Export (0) Print
Expand All

ComClassAttribute Class

The ComClassAttribute attribute instructs the compiler to add metadata that allows a class to be exposed as a COM object.

System.Object
  System.Attribute
    Microsoft.VisualBasic.ComClassAttribute

Namespace:  Microsoft.VisualBasic
Assembly:  Microsoft.VisualBasic (in Microsoft.VisualBasic.dll)

'Declaration
<AttributeUsageAttribute(AttributeTargets.Class, Inherited := False, AllowMultiple := False)> _
Public NotInheritable Class ComClassAttribute _
	Inherits Attribute

The ComClassAttribute type exposes the following members.

  NameDescription
Public methodComClassAttributeInitializes a new instance of the ComClassAttribute class.
Public methodComClassAttribute(String)Initializes a new instance of the ComClassAttribute class.
Public methodComClassAttribute(String, String)Initializes a new instance of the ComClassAttribute class.
Public methodComClassAttribute(String, String, String)Initializes a new instance of the ComClassAttribute class.
Top

  NameDescription
Public propertyClassIDGets a class ID used to uniquely identify a class.
Public propertyEventIDGets an event ID used to uniquely identify an event.
Public propertyInterfaceIDGets an interface ID used to uniquely identify an interface.
Public propertyInterfaceShadowsIndicates that the COM interface name shadows another member of the class or base class.
Public propertyTypeIdWhen implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute.)
Top

  NameDescription
Public methodEqualsInfrastructure. Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute.)
Public methodGetHashCodeReturns the hash code for this instance. (Inherited from Attribute.)
Public methodGetTypeGets 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 methodToStringReturns a string that represents the current object. (Inherited from Object.)
Top

  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.)
Top

Use ComClassAttribute to simplify the process of exposing COM components from Visual Basic. COM objects are very different from .NET Framework assemblies; without the ComClassAttribute, you need to follow a number of steps to generate a COM object from Visual Basic. For classes marked with ComClassAttribute, the compiler performs many of these steps automatically.

NoteNote

This attribute simplifies the creation of COM objects. To expose a class as a COM object, you must compile the project with the Register for COM Interop option selected in the Build section of the Configuration Properties dialog box.

NoteNote

Although you can also expose a class created with Visual Basic as a COM object for unmanaged code to use, it is not a true COM object. For details, see COM Interoperability in .NET Framework Applications (Visual Basic).

To run this example, create a new Class Library application and add the following code to a class module.

    <ComClass(ComClass1.ClassId, ComClass1.InterfaceId, ComClass1.EventsId)>
    Public Class ComClass1
        ' Use the Region directive to define a section named COM Guids. 
#Region "COM GUIDs" 
        ' These  GUIDs provide the COM identity for this class  
        ' and its COM interfaces. You can generate  
        ' these guids using guidgen.exe 
        Public Const ClassId As String = "7666AC25-855F-4534-BC55-27BF09D49D46" 
        Public Const InterfaceId As String = "54388137-8A76-491e-AA3A-853E23AC1217" 
        Public Const EventsId As String = "EA329A13-16A0-478d-B41F-47583A761FF2"
#End Region

        Public Sub New()
            MyBase.New()
        End Sub 

        Function AddNumbers(ByVal X As Integer, ByVal Y As Integer)
            AddNumbers = X + Y
        End Function 
    End Class

.NET Framework

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

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

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.
Show:
© 2014 Microsoft