学习 TTreeView [2] - Items.Item[i]、Items[i]、.Text、SetFocus(设置焦点)、Select(选择)

本例效果图:

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源码:

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unit Unit1;



interface



uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs, ComCtrls, StdCtrls;



type

  TForm1 = class(TForm)

    TreeView1: TTreeView;

    Button1: TButton;

    Button2: TButton;

    Button3: TButton;

    Button4: TButton;

    procedure Button1Click(Sender: TObject);

    procedure Button2Click(Sender: TObject);

    procedure Button3Click(Sender: TObject);

    procedure Button4Click(Sender: TObject);

  end;



var

  Form1: TForm1;



implementation



{$R *.dfm}



var

  i: Integer;



{这四个按钮的功能是一模一样的}

procedure TForm1.Button1Click(Sender: TObject);

begin

  Self.Text := TreeView1.Items.Item[i].Text;

  if i < TreeView1.Items.Count-1 then Inc(i) else i := 0;



  TreeView1.SetFocus;

  TreeView1.Select(TreeView1.Items.Item[i]);

end;



{TreeView1.Items.Item[i] 是默认属性, 可以简写为: TreeView1.Items[i]}

procedure TForm1.Button2Click(Sender: TObject);

begin

  Text := TreeView1.Items[i].Text;

  if i < TreeView1.Items.Count-1 then Inc(i) else i := 0;



  TreeView1.SetFocus;

  TreeView1.Select(TreeView1.Items[i]);

end;



{每个元素都是 TTreeNode 类型的}

procedure TForm1.Button3Click(Sender: TObject);

var

  node: TTreeNode;

begin

  node := TreeView1.Items[i];

  Text := node.Text;

  if i < TreeView1.Items.Count-1 then Inc(i) else i := 0;



  TreeView1.SetFocus;

  TreeView1.Select(node);

end;



{尽量使用 TTreeNodes 与 TTreeNode}

procedure TForm1.Button4Click(Sender: TObject);

var

  Nodes: TTreeNodes;

  node: TTreeNode;

begin

  Nodes := TreeView1.Items;

  node := Nodes[i];

  Text := node.Text;

  if i < Nodes.Count-1 then Inc(i) else i := 0;



  TreeView1.SetFocus;

  TreeView1.Select(node);

end;



end.