Encodes the value of the specified markup attribute based on the requirements of the System.Web.HttpRequest object of the current context.
A string containing the encoded attribute value, null if value is empty, or the unencoded attribute value if fEncode is false.
Use the HtmlTextWriter.EncodeAttributeValue(string, bool) overload of the HtmlTextWriter.EncodeAttributeValue(HtmlTextWriterAttribute, string) method if the attribute is not an System.Web.UI.HtmlTextWriterAttribute enumeration value or is not known until run time.
The HtmlTextWriter.EncodeAttributeValue(HtmlTextWriterAttribute, string) method removes double quotation marks ("), ampersands (&), and less than signs (<) so that invalid tags are not generated, regardless of the input. The actual encoding is performed by the System.Web.HttpUtility.HtmlAttributeEncode(string) method.