Type Reason InvalidOperationException No element was open, or the XmlWriter.WriteState is WriteState.Closed.
If the element contains no content, a short end tag "/>" is written; otherwise, a full end tag is written.
When you use the System.Xml.XmlWriter methods to output XML, the elements and attributes will not be written until you call the XmlWriter.Close method. For example, if you are using the XmlWwriter to populate an System.Xml.XmlDocument, until you close the System.Xml.XmlWriter, you will not be able to observe the written elements and attributes in the target document.
For the asynchronous version of this method, see XmlWriter.WriteEndElementAsync.