ContentPropertyAttribute Class

Definition

Namespace:

System.Windows.Markup

Assembly:

System.Xaml.dll

Indicates which property of a type is the XAML content property. A XAML processor uses this information when processing XAML child elements of XAML representations of the attributed type.

public ref class ContentPropertyAttribute sealed : Attribute

[System.AttributeUsage(System.AttributeTargets.Class, AllowMultiple=false, Inherited=true)]
public sealed class ContentPropertyAttribute : Attribute

[<System.AttributeUsage(System.AttributeTargets.Class, AllowMultiple=false, Inherited=true)>]
type ContentPropertyAttribute = class
    inherit Attribute

Public NotInheritable Class ContentPropertyAttribute
Inherits Attribute

Inheritance

Object

Attribute

ContentPropertyAttribute

Attributes

AttributeUsageAttribute

Examples

The following example creates a class named Film that has a ContentPropertyAttribute applied. The property named Title is indicated as the content property.

[ContentProperty("Title")]
public class Film
{
    public Film()
    {
    }

    public string Title
    {
        get { return _title; }
        set { _title = value; }
    }

    private string _title;
}

<ContentProperty("Title")>
Public Class Film
    Public Sub New()
    End Sub

    Public Property Title() As String
        Get
            Return _title
        End Get
        Set(ByVal value As String)
            _title = value
        End Set
    End Property

    Private _title As String
End Class

Remarks

If the associated property of a ContentPropertyAttribute is not of type string or object, a XAML processor attempts to identify a value conversion technique. The first check is for native type conversion, either of the XAML language primitives or of specific native conversions enabled by that particular XAML writer implementation. The next step is to look for a type converter. In the .NET implementations, a type converter is identified based on TypeConverterAttribute on either the member level or type level definition that applies. If no value conversion can be identified, a XAML object writer typically throws an exception.

In order to accept more than a single object element as content, the type of the XAML content property must be supportable as a collection type.

Because of the Inherited=true declaration of the attribute, a value for a ContentPropertyAttribute normally applies a content property designation to all derived classes as well. Applying an empty ContentPropertyAttribute enables a derived class to remove a declaration of a content property attribute by a base class (and to note that the class has no content property). Applying a differently named ContentPropertyAttribute replaces the inherited ContentPropertyAttribute with the new one.

In previous versions of the .NET Framework, this class existed in the WPF-specific assembly WindowsBase, and also had a parallel implementation in Windows Communication Foundation (WCF). Starting with the .NET Framework 4.0, ContentPropertyAttribute is in the System.Xaml assembly. For more information, see Types Migrated from WPF to System.Xaml.

WPF Usage Notes

An example of a class in Windows Presentation Foundation (WPF) that uses the ContentPropertyAttribute is ContentControl, which the Button class inherits from. The ContentControl.Content property is the content property set by the ContentPropertyAttribute. If a Button is instantiated in XAML, the Content of the Button will be set to the element that is between the start and end button tags.

Constructors

ContentPropertyAttribute()	Initializes a new instance of the ContentPropertyAttribute class.
ContentPropertyAttribute(String)	Initializes a new instance of the ContentPropertyAttribute class, by using the specified name.

Properties

Name	Gets the name of the property that is the content property.
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

• XAML-related CLR attributes for custom types and libraries
• Define custom types for use with .NET XAML Services
• XAML Services