学习 TTreeView [5] TTreeNode.Level 属性

本例效果图:

---

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ComCtrls, StdCtrls, Grids, ExtCtrls;

type
  TForm1 = class(TForm)
    TreeView1: TTreeView;
    Memo1: TMemo;
    Panel1: TPanel;
    Button1: TButton;
    Button2: TButton;
    Button3: TButton;
    procedure FormCreate(Sender: TObject);
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

{初始化 TreeView1}
procedure TForm1.FormCreate(Sender: TObject);
var
  Nodes: TTreeNodes;
  node: TTreeNode;
begin
  TreeView1.Align := alLeft;
  Nodes := TreeView1.Items;
  node := Nodes.Add(nil, '一连长');
  node := Nodes.AddChild(node, '一排长');
  node := Nodes.AddChild(node, '一班长');
  node := Nodes.AddChild(node, '战士1');
  Nodes.Add(node, '战士2');
  Nodes.Add(node, '战士3');
  Nodes.Add(node, '战士4');
  node := node.Parent;
  Nodes.Add(node, '二班长');
  Nodes.Add(node, '三班长');
  node := node.Parent;
  Nodes.Add(node, '二排长');
  Nodes.Add(node, '三排长');
  node := node.Parent;
  Nodes.Add(node, '二连长');
  Nodes.Add(node, '三连长');
end;

{获取元素名列表}
procedure TForm1.Button1Click(Sender: TObject);
var
  i: Integer;
begin
  Memo1.Clear;
  for i := 0 to TreeView1.Items.Count - 1 do
    Memo1.Lines.Add(TreeView1.Items[i].Text);
end;

{使用 Level 属性和 Tab 字符格式化列表}
procedure TForm1.Button2Click(Sender: TObject);
var
  i: Integer;
  s: string;
begin
  Memo1.Clear;
  for i := 0 to TreeView1.Items.Count - 1 do
  begin
    s := StringOfChar(#9, TreeView1.Items[i].Level);
    s := s + TreeView1.Items[i].Text;
    Memo1.Lines.Add(s);
  end;
end;

{上面那个不好看, 这个是用了 4 个空格做 Level 标识}
procedure TForm1.Button3Click(Sender: TObject);
var
  i: Integer;
  s: string;
begin
  Memo1.Clear;
  for i := 0 to TreeView1.Items.Count - 1 do
  begin
    s := StringOfChar(#32, TreeView1.Items[i].Level * 4);
    s := s + TreeView1.Items[i].Text;
    Memo1.Lines.Add(s);
  end;
end;

end.

之前忘了 StringOfChar 函数的存在, 曾经把程序写作:

---

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ComCtrls, StdCtrls, Grids, ExtCtrls;

type
  TForm1 = class(TForm)
    TreeView1: TTreeView;
    Memo1: TMemo;
    Panel1: TPanel;
    Button1: TButton;
    Button2: TButton;
    Button3: TButton;
    procedure FormCreate(Sender: TObject);
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

{初始化 TreeView1}
procedure TForm1.FormCreate(Sender: TObject);
var
  Nodes: TTreeNodes;
  node: TTreeNode;
begin
  TreeView1.Align := alLeft;
  Nodes := TreeView1.Items;
  node := Nodes.Add(nil, '一连长');
  node := Nodes.AddChild(node, '一排长');
  node := Nodes.AddChild(node, '一班长');
  node := Nodes.AddChild(node, '战士1');
  Nodes.Add(node, '战士2');
  Nodes.Add(node, '战士3');
  Nodes.Add(node, '战士4');
  node := node.Parent;
  Nodes.Add(node, '二班长');
  Nodes.Add(node, '三班长');
  node := node.Parent;
  Nodes.Add(node, '二排长');
  Nodes.Add(node, '三排长');
  node := node.Parent;
  Nodes.Add(node, '二连长');
  Nodes.Add(node, '三连长');
end;

{获取元素名列表}
procedure TForm1.Button1Click(Sender: TObject);
var
  i: Integer;
begin
  Memo1.Clear;
  for i := 0 to TreeView1.Items.Count - 1 do
    Memo1.Lines.Add(TreeView1.Items[i].Text);
end;

{使用 Level 属性和 Tab 字符格式化列表}
procedure TForm1.Button2Click(Sender: TObject);
var
  arr: array[0..MAXBYTE] of Char;
  i: Integer;
  s: string;
begin
  Memo1.Clear;
  FillChar(arr, Length(arr), #9);
  for i := 0 to TreeView1.Items.Count - 1 do
  begin
    s := Copy(arr, 0, TreeView1.Items[i].Level);
    s := s + TreeView1.Items[i].Text;
    Memo1.Lines.Add(s);
  end;
end;

{上面那个不好看, 这个是用了 4 个空格做 Level 标识}
procedure TForm1.Button3Click(Sender: TObject);
var
  arr: array[0..MAXBYTE] of Char;
  i: Integer;
  s: string;
begin
  Memo1.Clear;
  FillChar(arr, Length(arr), #32);
  for i := 0 to TreeView1.Items.Count - 1 do
  begin
    s := Copy(arr, 0, TreeView1.Items[i].Level * 4);
    s := s + TreeView1.Items[i].Text;
    Memo1.Lines.Add(s);
  end;
end;

end.