System.Xml [00 00 00 00 00 00 00 00 04 00 00 00 00 00 00 00] 1.0.5000.0 2.0.0.0 4.0.0.0 To be added System.Xml.Schema.XmlSchemaIdentityConstraint Specifies that an attribute or element value (or set of values) must be a key within the specified scope. A key must be unique, non-nillable/non-nullable, and always present. The constraint name must be unique within a schema. This class represents the key element from XMLSchema as specified by the World Wide Web Consortium (W3C). Constructor 1.0.5000.0 2.0.0.0 4.0.0.0 To be added Initializes a new instance of the class.