This is more or less the same as this question, Difference between HtmlTable and TagBuilder("table") and Why use TagBuilder instead of StringBuilder?
but I want to know that we when you do not have a .Net class for an HTML tag (like iFrame) in System.Web.UI.WebControls and System.Web.UI.HtmlControls then what to use?
@Edit: Can somebody tell me the difference between TagBuilder and HtmlGenericControl ?