Difference between revisions of "TNotebook"
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Latest revision as of 23:25, 6 February 2021
TNoteBook is a component that provides a container to hold a variety of controls arranged in pages, much like a real-world notebook. It is a descendant of TWinControl and is available under the Additional tab of the Component Palette.
All pages of the TNotebook are listed by the Pages property, a TStrings class which contains the page names. There is also a property Page (note the singular!) which lists the TPage controls into which other controls can be inserted.
Unlike TPageControl the TNotebook does not have tabs. Therefore, navigation between pages is not as easy as with TPageControl:
- At designtime the pages are listed in the object tree of the Object Inspector under the Notebook node; here the developer can easily switch from page to page.
- At runtime, special code must be provided to show a specific page; the PageIndex property determines which page is currently visible. Here is an example for application of TNotebook in a tabless, wizard-like form with "Forward"/"Backward" buttons to move from page to page:
procedure TForm1.ForwardBtnClick(Sender: TObject); begin if Notebook1.PageIndex < Notebook1.PageCount-1 then Notebook1.PageIndex := Notebook1.PageIndex + 1; end; procedure TForm1.BackwardBtnClick(Sender: TObject); begin if Notebook1.PageIndex > 0 then Notebook1.PageIndex := Notebook1.PageIndex - 1; end;
Pages can be added at designtime by right-clicking on the TNotebook component and selecting Add Page from the context menu.
At runtime, a page is added by calling Notebook.Add('new pagename') with the name of the new page as parameter; the function returns the index of the new page. As already noted, the new page itself can be addressed by using the property Notebook.Page[newindex] (note the singular). The following example adds a new page and puts a TMemo on it:
procedure TForm1.NewPageBtnClick(Sender: TObject); var newIndex: Integer; begin newIndex := Notebook1.Pages.Add('New Page'); // use plural! with TMemo.Create(self) do begin Parent := Notebook1.Page[newIndex]; // use singular! Align := alClient; end; end;
At designtime, a page can be removed by using the context menu of the TNotebook and selecting the menu item Delete Page.
At runtime, a page is removed by deleting the corresponding index from the Pages list (plural!), or by destroying the Page[index] (singular!) at the specific index
procedure TForm1.DeleteCurrPageBtn(Sender: TObject); begin if Notebook1.PageIndex > -1 then Notebook1.Pages.Delete(Notebook1.PageIndex); // or: Notebook1.Page[Notebook1.PageIndex].Free end; end;