Возможность отмены вставки нового узла в TTreeView по нажатию кнопки Esc

unit BetterTreeView;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  ComCtrls, CommCtrl;

type
  TTVNewEditCancelEvent = procedure( Sender: TObject; Node: TTreeNode; var Delete: Boolean) of object;
  TBetterTreeView = class(TTreeView)
  protected
    FIsEditingNew: Boolean;
    FOnEditCancel: TTVChangedEvent;
    FOnNewEditCancel: TTVNewEditCancelEvent;
    procedure Edit(const Item: TTVItem); override;
  public
    function NewChildAndEdit(Node: TTreeNode; const S: string): TTreeNode;
  published
    property IsEditingNew: Boolean read FIsEditingNew;
    property OnEditCancel: TTVChangedEvent read FOnEditCancel write FOnEditCancel;
    property OnNewEditCancel: TTVNewEditCancelEvent read FOnNewEditCancel write FOnNewEditCancel;
end;

implementation

procedure TBetterTreeView.Edit(const Item: TTVItem);
var
  Node: TTreeNode;
  Action: Boolean;
begin
  with Item do
  begin
    { Get the node }
    if (state and TVIF_PARAM) <> 0 then
      Node := Pointer(lParam)
    else
      Node := Items.GetNode(hItem);

    if pszText = nil then
    begin
      if FIsEditingNew then
      begin
        Action := True;
        if Assigned(FOnNewEditCancel) then
          FOnNewEditCancel(Self, Node, Action);
        if Action then
          Node.Destroy
      end
      else
        if Assigned(FOnEditCancel) then
          FOnEditCancel(Self, Node);
    end
    else
      inherited;
  end;
  FIsEditingNew := False;
end;

function TBetterTreeView.NewChildAndEdit(Node: TTreeNode; const S: string): TTreeNode;
begin
  SetFocus;
  Result := Items.AddChild(Node, S);
  FIsEditingNew := True;
  Node.Expand(False);
  Result.EditText;
  SetFocus;
end;

end.