XmlSerializer: How to Deserialize an enum value that no longer exists

You can mark the member Obsolete

public enum TypeEnum{    Temperature,    Pressure,    [Obsolete]    Humidity}

It’s generally considered bad practice to remove an enumeration member after your library is already in use. Why don’t you leave the member in place, but mark it with the [Obsolete] attribute to prevent future use? Specifying the ObsoleteAttribute(string,bool) constructor’s second parameter as true would cause a compile-time error if the marked member is accessed.

public enum TypeEnum{    Temperature,    Pressure,    [Obsolete("It's always sunny in Philadelphia", true)]    Humidity,}

To circumvent the error when checking deserialized values, you could compare against the underlying value: typeEnum == (TypeEnum)2.

You can use attributes to change node names around and hide elements from xml serialization, parsing just that one element manually:

public class IOPoint{ public string Name {get; set;} [XmlIgnore] public TypeEnum TypeEnum {get; set;} [XmlElement("TypeEnum")] public string LegacyTypeEnum  {  get { return this.TypeEnum.ToString(); }  set   {    try   {    this.TypeEnum = (TypeEnum)Enum.Parse(typeof(TypeEnum),value);   }   catch(ArgumentException)   {    // Handle "Humidity"   }   catch(OverflowException)   {   }  } }}

Per comments there appears to be some confusion; here is a worked example as a Visual Studio 2010 project. This approach is a simple way of manually parsing only one property of an object (still leveraging the XmlSerializer to do the XML parsing).