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The TTree component is the central visual control in TeeTree. It maintains a network-hierarchy of nodes, similar to Microsoft’s TreeView control, but with significantly more power and flexibility.

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Overview

TTree is a visual component that manages a collection of nodes and their relationships. Unlike traditional tree controls, every node in TeeTree is a full standalone component with its own properties, methods, and events. 
// Creating a basic tree
var
  Tree: TTree;
begin
  Tree := TTree.Create(Self);
  Tree.Parent := Self;
end;

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Key Features

Node Management

Maintains a network-hierarchy of nodes with parent-child relationships

Visual Connections

Links nodes using connection components with customizable styles

Auto-Positioning

Automatic layout management through child manager classes

Rich Formatting

Full control over colors, borders, fonts, gradients, and more

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Component Architecture

TeeTree follows a component-based architecture where the Tree acts as a container: 
TCustomTree (Base Class)
  ├── TCustomTreeElement (Base for nodes and connections)
  │   ├── TTreeNodeShape (Individual nodes)
  │   └── TTreeConnection (Links between nodes)
  └── Child Managers (Layout algorithms)
The TCustomTree class is the base class, while TTree is the published component you’ll typically use in your applications.

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Global Configuration

TeeTree provides several global variables for fine-tuning behavior:
var
  TeeTreeAnimatedScroll  : Boolean = True;
  TeeLineClickTolerance  : Integer = 3;
  TeeConnectionCursor    : TCursor = crHandPoint;
  TreeListCapacity       : Integer = 100;
These global variables might be removed or replaced in future versions. Use with caution.
Adjust list capacities for better performance:
// Minimize memory usage
TreeListCapacity := 0;
TreeShapeListCapacity := 0;

// Optimize for large trees (1000+ nodes)
TreeListCapacity := 1000;
TreeShapeListCapacity := 1000;

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Working with Roots

The Tree maintains a collection of root nodes (nodes without parents): 
// Add root nodes
var
  RootNode: TTreeNodeShape;
begin
  RootNode := Tree.Shapes.Add('Root 1');
  RootNode.X0 := 10;
  RootNode.Y0 := 10;
end;

// Access all root nodes
for i := 0 to Tree.Roots.Count - 1 do
  ShowMessage(Tree.Roots[i].SimpleText);
Root nodes are automatically positioned based on the Tree’s GlobalFormat.ChildManager when their AutoPosition property is enabled.

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Layout Management

The Tree’s layout is controlled by the GlobalFormat.ChildManager object: 
// Use Explorer-style layout (default)
Tree.GlobalFormat.ChildManager := TTreeExplorerAlignChild.Create;

// Use circular layout
Tree.GlobalFormat.ChildManager := TTreeCircularAlignChild.Create;

// Use top-to-bottom layout
Tree.GlobalFormat.ChildManager := TTreeTopBottomAlignChild.Create;
Child managers determine how parent and children nodes are arranged on screen when nodes are auto-positioned. See Child Managers for details.

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Selection Management

TTree provides a built-in selection system: 
// Select a node
Tree.Selected.Add(MyNode);

// Select multiple nodes
Tree.Selected.ShiftState := [ssShift];  // Enable multi-select

// Access selected nodes
for i := 0 to Tree.Selected.Count - 1 do
  ProcessNode(Tree.Selected[i]);

// Clear selection
Tree.Selected.Clear;

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CrossBox (Expand/Collapse)

The CrossBox is the visual indicator (+/-) for expanding and collapsing nodes: 
// Configure CrossBox appearance
with Tree.CrossBox do
begin
  Size := 15;
  Style := cbsSquare;     // Square, Diamond, or Circle
  SignStyle := cssCross;  // Cross or Triangle
  Border.Color := clGray;
  Brush.Color := clWhite;
end;

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VCL vs FireMonkey

TeeTree supports both VCL and FireMonkey frameworks:
  • VCL: Uses TeeTree.pas unit
  • FireMonkey: Uses FMXTee.Tree.pas unit
The API is consistent across both frameworks, with minor platform-specific differences in rendering and events.

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Common Patterns

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Creating a Simple Hierarchy

var
  Root, Child1, Child2: TTreeNodeShape;
begin
  Root := Tree.Shapes.Add('Root');
  Child1 := Root.AddChild('Child 1');
  Child2 := Root.AddChild('Child 2');
  
  Root.Expanded := True;
end;

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Iterating All Nodes

// Iterate through all shapes
for i := 0 to Tree.Shapes.Count - 1 do
begin
  Node := Tree.Shapes[i];
  // Process node
end;

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Finding Nodes

// Find by text
Node := Tree.Shapes.Find('Search Text');

// Find by partial match
Node := Tree.Shapes.Find('Search', True);

// Find by object reference
Node := Tree.Shapes.FindObject(MyDataObject);

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Best Practices

Use AutoPosition

Enable AutoPosition for automatic layout management instead of manually positioning every node

Set List Capacity

Pre-allocate list capacity for better performance when adding many nodes

Batch Updates

Use BeginUpdate/EndUpdate when making multiple changes to prevent flickering

Choose Right ChildManager

Select the appropriate child manager for your tree’s visual structure

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Next Steps

Nodes

Learn about TTreeNodeShape and node hierarchy

Connections

Understand how to link nodes with connections

Child Managers

Explore layout management options

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