XmlnsDefinitionAttribute Class


Specifies a mapping on a per-assembly basis between a XAML namespace and a CLR namespace, which is then used for type resolution by a XAML object writer or XAML schema context.

public ref class XmlnsDefinitionAttribute sealed : Attribute
[System.AttributeUsage(System.AttributeTargets.Assembly, AllowMultiple=true)]
public sealed class XmlnsDefinitionAttribute : Attribute
[<System.AttributeUsage(System.AttributeTargets.Assembly, AllowMultiple=true)>]
type XmlnsDefinitionAttribute = class
    inherit Attribute
Public NotInheritable Class XmlnsDefinitionAttribute
Inherits Attribute


Apply one or more XmlnsDefinitionAttribute attributes to assemblies in order to identify the types within the assembly for XAML usage.

To find the appropriate types that back object element usages or object references in a XAML file, a XAML processor searches each referenced assembly for XmlnsDefinitionAttribute applications. Generally the XAML schema context supplies this information.

In a XAML file, if the xmlns attribute for an object element or property element matches the XmlNamespace in the XmlnsDefinitionAttribute, the XAML processor uses the ClrNamespace and AssemblyName stored in the XmlnsDefinitionAttribute for type resolution against types in the assembly.

In previous versions of the .NET Framework, this class existed in the WPF-specific assembly WindowsBase. In .NET Framework 4, XmlnsDefinitionAttribute is in the System.Xaml assembly. For more information, see Types Migrated from WPF to System.Xaml.


XmlnsDefinitionAttribute(String, String)

Initializes a new instance of the XmlnsDefinitionAttribute class.



Gets or sets the name of the assembly associated with the attribute.


Gets the string name of the CLR namespace specified in this attribute.


When implemented in a derived class, gets a unique identifier for this Attribute.

(Inherited from Attribute)

Gets the XAML namespace identifier specified in this attribute.



Returns a value that indicates whether this instance is equal to a specified object.

(Inherited from Attribute)

Returns the hash code for this instance.

(Inherited from Attribute)

Gets the Type of the current instance.

(Inherited from Object)

When overridden in a derived class, indicates whether the value of this instance is the default value for the derived class.

(Inherited from Attribute)

When overridden in a derived class, returns a value that indicates whether this instance equals a specified object.

(Inherited from Attribute)

Creates a shallow copy of the current Object.

(Inherited from Object)

Returns a string that represents the current object.

(Inherited from Object)

Explicit Interface Implementations

_Attribute.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr)

Maps a set of names to a corresponding set of dispatch identifiers.

(Inherited from Attribute)
_Attribute.GetTypeInfo(UInt32, UInt32, IntPtr)

Retrieves the type information for an object, which can be used to get the type information for an interface.

(Inherited from Attribute)

Retrieves the number of type information interfaces that an object provides (either 0 or 1).

(Inherited from Attribute)
_Attribute.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr)

Provides access to properties and methods exposed by an object.

(Inherited from Attribute)

Applies to

See also