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InterfaceTypeAttribute Class

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

System.Object
  System.Attribute
    System.Runtime.InteropServices.InterfaceTypeAttribute

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

[AttributeUsageAttribute(AttributeTargets.Interface, Inherited = false)]
[ComVisibleAttribute(true)]
public sealed class InterfaceTypeAttribute : Attribute

The InterfaceTypeAttribute type exposes the following members.

  NameDescription
Public methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsInterfaceTypeAttribute(ComInterfaceType)Initializes a new instance of the InterfaceTypeAttribute class with the specified ComInterfaceType enumeration member.
Public methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsInterfaceTypeAttribute(Int16)Initializes a new instance of the InterfaceTypeAttribute class with the specified ComInterfaceType enumeration member.
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  NameDescription
Public propertyTypeIdWhen implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute.)
Public propertySupported by Portable Class LibrarySupported in .NET for Windows Store appsValueGets the ComInterfaceType value that describes how the interface should be exposed to COM.
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  NameDescription
Public methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsEqualsInfrastructure. Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute.)
Public methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsGetHashCodeReturns the hash code for this instance. (Inherited from Attribute.)
Public methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodIsDefaultAttributeWhen overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute.)
Public methodMatchWhen overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute.)
Public methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsToStringReturns a string that represents the current object. (Inherited from Object.)
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  NameDescription
Explicit interface implemetationPrivate method_Attribute.GetIDsOfNamesMaps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.GetTypeInfoRetrieves the type information for an object, which can be used to get the type information for an interface. (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.GetTypeInfoCountRetrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.InvokeProvides access to properties and methods exposed by an object. (Inherited from Attribute.)
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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.

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

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.
}

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

.NET for Windows Store apps

Supported in: Windows 8

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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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