XHtmlOptions UseTheme Property. Whether to use themes. ABCpdf .NET PDF Library. From ABCpdf .net previous page next page UseTheme Property Type Default Value Read Only Description [C#] bool [Visual Basic] Boolean false Yes Whether to use themes. Notes This property determines whether UI theme is applied to controls. The theme is only relevant if you are using the MSHTML engine for IE9 or earlier. As such it is likely that this function will be deprecated in future releases of ABCpdf. To change the value, use SetTheme. Example None. previous page start next page