Why does a Web Service DataMember's Specified Attribute need to be set for int and Data but not for String

Question

I have created a web service via WCF. Then I exposed it as a web service to make it usable with a .NET 2.0 application. I created some DataContract with DataMember that coul

Answer 1

The default parameters for the DataMember attribute are:

bool EmitDefaultValue (default true)
bool IsRequired (default false)

If the property you are exposing is a non-nullable value type you should use:

[DataMember(IsRequired = true)]
public int InvoiceNo;