XmlIgnoreAttribute Class

Definition

Namespace:

System.Xml.Serialization

Assembly:

System.Xml.ReaderWriter.dll

Source:

XmlIgnoreAttribute.cs

Instructs the Serialize(TextWriter, Object) method of the XmlSerializer not to serialize the public field or public read/write property value.

public ref class XmlIgnoreAttribute : Attribute

[System.AttributeUsage(System.AttributeTargets.Field | System.AttributeTargets.Parameter | System.AttributeTargets.Property | System.AttributeTargets.ReturnValue)]
public class XmlIgnoreAttribute : Attribute

[<System.AttributeUsage(System.AttributeTargets.Field | System.AttributeTargets.Parameter | System.AttributeTargets.Property | System.AttributeTargets.ReturnValue)>]
type XmlIgnoreAttribute = class
    inherit Attribute

Public Class XmlIgnoreAttribute
Inherits Attribute

Inheritance

Object

Attribute

XmlIgnoreAttribute

Attributes

AttributeUsageAttribute

Examples

The following example shows a class named Group, which contains a field named Comment. The example assigns the XmlIgnoreAttribute to the field, thereby instructing the XmlSerializer to ignore the field when serializing or deserializing an instance of the class.

public ref class Group
{
public:

   // The XmlSerializer ignores this field.

   [XmlIgnore]
   String^ Comment;

   // The XmlSerializer serializes this field.
   String^ GroupName;
};

public class Group
{
   // The XmlSerializer ignores this field.
   [XmlIgnore]
   public string Comment;

   // The XmlSerializer serializes this field.
   public string GroupName;
}

Public Class Group
    ' the XmlSerializer ignores this field.
    <XmlIgnore()> Public Comment As String
    
    ' The XmlSerializer serializes this field.
    Public GroupName As String
End Class

Remarks

The XmlIgnoreAttribute belongs to a family of attributes that controls how the XmlSerializer serializes or deserializes an object. If you apply the XmlIgnoreAttribute to any member of a class, the XmlSerializer ignores the member when serializing or deserializing an instance of the class. For a complete list of similar attributes, see Attributes That Control XML Serialization.

You can override the behavior caused by the XmlIgnoreAttribute by creating an XmlAttributes object, and setting its XmlIgnore property to false. You must Add the XmlAttributes object to an instance of the XmlAttributeOverrides class. Lastly, you must use the XmlAttributeOverrides object to construct an instance of the XmlSerializer class before you call the Serialize or Deserialize methods.

The XML Schema Definition Tool (Xsd.exe) occasionally generates the XmlIgnoreAttribute when creating classes from a schema file (.xsd). This behavior occurs because value types cannot be set to null, but all XML data types can be. Therefore, the tool creates two fields when it encounters an XML type that maps to a value type: one to hold the value and another special field that takes the form of fieldnameSpecified, where the fieldname is replaced by the name of the field or property. Notice, however, that this special field is generated only when the schema specifies that the element has no minimum occurrence (minOccurs = "0") and that the element has no default value. The XmlSerializer sets and checks this special field to determine whether a value has been set for the field or property. Because the special field must not be serialized, the tool applies the XmlIgnoreAttribute to it.

For more information about using attributes, see Attributes.

Note

You can use the word XmlIgnore in your code instead of the longer XmlIgnoreAttribute.

Constructors

XmlIgnoreAttribute()

Initializes a new instance of the XmlIgnoreAttribute class.

Properties

TypeId

When implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute)

Methods

Equals(Object)	Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute)
GetHashCode()	Returns the hash code for this instance. (Inherited from Attribute)
GetType()	Gets the Type of the current instance. (Inherited from Object)
IsDefaultAttribute()	When overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute)
Match(Object)	When overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
ToString()	Returns a string that represents the current object. (Inherited from Object)

See also

• XmlAttributeOverrides
• XmlAttributes
• XmlIgnore
• XmlSerializer
• Introducing XML Serialization
• How to: Specify an Alternate Element Name for an XML Stream
• Controlling XML Serialization Using Attributes
• Examples of XML Serialization
• XML Schema Definition Tool (Xsd.exe)