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.