Gets or sets a value that specifies whether to serialize the default value for a field or property being serialized.
Assembly: System.Runtime.Serialization (in System.Runtime.Serialization.dll)
In the .NET Framework, types have a concept of default values. For example, for any reference type the default value is Nothing, and for an integer type it is 0. It is occasionally desirable to omit a data member from the serialized data when it is set to its default value. To do this, set the property to false (it is true by default).
Setting the property to false is not a recommended practice. It should only be done if there is a specific need to do so (such as for interoperability or to reduce data size).
The following example shows the property set to false on various fields.
<DataContract()> _ Public Class Employee ' The CLR default for as string is a null value. ' This will be written as <employeeName xsi:nil="true" /> <DataMember()> _ Public employeeName As String = Nothing ' This will be written as <employeeID>0</employeeID> <DataMember()> _ Public employeeID As Integer = 0 ' The next two will not be written because the EmitDefaultValue = false. <DataMember(EmitDefaultValue := False)> Public position As String = Nothing <DataMember(EmitDefaultValue := False)> Public salary As Integer = 0 ' This will be written as <targetSalary>555</targetSalary> because ' the 555 does not match the .NET default of 0. <DataMember(EmitDefaultValue := False)> Public targetSalary As Integer = 555 End Class
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2