Question

I have two RichTextboxes on my page. I am using them as a Book interface. There are two buttons to turn forward and back.

Traversing through the pages forward works fine. But once I hit back, VS2010 shoots an exception

Element is already the child of another element.

This is for the paragraph I am adding in the RichTextbox. This happen even though I am clearing both the RichTextboxes before flooding them with new data.

My code below. What am I missing?

TxtBlobLeft.Blocks.Clear();
        TxtBlobRight.Blocks.Clear();


        foreach (Paragraph item in pagesStack[count].paras)
        {
            TxtBlobLeft.Blocks.Add(item); //Throws exception here
        }


        foreach (Paragraph item in pagesStack[count + 1].paras)
        {
            TxtBlobRight.Blocks.Add(item);
        }

Note: pagesStack is a custom Object with Paras (i.e List) as a property.

Answer 1

Seems like Clear doesn’t remove the parent reference of Paragraphs to the RTB. I created a new method for Clear using the following forach loop to remove all items.

foreach (Paragraph item in paras)
        {
            Page1.Blocks.Remove(item);
        }

paras is my List of Paragraphs which I had added to the RTB previously.