.GraphAdapter = New NShapeGraphAdapter(True)
context.BodyAdapter = New NShapeBodyAdapter(document)
context.BodyContainerAdapter = New NDrawingBodyContainerAdapter(document)
Dim layout As New NLayeredTreeLayout()
layout.VertexSpacing = 50
layout.LayerSpacing = 50
layout.Layout(document.ActiveLayer.Children(Nothing), context)
' size to visible shapes
document.SizeToContent(document.AutoBoundsMinSize, document.AutoBoundsPadding, NFilters.Visible)

For more detailed information about Decorators, take a look at the Help Documentation:
Diagram for .NET > User's Guide > Document Object Model > Models > Shapes > Decorators

Related examples:
Diagram Windows Forms: Document Object Model - Shapes - Decorators folder
Diagram Web Forms: Show/Hide Subtree Decorator

Article ID: 99, Created On: 10/21/2010, Modified: 12/29/2010