title: How to format plain text in WPF RichTextBox
body: <p>I have developed a small chat client using WPF. In each chat window, it contains a richtextbox to display previous chat conversations and a textbox with send button to type a chat message.
  I want to format the display text in the richtextbox as shown below.</p>
  
  <p><strong>user1:</strong> <code>chat message goes here</code></p>
  
  <p>For the time being, I use AppendText function to append chat conversation to the richtextbox. my code looks like this, </p>
  
  <pre><code>this.ShowChatConversationsBox.AppendText(from+": "+text);
  </code></pre>
  
  <p>But in this way, i couldn't find a method to format the text as show above. Is there any way to do this? or any alternative methods?</p>
  
  <p>thanks</p>