Nodes

Node configuration

The NodesAppearance property on TTMSFNCTreeView controls the visual style of all nodes. Individual columns can override these defaults by setting UseDefaultAppearance = False on a TTMSFNCTreeViewColumn.

Adding, inserting, and removing nodes

Both collection-based and virtual modes are covered in Modes. The snippets here use collection-based mode.

// Start from a clean state
TreeView1.BeginUpdate;
TreeView1.ClearNodeList;
TreeView1.ClearNodes;
TreeView1.ClearColumns;
TreeView1.Columns.Add.Text := 'Column 1';
TreeView1.EndUpdate;

Add a root node:

var n: TTMSFNCTreeViewNode;
n := TreeView1.AddNode;
n.Text[0] := 'Root Node';

Add a child node:

var pn, child: TTMSFNCTreeViewNode;
pn := TreeView1.AddNode;
child := TreeView1.AddNode(pn);  // child of pn
child.Text[0] := 'Child Node';
TreeView1.ExpandNode(pn);

Insert a node at a specific position:

TreeView1.InsertNode(1, nil);  // insert at index 1 at root level

Remove nodes:

// By method
TreeView1.RemoveNode(TreeView1.FocusedNode);

// By freeing the collection item — same result
TreeView1.FocusedNode.Free;

// Remove all children of a node
TreeView1.RemoveNodeChildren(someParentNode);

// Remove all selected nodes
TreeView1.RemoveSelectedNodes;

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Fixed vs variable node height

Fixed height (default)

All nodes share the same height, set by NodesAppearance.FixedHeight. Icons and text that exceed this height are clipped.

TreeView1.NodesAppearance.FixedHeight := 40;

Variable height

Set NodesAppearance.HeightMode to tnhmVariable to let each node height expand to fit its content (icon size or wrapped text). The NodesAppearance.VariableMinimumHeight sets the minimum height for scroll calculations.

procedure TForm1.SetupVariableHeight;
begin
  TreeView1.BeginUpdate;
  TreeView1.ClearNodeList;
  TreeView1.ClearNodes;
  TreeView1.ClearColumns;
  TreeView1.Columns.Add.Text := 'Variable TreeView';
  TreeView1.Columns[0].WordWrapping := True;
  TreeView1.NodesAppearance.HeightMode := tnhmVariable;
  TreeView1.EndUpdate;
end;

With word wrapping enabled, long text also drives the node height:

TreeView1.Columns[0].WordWrapping := True;
TreeView1.NodesAppearance.HeightMode := tnhmVariable;

---

Checkbox and radiobutton support

Each node column can display a checkbox or radiobutton independently via the CheckTypes property:

procedure TForm1.SetupCheckNodes;
var
  n: TTMSFNCTreeViewNode;
  I: Integer;
begin
  TreeView1.BeginUpdate;
  TreeView1.ClearNodeList;
  TreeView1.ClearNodes;
  TreeView1.ClearColumns;
  TreeView1.Columns.Add.Text := 'Checkbox / radiobutton';

  for I := 0 to 3 do
  begin
    n := TreeView1.Nodes.Add;
    n.Text[0] := 'CheckBox ' + IntToStr(I);
    n.CheckTypes[0] := tvntCheckBox;
    if Odd(I) then
      n.Checked[0] := True;
  end;

  for I := 0 to 3 do
  begin
    n := TreeView1.Nodes.Add;
    n.Text[0] := 'Radiobutton ' + IntToStr(I);
    n.CheckTypes[0] := tvntRadioButton;
    if I = 2 then
      n.Checked[0] := True;
  end;

  TreeView1.EndUpdate;

To use virtual mode for checkboxes, implement OnGetNodeCheckType and OnIsNodeChecked.

Toggle check state programmatically:

TreeView1.ToggleCheckNode(node, 0);           // collection-based
TreeView1.CheckVirtualNode(virtualNode, 0);   // virtual

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Extended nodes

An extended node spans all columns and displays text from column 0 only. Extended nodes are not selectable or editable by default; this can be changed via NodesAppearance.ExtendedSelectable and NodesAppearance.ExtendedEditable.

Use extended nodes as section headers within a flat list:

// Extended nodes that span all columns
procedure TForm1.SetupExtendedNodes;
var
  n, pn: TTMSFNCTreeViewNode;
  I: Integer;
begin
  TreeView1.BeginUpdate;
  TreeView1.ClearNodeList;
  TreeView1.ClearNodes;
  TreeView1.ClearColumns;
  TreeView1.Columns.Add.Text := 'Column 1';
  TreeView1.Columns.Add.Text := 'Column 2';

  pn := TreeView1.Nodes.Add;
  pn.Text[0] := 'Normal Node';

  pn := TreeView1.Nodes.Add;
  pn.Text[0] := 'Extended Group Header';
  pn.Extended := True;

  for I := 0 to 3 do
  begin
    n := TreeView1.AddNode(pn);
    if I = 1 then
    begin
      n.Text[0] := 'Sub-header ' + IntToStr(I);
      n.Extended := True;
    end
    else
    begin
      n.Text[0] := 'Normal Node Column 1 ' + IntToStr(I);
      n.Text[1] := 'Normal Node Column 2 ' + IntToStr(I);
    end;
  end;

  TreeView1.EndUpdate;

In virtual mode, return True from OnIsNodeExtended to mark a node as extended.

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NodesAppearance reference

Property	Description
FixedHeight	Node height when HeightMode = tnhmFixed
HeightMode	tnhmFixed or tnhmVariable
VariableMinimumHeight	Minimum height for variable-height nodes (default 25)
FontColor	Default node text color
Font	Default node font
Fill, Stroke	Default node background and border
SelectedFill, SelectedFontColor	Selected state style
DisabledFill, DisabledFontColor	Disabled state style
LevelIndent	Pixel indent per nesting level
ShowLines	Draw tree connector lines
ShowFocus	Draw focus indicator
ExpandWidth, ExpandHeight	Size of the expand/collapse icon area
SelectionArea	tsaFull — full row, or tsaText — text only

Related API

• TTMSFNCTreeView — AddNode, InsertNode, RemoveNode, ExpandNode, NodesAppearance
• TTMSFNCTreeViewData — TTMSFNCTreeViewNode, TTMSFNCTreeViewVirtualNode

See also

• Modes — virtual vs collection-based approach
• Interaction — editing nodes, filtering, sorting