Ive written some extension methods for various UI components for example here is one for the TextBox
        public static TextBoxBuilder<T> Width<T>(this TextBoxBuilder<T> builder, int width)
        {
            return builder.HtmlAttributes(new { @style = "width:" + width.ToString() + "px" });
        }
However I cant get the syntax correct for the NumericTextBoxBuilder
        public static NumericTextBoxBuilder<T> Width<T>(this NumericTextBoxBuilder<T> builder, int width)
        {
            return builder.HtmlAttributes(new { @style = "width:" + width.ToString() + "px" });
        }
I get a message The type 'T' must be a non-nullable value type in order to use it as parameter 'T' in the generic type or method 'NumericTextBoxBuilder<T>'
I could find an example working on google, can anyone assist