Wpf Replace Text into RichTextBox

Question

I work in WPF C#, i want to replace text into RichtextBox i load my rtf File who contain picture it's work fine.

If i use this :

    ReposLettresFusion m_ReposLettresFusion = new ReposLettresFusion();
    TextRange range = new TextRange(rtb.Document.ContentStart, rtb.Document.ContentEnd); 
    FileStream fStream = new FileStream(@pPath, FileMode.Create);

    range.Text = m_ReposLettresFusion.Fusion(pPkGuidLettre, range.Text);
    range.Save(fStream, DataFormats.Rtf);
    fStream.Close();

    rtb.LoadRtf(pPath);
    m_ReposLettresFusion = null;
    range = null;

It's change my text but i loose my picture and fonts all my formatting.

How i can replace text and keep all formatting of the Rtf

Thank you

Answer 1

Try this :

public void Fusion(ref Xceed.Wpf.Toolkit.RichTextBox pRichTextControl)
        {

            foreach (KeyValuePair<string, string> entry in LettreFusion)
            {
                string keyword = entry.Key;
                string newString = entry.Value;

                TextRange text = new TextRange(pRichTextControl.Document.ContentStart, pRichTextControl.Document.ContentEnd);
                TextPointer current = text.Start.GetInsertionPosition(LogicalDirection.Forward);
                while (current != null)
                {
                    string textInRun = current.GetTextInRun(LogicalDirection.Forward);
                    if (!string.IsNullOrWhiteSpace(textInRun))
                    {
                        int index = textInRun.IndexOf(keyword);
                        if (index != -1)
                        {
                            TextPointer selectionStart = current.GetPositionAtOffset(index, LogicalDirection.Forward);
                            TextPointer selectionEnd = selectionStart.GetPositionAtOffset(keyword.Length, LogicalDirection.Forward);
                            TextRange selection = new TextRange(selectionStart, selectionEnd);
                            selection.Text = newString;
                            pRichTextControl.Selection.Select(selection.Start, selection.End);
                            pRichTextControl.Focus();
                        }
                    }
                    current = current.GetNextContextPosition(LogicalDirection.Forward);
                }
            }
        }