DefaultInterfaceAttribute Class

.NET Framework (current version)

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Specifies the default interface of a managed Windows Runtime class.

Namespace:   System.Runtime.InteropServices.WindowsRuntime
Assembly:  mscorlib (in mscorlib.dll)


[AttributeUsageAttribute(AttributeTargets::Class | AttributeTargets::Interface, 
	AllowMultiple = false, Inherited = false)]
public ref class DefaultInterfaceAttribute sealed : Attribute


Initializes a new instance of the DefaultInterfaceAttribute class.


Gets the type of the default interface.


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


This API supports the product infrastructure and is not intended to be used directly from your code. 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.)


Returns a string that represents the current object.(Inherited from Object.)

System_CAPS_pubinterfaceSystem_CAPS_privmethod_Attribute::GetIDsOfNames(Guid%, IntPtr, UInt32, UInt32, IntPtr)

Maps a set of names to a corresponding set of dispatch identifiers.(Inherited from Attribute.)

System_CAPS_pubinterfaceSystem_CAPS_privmethod_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.)

System_CAPS_pubinterfaceSystem_CAPS_privmethod_Attribute::Invoke(UInt32, Guid%, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr)

Provides access to properties and methods exposed by an object.(Inherited from Attribute.)

When you develop Windows Runtime Components, use this attribute when you want to specify the default interface that is used to marshal the class the attribute is applied to. This is not necessary if you allow the class interfaces to be generated automatically.

A Windows Runtime class must have a default interface. If the WinMdExp.exe utility does not detect a default interface for a class when it builds your Windows Runtimecomponent, it chooses an interface as follows:

  • If the class has automatically generated interfaces, it uses the first one as the default.

  • If the class doesn't have any automatically generated interfaces, it uses the first interface in the class's interface implementation list.

You can apply the DefaultInterfaceAttribute attribute to the class, or apply the Windows.Foundations.Metadata.DefaultAttribute attribute to an interface. The latter takes precedence if both attributes are supplied.

Universal Windows Platform
Available since 8
.NET Framework
Available since 4.5
Portable Class Library
Supported in: portable .NET platforms
Windows Phone Silverlight
Available since 8.0
Windows Phone
Available since 8.1

Any public static ( Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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