Table of Contents

Interaction

Mouse and keyboard navigation

TTMSFNCTreeView responds to mouse clicks and keyboard navigation out of the box:

  • Click a node to select it.
  • Up/Down, Home, End, Page Up/Down move selection.
  • Left/Right keys collapse and expand nodes.
  • Clicking the expand/collapse icon has the same effect.

Multi-select

TreeView1.Interaction.MultiSelect := True;
// Use Ctrl+click or Shift+click to select multiple nodes

Retrieve selected nodes:

var
  I: Integer;
begin
  for I := 0 to TreeView1.SelectedNodeCount - 1 do
    ShowMessage(TreeView1.SelectedNodes[I].Text[0]);
end;

Select all:

TreeView1.SelectAllNodes;       // collection-based
TreeView1.SelectAllVirtualNodes; // virtual

Mouse wheel sensitivity

Control how much the tree scrolls per wheel notch:

TreeView1.Interaction.MouseWheelDelta := 2;  // scroll 2 node heights per notch

Inplace editing

Enable editing per column via the EditorType property:

TreeView1.Columns[0].EditorType := tcetEdit;      // standard TEdit
TreeView1.Columns[1].EditorType := tcetComboBox;  // TComboBox with fixed list
TreeView1.Columns[1].EditorItems.Add('Option A');
TreeView1.Columns[1].EditorItems.Add('Option B');
ComboBox inplace editor

Start editing with a click on the text or by pressing F2.

Control text when editing starts via OnGetNodeText:

procedure TForm1.TreeView1GetNodeText(Sender: TObject;
  ANode: TTMSFNCTreeViewVirtualNode; AColumn: Integer;
  AMode: TTMSFNCTreeViewNodeTextMode; var AText: string);
begin
  if AMode = tntmEditing then
    AText := '';  // start with a blank editor
end;

Validate before committing:

procedure TForm1.TreeView1BeforeUpdateNode(Sender: TObject;
  ANode: TTMSFNCTreeViewVirtualNode; AColumn: Integer;
  var AText: string; var ACanUpdate: Boolean);
begin
  if AText = '' then
    ACanUpdate := False;  // reject empty
end;

Custom editor

Supply any TControl subclass as the inplace editor:

TreeView1.Columns[1].CustomEditor := True;

procedure TForm1.TreeView1GetInplaceEditor(Sender: TObject;
  ANode: TTMSFNCTreeViewVirtualNode; AColumn: Integer;
  var ATransparent: Boolean;
  var AInplaceEditorClass: TTMSFNCTreeViewInplaceEditorClass);
begin
  AInplaceEditorClass := TTrackBar;
end;

procedure TForm1.TreeView1BeforeUpdateNode(Sender: TObject;
  ANode: TTMSFNCTreeViewVirtualNode; AColumn: Integer;
  var AText: string; var ACanUpdate: Boolean);
begin
  AText := FloatToStr((TreeView1.GetInplaceEditor as TTrackBar).Value);
end;
Custom TrackBar editor

Lookup

When Interaction.Lookup.Enabled is True, typing alphanumeric characters navigates to the node whose text starts with the typed string:

TreeView1.Interaction.Lookup.Enabled := True;

Filtering

Filtering hides nodes that don't match a condition while keeping their ancestors visible so the tree stays navigable. Enable column-header filter dropdowns or apply a programmatic filter via the Filter collection.

// Enable or disable filtering on a per-column basis
TreeView1.Columns[0].Filtering.Enabled := True;
TreeView1.Columns[1].Filtering.Enabled := False;

Adds a filter button to the column header. Clicking it shows a dropdown list of unique values; selecting one filters the tree.

TreeView1.Columns[0].Filtering.Enabled := True;
Filter dropdown open

Programmatic filter

procedure TForm1.ApplyFilter;
var
  f: TTMSFNCTreeViewFilterData;
begin
  TreeView1.Filter.Clear;

  f := TreeView1.Filter.Add;
  f.Column := 0;
  f.Condition := '*A*';  // wildcard match on column 0

  f := TreeView1.Filter.Add;
  f.Column := 1;
  f.Condition := '>= 2010';  // range match on column 1

  TreeView1.ApplyFilter;
end;
Filtered tree showing only matching nodes
Note

When a child node matches the filter condition, its entire parent chain is also shown so the tree structure remains navigable.

Remove all active filters:

TreeView1.RemoveFilters;

Sorting

Enable click-to-sort on a column:

TreeView1.Columns[0].Sorting := tcsRecursive;  // also sorts child nodes
Sorted TreeView

Sort programmatically:

TreeView1.Sort(0, True, False, nsmDescending);
// parameters: column index, recursive, case-sensitive, sort direction

Clipboard

TreeView1.Interaction.ClipboardMode := tcmFull;
// tcmTextOnly — copies text only
// tcmFull     — copies all node attributes (text, icons, check states)

Cut/Copy/Paste are handled via standard keyboard shortcuts (Ctrl+X, Ctrl+C, Ctrl+V). When pasting, the focused node becomes the parent of the pasted nodes; if no node is focused, pasted nodes are added at root level.

Reordering and drag-and-drop

Reordering within the same level

TreeView1.Interaction.Reorder := True;
// Click an already-selected node and drag to a new position
Node being reordered

Drag-and-drop

TreeView1.Interaction.DragDropMode := tdmMove;  // or tdmCopy
// Drag-and-drop takes precedence over reorder
// Supports moving nodes between two different TTMSFNCTreeView instances

Drag-and-drop events: OnBeforeDropNode, OnAfterDropNode, OnAfterReorderNode.

Combined example: filtering + sorting + editing

  var ACanUpdate: Boolean);
begin
  // Validate or transform the text before it is committed
  if (AColumn = 0) and (AText = '') then
    ACanUpdate := False;  // reject empty text
end;

// Clipboard
procedure TForm1.SetupClipboard;
begin

Interaction property reference

Property Description
ClipboardMode tcmNone, tcmTextOnly, tcmFull
ColumnAutoSizeOnDblClick Autosize a column by double-clicking the header splitter
ColumnSizing Allow the user to resize columns by dragging
DragDropMode tdmNone, tdmMove, tdmCopy
ExtendedEditable Allow editing extended (section-header) nodes
ExtendedSelectable Allow selecting extended nodes
KeyboardEdit Start editing with F2 or direct typing
Lookup.Enabled Type-to-navigate
MouseEditMode When mouse click starts editing
MouseWheelDelta Scroll sensitivity (node heights per wheel notch)
MultiSelect Allow Ctrl/Shift multi-selection
ReadOnly Disable all editing
Reorder Enable drag-reorder within the same level
TouchScrolling Enable inertial touch scroll

See also