<br />
RichTextBox rtb = new RichTextBox();<br />
TextRange tr = new TextRange(rtb.Document.ContentStart, rtb.Document.ContentEnd);<br />
tr.Select(rtb.Document.Blocks.FirstBlock.ContentStart, rtb.Document.Blocks.FirstBlock.ContentEnd);<br />
see other links
Link1[
^]
Link2[
^]