学习 TTreeView [14] - StateIndex(状态图标)、OverlayIndex(叠加图标)

先给 ImageList1 添加图标如下:

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关于 OverlayIndex 的提示:
在给一个节点指定 OverlayIndex 以前, 需要先用 ImageList1.Overlay 指定可用的 OverlayIndex 号.

测试效果图:

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unit Unit1;



interface



uses

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

  Dialogs, ComCtrls, ImgList, StdCtrls, ExtCtrls;



type

  TForm1 = class(TForm)

    TreeView1: TTreeView;

    ImageList1: TImageList;

    Edit1: TEdit;

    Edit2: TEdit;

    Label1: TLabel;

    Label2: TLabel;

    Button1: TButton;

    procedure FormCreate(Sender: TObject);

    procedure Edit1KeyUp(Sender: TObject; var Key: Word; Shift: TShiftState);

    procedure Edit2KeyUp(Sender: TObject; var Key: Word; Shift: TShiftState);

    procedure TreeView1Change(Sender: TObject; Node: TTreeNode);

    procedure Button1Click(Sender: TObject);

  end;



var

  Form1: TForm1;



implementation



{$R *.dfm}



procedure TForm1.FormCreate(Sender: TObject);

var

  node: TTreeNode;

begin

  {指定 ImageList}

  TreeView1.Images      := ImageList1;

  TreeView1.StateImages := ImageList1;



  {设定 OverlayIndex, 最多 4 个}

  ImageList1.Overlay(3,0); {参数1是 ImageList 中的序号; 参数2是指定可选的 OverlayIndex}

  ImageList1.Overlay(4,1);

  ImageList1.Overlay(5,2);

  ImageList1.Overlay(6,3);



  Label1.Caption := 'StateIndex:';

  Label2.Caption := 'OverlayIndex:';



  Edit1.Text := '-1';

  Edit2.Text := '-1';



  Button1.Caption := '初始化';



  {给 TreeView1 填充}

  with TreeView1 do begin

    Align := alLeft;

    Items.Add(nil, 'AAA');

    Items.Add(nil, 'BBB');

    Items.Add(nil, 'CCC');

    Items.Add(nil, 'DDD');

    Items.Add(nil, 'EEE');

    Items.AddChild(Items[4], '111');

    Items.AddChild(Items[4], '222');

    Items.AddChild(Items[4], '333');

    Items.AddChild(Items[4], '444');

  end;



  {指定图标状态}

  for node in TreeView1.Items do

  begin

    node.ImageIndex := 0;    {默认图标为第 0 个}

    node.SelectedIndex := 1; {选择图标为第 1 个}

    node.StateIndex := -1;   {状态图标暂无}

  end;

end;



{Edit1 控制 StateIndex}

procedure TForm1.Edit1KeyUp(Sender: TObject; var Key: Word; Shift: TShiftState);

var

  c: Char;

  edit: TEdit;

begin

  edit := TEdit(Sender);

  c := Chr(Key);

  if c in ['0'..'6'] then edit.Text := c else edit.Text := '-1'; {字符限制}



  TreeView1.Selected.StateIndex := StrToInt(edit.Text);          {作用于 TreeView}

end;



{Edit2 控制 OverlayIndex}

procedure TForm1.Edit2KeyUp(Sender: TObject; var Key: Word; Shift: TShiftState);

var

  c: Char;

  edit: TEdit;

begin

  edit := TEdit(Sender);

  c := Chr(Key);

  if c in ['0'..'3'] then edit.Text := c else edit.Text := '-1'; {字符限制}



  TreeView1.Selected.OverlayIndex := StrToInt(edit.Text);        {作用于 TreeView}

end;



procedure TForm1.TreeView1Change(Sender: TObject; Node: TTreeNode);

begin

  Edit1.Text := IntToStr(Node.StateIndex);

  Edit2.Text := IntToStr(Node.OverlayIndex);

end;



procedure TForm1.Button1Click(Sender: TObject);

begin

  TreeView1.Items.Clear;

  FormCreate(nil);

end;



end.