DataMemberAttribute.EmitDefaultValue Property

 

Gets or sets a value that specifies whether to serialize the default value for a field or property being serialized.

Namespace:   System.Runtime.Serialization
Assembly:  System.Runtime.Serialization (in System.Runtime.Serialization.dll)

public bool EmitDefaultValue { get; set; }

Property Value

Type: System.Boolean

true if the default value for a member should be generated in the serialization stream; otherwise, false. The default is true.

In the .NET Framework, types have a concept of default values. For example, for any reference type the default value is null, 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 EmitDefaultValue property to false (it is true by default).

System_CAPS_noteNote

Setting the EmitDefaultValue 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 EmitDefaultValue 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:nill="true" />
    [DataMember]
    public string EmployeeName = null;

    // This will be written as <employeeID>0</employeeID>
    [DataMember]
    public int employeeID = 0;

    // The next three will not be written because the EmitDefaultValue = false.
    [DataMember(EmitDefaultValue = false)]
    public string position = null;
    [DataMember(EmitDefaultValue = false)]
    public int salary = 0;
    [DataMember(EmitDefaultValue = false)]
    public int? bonus = null;

    // This will be written as <targetSalary>57800</targetSalary> 
    [DataMember(EmitDefaultValue = false)]
    public int targetSalary = 57800;
}

Universal Windows Platform
Available since 8
.NET Framework
Available since 3.0
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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