When overridden in a derived class, gets a value indicating whether the current node is an attribute that was generated from the default value defined in the DTD or schema.
A bool where true indicates the current node is an attribute whose value was generated from the default value defined in the DTD or schema; false indicates the attribute value was explicitly set.
IsDefault always returns false for implementations of XmlReader that do not support schema or DTD information. This property applies only to an attribute node.