如何将Treeview的一部分复制到菜单

Question

我正在尝试将Treeview的一部分复制到弹出菜单中,并且根本没有任何运气我似乎无法获得递归工作,我知道我可能做错了.

以此示例图像(这是以下代码中的运行时屏幕截图):

我需要创建与Treeview具有相同关系的菜单,但我不想添加Root项.这就是我想要的样子:

请注意,第一项不是设置图标(Root),而是它们处于Treeview之类的级别.

这是我的代码:

unit Unit1;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, ComCtrls,
  Menus, StdCtrls, Buttons;

type
  TForm1 = class(TForm)
    Button1: TButton;
    ImageList1: TImageList;
    MenuItem1: TMenuItem;
    PopupMenu1: TPopupMenu;
    TreeView1: TTreeView;
    procedure MyMenuItemClick(Sender: TObject);
    procedure Button1Click(Sender: TObject);
  private
    procedure TreeViewToMenu(TreeView: TTreeView; BaseNode: TTreeNode; OutMenu: TMenu);
  public
    { public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.lfm}

procedure TForm1.MyMenuItemClick(Sender: TObject);
begin
  ShowMessage('You selected ' + TMenuItem(Sender).Name + ' - Tag: ' +
    IntToStr(TMenuItem(Sender).Tag));
end;

procedure TForm1.TreeViewToMenu(TreeView: TTreeView; BaseNode: TTreeNode; OutMenu: TMenu);
var
  I: Integer;
  MenuItem: TMenuItem;
begin
  MenuItem := TMenuItem.Create(nil);
  with MenuItem do
  begin
    Caption := BaseNode.Text;
    ImageIndex := BaseNode.ImageIndex;
    OnClick := @MyMenuItemClick;
  end;

  for I := 0 to BaseNode.Count - 1 do
  begin
    MenuItem.Tag := I;
    TreeViewToMenu(TreeView, BaseNode[I], OutMenu);
  end;

  OutMenu.Items.Add(MenuItem);
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  Pt: TPoint;
  I: Integer;
  Node: TTreeNode;
begin
  Pt.X := Button1.Left + 1;
  Pt.Y := Button1.Top + Button1.Height + 1;
  Pt := ClientToScreen(Pt);

  PopupMenu1.Items.Clear;
  TreeViewToMenu(TreeView1, TreeView1.Items[0], PopupMenu1);

  PopupMenu1.Popup(Pt.X, Pt.Y);
end;

end.

我还尝试添加到MenuItem Tag属性,以便我可以通过其标记识别每个菜单项.

我认为递归基本上意味着从程序中再次调用该过程,所以它重复自己,无论哪种方式,我真的可以做一些帮助.

谢谢.

Answer 1

您对递归调用的理解没有问题,但您不希望为根节点附加项,因此您应该为传递给该过程的任何节点的每个子项添加一个项并递归.这是一个示例实现:

type
  TForm1 = class(TForm)
    ..
  private
    procedure TreeViewToMenu(BaseNode: TTreeNode; OutMenu: TComponent);
    ..

procedure TForm1.TreeViewToMenu(BaseNode: TTreeNode; OutMenu: TComponent);
var
  i: Integer;
  Node: TTreeNode;
  MenuItem: TMenuItem;
begin
  for i := 0 to BaseNode.Count - 1 do begin
    Node := BaseNode.Item[i];

    MenuItem := TMenuItem.Create(nil);
    MenuItem.Caption := Node.Text;
    MenuItem.ImageIndex := Node.ImageIndex;
    MenuItem.Tag := i;
    if Node.Count = 0 then
      MenuItem.OnClick := MyMenuItemClick;

    if OutMenu is TPopupMenu then
      TMenu(OutMenu).Items.Add(MenuItem)
    else if
      OutMenu is TMenuItem then
        TMenuItem(OutMenu).Add(MenuItem)
      else
        raise Exception.Create('Invalid class type');

    TreeViewToMenu(Node, MenuItem);

  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  ..
begin
  ..
  TreeViewToMenu(TreeView1.Items[0], PopupMenu1);
  ..

请注意,我更改了TreeViewToMenufor 的声明(1)未使用TreeView和(2)我们将项目附加到a TPopupMenu或a TMenuItem,因此我声明'OutMenu' TComponent将接受两者.