How do you programmatically apply a css class to an asp.net control?

Question

I\'m wondering how I can apply a CSS class to an ASP.NET Control (TextBox in this case) through the backend in C#. For example:

Answer 1

You can just do this:

 firstName.CssClass = "input left selected".

If you want to append to any existing class names, do this:

firstName.CssClass += " selected";