title: How to make a specific part of string Bold on richTextBox?
body: <p>I have a chat application that is based on a Form and 2 richTextBoxes !</p>
  
  <p><code>richTextBox1</code> is used to display all conversation<br>
  <code>richTextBox_TextToSend</code> is used to type in the message to send</p>
  
  <p>when a user types a message and hit the enter button, the entered text will appear in richTextBox1</p>
  
  <pre><code>private void button1_Click(object sender, EventArgs e)
      {
          // insert message to database
          if(richTextBox_TextToSend.TextLength&gt;0) {
  
          string txt = richTextBox_TextToSend.Text;
  
          // send the typed message
          sendMessage(from,to,task_id,txt);
  
          // show the typed text in the richTextBox1
          richTextBox1.Text += from+": "+richTextBox_TextToSend.Text+"\n";
          richTextBox_TextToSend.Clear();
  
  
  
          }
      }
  </code></pre>
  
  <p>The variable <code>from</code> of type string holds the name of who send the message (the user using the application) </p>
  
  <p>How to display the name only in bold and other text in normal font style so after typing the message, I see <br><br><strong>Chakib Yousfi</strong> : Hello.... <br><br> instead of 
  <br><br>Chakib Yousfi : Hello...</p>
  
  <p>Any help would be highly appreciated .</p>
  
  <p><img src="https://i.stack.imgur.com/CHb97.png" alt="enter image description here"></p>