CODEWITHSUNDEEP
c#wcfserialization
Paul Keister
Paul Keister

Reputation: 13087

Why Does the DataMemberAttribute Require Special Handling for Boolean Properties

I've noticed that if a Boolean property in a data contract does not emit a default property, e.g.

    [DataMember(Order = 0, IsRequired = true, EmitDefaultValue = false)]
    public bool IsSet { get; set; }

then setting the property to false results in a serialization error. This seems counter-intuitive, because the property has been set, it's just that it's been set to false. The solution is to always configure Boolean properties to emit a default value, then true will come across the wire as true, and false as false.

Just curious: is this a bug in System.Runtime.Serialization or the inevitable result of Boolean type semantics?

Upvotes: 3

Views: 1695

Answers (2)

WhatsUp
WhatsUp

Reputation: 73

To avoid the conflict, you could use nullable bool (bool?) so if the value is explicitly set to false, it will be serialize as expected. Of course, make sure nullable bool data type is something your system can handle.

    [DataMember(Order = 0, IsRequired = true, EmitDefaultValue = false)]
    public bool? IsSet { get; set; }

Upvotes: 0

Tim
Tim

Reputation: 28530

Your question is a little confusing, but I think the behavior you seem to be sqying you're seeing is not a bug, or anything to do with the booleans.

The operation contract is marked with IsRequired set to true. By default, EmitDefaultValue is set to true, but in the posted code it's been set to false.

The EmitDefaultValue attribute indicates whether or not to serialize the value if it is the default value (in other words, if the property was set to false, it would not serialize that property per your current definition).

Since the property is marked as required, if you set the value to false the serialization will fail (if EmitDefaultValue is false) because you're giving contradictory directions - you're saying this property is required for serialization, but don't serialize it if it's the default (false).

In a way I guess you could say it's because of the nature of boolean (it's either true or false, and false is the deafult), but in reality it's because of the way IsRequired and EmitDefaultValue interact.

Take a look at Data Member DefaultValues, specifically the "Interaction with IsRequired" section.

Upvotes: 3

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