InterfaceTypeAttribute Class

Definition

Namespace:

System.Runtime.InteropServices

Assembly:

System.Runtime.InteropServices.dll

Source:

InterfaceTypeAttribute.cs

Indicates whether a managed interface is dual, dispatch-only, or IUnknown -only when exposed to COM.

public ref class InterfaceTypeAttribute sealed : Attribute

[System.AttributeUsage(System.AttributeTargets.Interface, Inherited=false)]
public sealed class InterfaceTypeAttribute : Attribute

[<System.AttributeUsage(System.AttributeTargets.Interface, Inherited=false)>]
type InterfaceTypeAttribute = class
    inherit Attribute

Public NotInheritable Class InterfaceTypeAttribute
Inherits Attribute

Inheritance

Object

Attribute

InterfaceTypeAttribute

Attributes

AttributeUsageAttribute

Examples

The following example shows how InterfaceTypeAttribute controls how the interface is exposed to COM.

using namespace System::Runtime::InteropServices;

//Interface is exposed to COM as dual.
interface class IMyInterface1{};

//Insert code here.
//Interface is exposed to COM as IDispatch.

[InterfaceTypeAttribute(ComInterfaceType::InterfaceIsIDispatch)]
interface class IMyInterface2{};
//Insert code here.

using System.Runtime.InteropServices;

//Interface is exposed to COM as dual.
interface IMyInterface1
{
    //Insert code here.
}

//Interface is exposed to COM as IDispatch.
[InterfaceTypeAttribute(ComInterfaceType.InterfaceIsIDispatch)]
interface IMyInterface2
{
    //Insert code here.
}

Imports System.Runtime.InteropServices

'Interface is exposed to COM as dual.
Interface IMyInterface1
     'Insert code here.
End Interface

'Interface is exposed to COM as IDispatch.
<InterfaceTypeAttribute(ComInterfaceType.InterfaceIsIDispatch)> _
Interface IMyInterface2
    'Insert code here.
End Interface

Remarks

You can apply this attribute to interfaces.

By default, the Tlbexp.exe (Type Library Exporter) exposes a managed interface to COM as a dual interface, giving you the flexibility of late binding or the performance of early binding. The ComInterfaceType enumeration enables you to override the default behavior and specify late binding only or early binding only. For example, you can apply InterfaceType (ComInterfaceType.InterfaceIsIDispatch) to an interface to produce metadata to restrict callers to late binding only. Although interfaces that derive from the IDispatch interface are often dual, the InterfaceIsIDispatch enumeration member allows only late-bound calls to the interface methods. This attribute has no effect on the managed view of the interface. For additional information on how interfaces are exposed to COM, see Exported Type Conversion.

The Tlbimp.exe (Type Library Importer) also applies this attribute to imported, nondual interfaces; it applies the appropriate enumeration member to indicate that the interface is dispatch-only or IUnknown -only.

Constructors

InterfaceTypeAttribute(ComInterfaceType)	Initializes a new instance of the InterfaceTypeAttribute class with the specified ComInterfaceType enumeration member.
InterfaceTypeAttribute(Int16)	Initializes a new instance of the InterfaceTypeAttribute class with the specified ComInterfaceType enumeration member.

Properties

TypeId	When implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute)
Value	Gets the ComInterfaceType value that describes how the interface should be exposed to COM.

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

• ComInterfaceType
• Tlbexp.exe (Type Library Exporter)
• Tlbimp.exe (Type Library Importer)