TTBView

Properties | Methods

Description:

Views arrange items for display and create item viewers (TTBItemViewer) to render individual items.

Each TTBToolbar component has its own TTBView instance, accessible via the View property. Popup menus also have views when they are displayed.

Usage example:

If you have a toolbar named TBToolbar1 and an item on the toolbar named TBItem1, here is how to get the bounding rectangle of TBItem1:

var
  R: TRect;
begin
  R := TBToolbar1.View.Find(TBItem1).BoundsRect;
end;

Key Properties:

• property ParentItem: TTBCustomItem; (Read-only) The item which the view looks in to find items to display. The view then creates item viewers for each item it is going to display.
• property ParentView: TTBView;
  (Read-only) The parent view, or nil if the view is a top-level view.
• property Selected: TTBItemViewer;
  The currently selected item viewer in the view, or nil if there is no selected item viewer. An item viewer becomes "selected" when the mouse is moved over it, or when it is highlighted with the keyboard.
• property Viewers: PTBItemViewerArray;
  (Read-only) The zero-based of array of item viewers (TTBItemViewer) that the view currently owns.
  Note: Access to this property is not range checked.
• property ViewerCount: Integer;
  (Read-only) The number of item viewers available in the Viewers array.
• property Window: TWinControl;
  (Read-only) Specifies the control associated with the view. TTBView will invalidate this control when necessary.

Key Methods:

• procedure BeginUpdate;
  Disables arrangement of item viewers on the view. (TTBToolbar.BeginUpdate calls this.)
• function ContainsView(AView: TTBView): Boolean;
  Returns True if AView is a child view of the view. AView doesn't have to be an immediate child for the function to return True.
• procedure CloseChildPopups;
  Destroys any child views (typically popup menus) that the view is currently displaying.
• procedure DrawSubitems(ACanvas: TCanvas);
  Draws the entire contents of the view on a canvas. TTBToolbar calls this in its Paint method.
• procedure EndUpdate;
  Re-enables item viewer arrangement after a call to BeginUpdate. (TTBToolbar.EndUpdate calls this.)
• function Find(Item: TTBCustomItem): TTBItemViewer;
  Returns the item viewer associated with Item. If the item does not exist on the view, an exception is raised. Therefore it will not return nil.
• function IndexOf(AViewer: TTBItemViewer): Integer;
  Returns the index of the specified item viewer. If AViewer is nil or does not exist, the function returns -1.
• function Invalidate(AViewer: TTBItemViewer);
  Invalidates the area on Window occupied by the item viewer. There is normally no need to call this function directly.
• procedure InvalidatePositions;
  Marks the current item viewer positions as "invalid," causing them to be recalculated and redrawn later. There is normally no need to call this function directly.
• function NextSelectable(CurViewer: TTBItemViewer; GoForward: Boolean): TTBItemViewer;
  Returns the next selectable item viewer following CurViewer (if GoForward is True) or preceding CurViewer (if GoForward is False). CurViewer can be nil, in which case the function will return the first or last selectable item viewer. If no selectable item viewer is found, the function returns nil.
• procedure ScrollSelectedIntoView;
  If the view is a scrolling menu, this procedure adjusts the scroll position if necessary so that the currently selected item viewer is visible.
• procedure TryValidatePositions;
  Same as ValidatePositions, but does not validate if BeginUpdate was called or if ParentItem is currently being loaded.
• procedure ValidatePositions;
  Ensures that all item viewer positions are valid, recalculating them if necessary. There is normally no need to call this function directly.
• function ViewerFromPoint(const P: TPoint): TTBItemViewer;
  Returns the item viewer at the specified point, or nil if no item viewer exists at the specified point. The point is in client coordinates.