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Overview

TeeTree’s VCL (Visual Component Library) version provides full support for Windows desktop applications using native VCL components and controls. The VCL framework offers optimal performance and native Windows integration.

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Installation

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Unit References

For VCL applications, include the following units in your uses clause: 
uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  ExtCtrls, StdCtrls, TeeProcs, TeeTree, TreeEd;

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Component Placement

Add the TTree component to your VCL form:
  1. Open the Tool Palette in Delphi IDE
  2. Navigate to the TeeTree tab
  3. Drag TTree component onto your form
  4. Set properties in the Object Inspector

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Key VCL Features

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Native Windows Controls

The VCL version uses native Windows GDI/GDI+ for rendering, providing:
  • Fast rendering with hardware acceleration
  • Native scrollbars (TWinControl-based)
  • Standard Windows messages for mouse/keyboard input
  • ImageList integration for node icons
  • Print preview using VCL’s TPrinter

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VCL-Specific Constants

const
  TeeDefaultBoxSize = 4;  // VCL uses smaller default
  crArrowRight = TCursor(2021);  // Custom VCL cursors
  crArrowDown  = TCursor(2022);

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Creating Your First VCL Tree

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Using the Designer

  1. Drop a TTree component on your form
  2. Right-click and select Edit Tree to open the designer
  3. Add nodes using the toolbar buttons
  4. Configure node properties in the Object Inspector
  5. Set up connections between nodes by dragging

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Working with Node Images

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Using ImageList

procedure TForm1.SetupImages;
begin
  // Assign ImageList to Tree
  Tree1.Images := ImageList1;
  
  // Set image index for nodes
  Tree1.Roots[0].ImageListIndex := 0;  // Folder icon
  Tree1.Roots[0].Children[0].ImageListIndex := 1;  // File icon
end;

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VCL-Specific Properties

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Canvas and Drawing

The VCL version uses TCanvas for all drawing operations: 
procedure TForm1.Tree1CustomDraw(Sender: TObject);
var
  R: TRect;
begin
  with Tree1.Canvas do
  begin
    Brush.Color := clWhite;
    Pen.Color := clBlack;
    Pen.Width := 1;
    
    // Custom drawing here
    Rectangle(10, 10, 100, 100);
  end;
end;

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Scrollbars

VCL scrollbars are standard Windows controls: 
procedure TForm1.ConfigureScrollbars;
begin
  Tree1.HorzScrollBar.Automatic := True;
  Tree1.HorzScrollBar.Visible := True;
  
  Tree1.VertScrollBar.Automatic := True;
  Tree1.VertScrollBar.Visible := True;
  
  // Flat style (Windows theme)
  Tree1.HorzScrollBar.Flat := True;
  Tree1.VertScrollBar.Flat := True;
end;

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Printing Support

VCL provides full printing capabilities: 
uses
  Printers;

procedure TForm1.PrintTree;
begin
  with Tree1 do
  begin
    PrintPreview;
    // or
    Print;
  end;
end;

procedure TForm1.ConfigurePrintOptions;
begin
  Tree1.PrintOptions.Orientation := poLandscape;
  Tree1.PrintOptions.Margins.Left := 10;
  Tree1.PrintOptions.Margins.Top := 10;
end;

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Event Handling

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Standard VCL Events

procedure TForm1.Tree1ClickShape(Sender: TTreeNodeShape; 
  Button: TMouseButton; Shift: TShiftState; X, Y: Integer);
begin
  // Handle node click
  ShowMessage('Clicked: ' + Sender.Text[0]);
end;

procedure TForm1.Tree1SelectShape(Sender: TTreeNodeShape);
begin
  // Update status bar
  StatusBar1.SimpleText := 'Selected: ' + Sender.Text[0];
end;

procedure TForm1.Tree1MouseMove(Sender: TObject; Shift: TShiftState; 
  X, Y: Integer);
var
  Node: TTreeNodeShape;
begin
  // Show hint on mouse over
  Node := Tree1.Shapes.Clicked(X, Y);
  if Assigned(Node) then
    Tree1.Hint := Node.Text[0];
end;

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Database Integration

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DBTree Component

VCL includes the TDBTree component for automatic database binding: 
procedure TForm1.SetupDBTree;
begin
  // Connect to dataset
  DBTree1.DataSource := DataSource1;
  
  // Map fields
  DBTree1.MasterField := 'ParentID';
  DBTree1.DetailField := 'ID';
  DBTree1.TextField := 'Name';
  DBTree1.IconField := 'IconIndex';
  
  // Populate from database
  DBTree1.Active := True;
end;

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Performance Optimization

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Large Trees in VCL

For optimal performance with thousands of nodes:
  • Disable AutoSize on nodes
  • Use BeginUpdate/EndUpdate when adding multiple nodes
  • Set appropriate TreeListCapacity values
procedure TForm1.AddManyNodes;
var
  I: Integer;
begin
  // Increase capacity for better performance
  TreeListCapacity := 1000;
  TreeShapeListCapacity := 1000;
  
  Tree1.BeginUpdate;
  try
    for I := 0 to 999 do
      Tree1.Add('Node ' + IntToStr(I));
  finally
    Tree1.EndUpdate;
  end;
end;

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Advanced Features

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Custom Node Shapes

type
  TMyCustomShape = class(TTreeNodeShape)
  protected
    procedure DrawShapeCanvas(const ACanvas: TCanvas3D; 
      const R: TRect); override;
  end;

procedure TMyCustomShape.DrawShapeCanvas(const ACanvas: TCanvas3D; 
  const R: TRect);
begin
  // Custom drawing code
  ACanvas.Pen.Color := clRed;
  ACanvas.Ellipse(R);
end;

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Clipboard Operations

procedure TForm1.CopyToClipboard;
begin
  Tree1.CopyToClipboardMetafile;
  // or
  Tree1.CopyToClipboardBitmap;
end;

procedure TForm1.PasteFromClipboard;
begin
  if Tree1.CanPaste then
    Tree1.Paste;
end;

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Styling and Themes

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Windows Visual Styles

procedure TForm1.ApplyVCLStyles;
begin
  // Enable Windows themes
  Tree1.ParentColor := False;
  Tree1.Color := clWindow;
  
  // Flat scrollbars (themed)
  Tree1.HorzScrollBar.Flat := True;
  Tree1.VertScrollBar.Flat := True;
  
  // Border style
  Tree1.BevelOuter := bvLowered;
  Tree1.BevelInner := bvNone;
end;

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Compatibility

VCL applications are Windows-only. For cross-platform development, use the FMX version instead.

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Supported Delphi Versions

  • Delphi 5 through RAD Studio 13.0 Florence (2025)
  • C++ Builder (all VCL versions)
  • Both 32-bit and 64-bit Windows targets

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Common VCL Patterns

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TreeView Replacement

procedure TForm1.MigrateFromTreeView;
var
  TVNode: TTreeNode;
  TreeNode: TTreeNodeShape;
begin
  // TreeView compatibility mode
  Tree1.GlobalFormat.ChildManager := TTreeExplorerAlignChild;
  
  // Similar API to TTreeView
  TreeNode := Tree1.Add('Item');
  TreeNode.AddChild('SubItem');
  TreeNode.Expanded := True;
  
  // Access like TreeView
  ShowMessage(Tree1.Roots[0].Text[0]);
end;

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See Also

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