CoClassAttribute Class
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CoClassAttribute Class


Specifies the class identifier of a coclass imported from a type library.

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


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


Initializes new instance of the CoClassAttribute with the class identifier of the original coclass.


Gets the class identifier of the original coclass.


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.)

You can apply this attribute to coclass interfaces, although the Tlbimp.exe (Type Library Importer) typically applies it for you when it imports a type library.

When Tlbimp.exe imports a coclass, it produces a managed class and an interface to represent the coclass. The coclass interface has the same interface identifier (IID) as the default interface of the original coclass. The imported coclass interface also retains the name of the coclass. Tlbimp.exe appends the original coclass name with "class" to identify the imported class.

You rarely apply this attribute. However, if plan to write source code that produces metadata that closely simulates metadata produced by Tlbimp.exe, you should create a coclass interface for each coclass. Use the name of the original coclass to name the coclass interface and derive it from the default interface. In addition to the CoClassAttribute, you must also apply the System.Runtime.InteropServices.ComImportAttribute and System.Runtime.InteropServices.GuidAttribute to the coclass interface. For additional information about how Tlbimp.exe imports interfaces and coclasses from a type library, see Imported Type Conversion.

Universal Windows Platform
Available since 4.5
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Available since 2.0
Windows Phone Silverlight
Available since 7.0
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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