Common Windows Presentation Foundation controls don't necessarily provide an intuitive path for upgrading from their Windows Forms equivalents. Take, for example, the RichTextBox control - there is no Rtf property for setting and getting RTF formatted text in WPF's RichTextBox. You can however, still load the RTF text into RichTextBox, using this method (loading RTF text from an embedded resource called MyRtfText):
ASCIIEncoding encoding = new ASCIIEncoding();
byte bytes = encoding.GetBytes(Properties.Resources.MyRtfText);
using (MemoryStream s = new MemoryStream(bytes))
TextRange range = new TextRange(rtfBox.Document.ContentStart, rtfBox.Document.ContentEnd);
But how about creating a couple of text lines that would fit right into WPF's RichTextBox? RichTextBox exposes the Document property, which would accept a FlowDocument - and that's a native WPF content element, persisted in Xaml format. If you need to insert a piece of document into RichTextBox at design time, you'll have to know some Xaml to to it. Having to convert some existing text from RTF or other rich text format (pasting from Word seems like a good idea) requires a converter...
Luckily, such a converter is already built in WPF - it's the RichTextBox itself! The following snippet will stuff the text from the clipboard (text format doesn't matter, as long it's text) into the RichTextBox and get it out as a FlowDocument:
RichTextBox box = new RichTextBox();
TextRange range = new TextRange(box.Document.ContentStart, box.Document.ContentEnd);
using (MemoryStream stream = new MemoryStream())
using (StreamReader reader = new StreamReader(stream))
text = reader.ReadToEnd();
And this is the core of this very simple Visual Studio 2008 Add-In that I've created - it will allow you to paste any text from the clipboard into Visual Studio as XAML.
Installing the Add-In is as easy as copying a DLL, included in the zip file [see link below], into *\My Documents\Visual Studio 2008\Addins folder and (re)start Visual Studio 2008. You'll find the new command under Tools menu.
Download the Add-In. Full Add-In source code will follow...
On a side note... WPF future looks bright: performance and VS Designer improvements, new setup framework, new controls (DataGrid, Ribbon, Calendar, ...) See this ScottGu's post for more details.