Read Only
In the context of a TextBox, readonly allows the user to set focus to and select and copy the text but not modify it. A disabled TextBox does not allow any interaction whatsoever.
Use ReadOnly when you have data that you want the user to see and copy, but not modify. Use a disabled textbox, when the data you are displaying is not applicable in for the current state of a dialog or window.
Enabled:
Gets or sets a value indicating whether the control can respond to user interaction.