Отмена вставки нового узла в TreeView 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
      fFinherited;
  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.