Reads a text-only element. However, we recommend that you use the ReadElementContentAsString method instead, because it provides a more straightforward way to handle this operation.
Assembly: System.Xml (in System.Xml.dll)
The next content node is not a start tag; or the element found does not contain a simple text value.
An XmlReader method was called before a previous asynchronous operation finished. In this case, InvalidOperationException is thrown with the message “An asynchronous operation is already in progress.”