/Controls/Samples/LabeledTextBox2/Home.page
<com:TContent ID="body" >
<com:LabeledTextBox
ID="Input"
Label.Text="Username" />
<com:TButton
Text="Submit"
OnClick="buttonClicked" />
<com:TRequiredFieldValidator
ControlToValidate="Input.TextBox"
ErrorMessage="You must enter a value"/>
</com:TContent>