MS Word pagination using Multiple wpf RichTextBox - wpf

Question

My aim is to make a editor behave similar to MS-Word.Wpf RichTextBox is a wonderful control for it.By placing it inside a ScrollViewer,we can make it editable.(Like a notepad).But I need MS-Word like pages.One effective way probably is to apply style to scrollViewer such that we create a look and feel of multiple pages on richtextbox but I dont know how to do it.What we are doing in the project is to use a documentViewer. Inside a FixedPage,create a Header(Canvas),Body(WpfRichTextBox),Footer(Canvas). And thus create multiple pages,and by subscribing to RichTextBox sizechanged event, we are manually doing the pagination i.e move the blocks from one page to another when height has changed. Do you see any better approach in doing this? Does using multiple richtextboxes hamper my performance?

Answer 1

#WpfProgrammer This is the good approach I would say. Say if you have 1000s of pages then, there will definitely be a performance problem. For avoiding that problem, you need to do demand paging.
Virtual Paging :
1. You need to construct a page table, which will contains pages. Each page will contains information about the controls, images, their positions, dimension and Styles for the page. [All serializable data]
2. Virtual Pages - You need to
de-serialize all the data for the
page and create a page with
RichTextBox. Virtual Pages are
nothing but, pre-cached pages that
are going to be rendered. Say for
example. If I'm in 1st page. Then,
I'll de-seriealize next 3
consecutive pages and have them in a
collection. Then, repeat this
procedure for consecutive page
movements. Adding some logic using
Most Frequently Used collection. It
will be fast enough. In the case of
1000's of pages. You can collapse
those non-dirty or never visited
pages. That could yield little more
performance. If performance is far
more concern for low hardwares.
Then, you should consider
cleaning.
3. Cleaning -
Cleaning is the process of
identifying LFU pages and remove
them. This would be very helpful if
performance is more pronounced.

Answer 2

Hi Tameem
Set the min height,width of the richTextBox to A4 size(lets say). Subscribe to RichTextBox Size Changed event.As soon as the content exceeds,this event gets fired.Then I take the last block of previous page and push it to the first block of next page.(Remember if page doesnot exist, you need to create new page then add it as first block).And also the focus should be changed to the new page.(because if you press enter at the last RTB, you expect the focus to be there in the new page.).When the user deletes a block in some page(say 2nd),then you need to add all the blocks of bottom pages to this page,so that our pagination logic will push the blocks down again and adjust. I can share some piece of code if you need further help.