使用 IntraWeb (19) - 基本控件之 TIWTreeView

這是個飽受非議的控件; 我通過嘗試, 理解了非議, 也能理解作者. 總之向作者的思路靠攏吧, 還是不錯的.

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TIWTreeView 所在單元及繼承鏈:
IWCompTreeview.TIWTreeView < TIWCustomControl < TIWBaseHTMLControl < TIWBaseControl < TIWVCLBaseControl < TControl < TComponent < TPersistent < TObject

主要成員:

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property Items: TIWTreeViewItems    //所有 Item 的集合
property Selected: TIWTreeViewItem  //在這里, 叫做 "當前 Item" 更合適
property AutoIndent: Boolean               //是否自動縮排; 默認 True
property DoServerSidePlusMinus: Boolean    //如果是 True, Html 中不包含被折疊的部分, 需要展開時再從服務器讀取; 相反, Html 中包含所有節點; 默認 False
property TreeViewImages: TIWTreeViewImages //通過其 OpenFolderImage、ClosedFolderImage、DocumentImage、PlusImage、MinusImage 子屬性指定五個圖標
property ItemSpace: TIWTreeViewItemSpace //調整縱、橫間距
property UseItemImages: Boolean          //是否使用 Item 標志圖像
property TreeViewImagesWidth: Integer    //圖標寬度
property TreeViewImagesHeigth: Integer   //圖標高度
property UseFrame: Boolean               //是否使用框架
property ScrollToName: string            //滾動到指定名稱的 Item
property ScrollBars: TIWScrollStyle      //滾動條選項
property WrapItems: Boolean              //Item 文本能否換行; 默認 False
property DoRefreshControl: Boolean       //在修改某些屬性時必須讓它為 True 才會有效

property TreeItemClick: TIWTreeViewClickEvent //通過它可以為每個 Item 指定 Click 事件
property OnPlusMinus: TTreeViewPlusMinusProc  //每當展開或收攏子節點時

procedure ClearAll  //

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TIWTreeViewItems 與 TIWTreeViewItem:

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{IWCompTreeview.TIWTreeViewItems < TOwnedCollection < TCollection < TPersistent < TObject}
property Count: Integer
property Items[AIndex: Integer]: TIWTreeViewItem

function Add(aParentItem: TIWTreeViewItem): TIWTreeViewItem
procedure Clear
procedure Delete(Index: Integer)
function Insert(Index: Integer): TCollectionItem

{IWCompTreeview.TIWTreeViewItem < TCollectionItem < TPersistent < TObject}
property ParentItem: TIWTreeViewItem
property SubItems: TList
property UserData: TObject
property Caption: string
property Expanded: Boolean
property Font: TIWFont
property Hint: string
property ItemImages: TIWTreeViewImages
property Tag: Integer
property URL: string
property Version: Integer
property Css: string
property Collection: TCollection
property ID: Integer
property Index: Integer
property Name: string
property DisplayName: string

property OnClick: TNotifyEvent

procedure DoClick
function HasChild: Boolean

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測試:

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{在空白窗體上放 IWRegion1 和 IWTreeView1; 下面代碼在設計時實現會更方便}
procedure TIWForm1.IWAppFormCreate(Sender: TObject);
var
  fItem: TIWTreeViewItem;
begin
  IWRegion1.Width := 200;
  IWRegion1.Align := alLeft;
  IWRegion1.Color := clWebYellow;
  LinkColor := clWebRed; //如果給 TIWTreeViewItem 指定了 OnClick 事件, 它會被呈現為鏈接

  IWTreeView1.Parent := IWRegion1;
  IWTreeView1.Align := alClient;

  IWTreeView1.Items.Add(nil).Caption := 'ItemA';
  IWTreeView1.Items.Add(nil).Caption := 'ItemB';
  IWTreeView1.Items.Add(nil).Caption := 'ItemC';

  fItem := IWTreeView1.Items.Add(nil);
  fItem.Caption := 'ItemD';
    IWTreeView1.Items.Add(fItem).Caption := 'ItemD1';
    IWTreeView1.Items.Add(fItem).Caption := 'ItemD2';

    fItem := IWTreeView1.Items.Add(fItem);
    fItem.Caption := 'ItemD3';
      IWTreeView1.Items.Add(fItem).Caption := 'ItemD31';
      IWTreeView1.Items.Add(fItem).Caption := 'ItemD32';
end;

{盡管可以為每個 Item 指定 OnClick, 但我覺得用 TreeItemClick 事件一起指定更方便; 事件中可以通過其 Tag、ID、Name、Caption等來區別}
procedure TIWForm1.IWTreeView1TreeItemClick(Sender: TObject; ATreeViewItem: TIWTreeViewItem);
begin
  if not ATreeViewItem.HasChild then
    WebApplication.ShowMessage(ATreeViewItem.Caption);
end;

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效果圖:

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