I know this was posted a long while ago, and it has been marked answered, but to me, the selected answer was not answering the question I thought the user was posing. It seemed to me he was looking for the approach one can take in ASP .Net that corresponds to his inline data binding previously performed in php.
Here was his php:
<p>Here is the username: <?php echo GetUserName(); ?></p>
Here is what one would do in ASP .Net:
<p>Here is the username: <%= GetUserName() %></p>