System.Runtime.InteropServices Namespace

.NET Framework Class Library

The System.Runtime.InteropServices namespace provides a wide variety of members that support COM interop and platform invoke services. If you are unfamiliar with these services, see Interoperating with Unmanaged Code.

Members of this namespace provide several categories of functionality, as shown in the following table. Attributes control marshaling behavior, such as how to arrange structures or how to represent strings. The most important attributes are DllImportAttribute, which you use to define platform invoke methods for accessing unmanaged APIs, and MarshalAsAttribute, which you use to specify how data is marshaled between managed and unmanaged memory.

Category	Members
Attributes	AutomationProxyAttribute, BestFitMappingAttribute, ClassInterfaceAttribute, ComAliasNameAttribute, ComCompatibleVersionAttribute, ComConversionLossAttribute, ComImportAttribute, ComRegisterFunctionAttribute, ComSourceInterfacesAttribute, ComUnregisterFunctionAttribute, ComVisibleAttribute, DispIdAttribute, DllImportAttribute, FieldOffsetAttribute, GuidAttribute, IDispatchImplType, ImportedFromTypeLibAttribute, InAttribute, InterfaceTypeAttribute, LCIDConversionAttribute, MarshalAsAttribute, OptionalAttribute, OutAttribute, PreserveSigAttribute, PrimaryInteropAssemblyAttribute, ProgIdAttribute, StructLayoutAttribute, TypeLibFuncAttribute, TypeLibTypeAttribute, TypeLibVarAttribute, TypeLibVersionAttribute Associated enumerations: ClassInterfaceType, CallingConvention, CharSet, IDispatchImplType, ComInterfaceType, VarEnum, UnmanagedType, LayoutKind, TypeLibFuncFlags, TypeLibTypeFlags, TypeLibVarFlags
Custom instantiation	ExtensibleClassFactory, ICustomFactory, ObjectCreationDelegate
Custom marshaling	ICustomAdapter, ICustomMarshaler
Exceptions	COMException, ExternalException, InvalidComObjectException, InvalidOleVariantTypeException, MarshalDirectiveException, SafeArrayRankMismatchException, SafeArrayTypeMismatchException, SEHException
Helper classes	ArrayWithOffset, GCHandle, HandleRef, Marshal, RuntimeEnvironment Associated enumerations: ComMemberType, GCHandleType
.NET-based definitions for COM types	COM interfaces: UCOMIBindCtx, UCOMIConnectionPoint, UCOMIConnectionPointContainer, UCOMIEnumConnectionPoints, UCOMIEnumConnections, UCOMIEnumMoniker, UCOMIEnumString, UCOMIEnumVARIANT, UCOMIMoniker, UCOMIPersistFile, UCOMIRunningObjectTable, UCOMIStream, UCOMITypeComp, UCOMITypeInfo, UCOMITypeLib COM structures and unions: BINDPTR, BIND_OPTS, CONNECTDATA, DISPPARAMS, ELEMDESC, EXCEPINFO, FILETIME, FUNCDESC, IDLDESC, PARAMDESC, STATSTG, TYPEATTR, TYPEDESC, TYPELIBATTR, VARDESC COM enumerations: CALLCONV, DESCKIND, FUNCFLAGS, FUNCKIND, IDLFLAG, IMPLTYPEFLAGS, INVOKEKIND, LIBFLAGS, PARAMFLAG, SYSKIND, TYPEFLAGS, TYPEKIND, VarEnum, VARFLAGS
Tool APIs	Type Library Importer: ImporterEventKind, ITypeLibConverter, ITypeLibImporterNotifySink, TypeLibConverter, TypeLibImporterFlags Type Library Exporter: ExporterEventKind, ITypeLibConverter, ITypeLibExporterNotifySink, TypeLibConverter, TypeLibExporterFlags Assembly Registration: AssemblyRegistrationFlags, IRegistrationServices, RegistrationServices
VARIANT type wrappers	CurrencyWrapper, DispatchWrapper, ErrorWrapper, UnknownWrapper

Namespace hierarchy

Classes

Class	Description
AutomationProxyAttribute	Specifies whether the type should be marshaled using the Automation marshaler or a custom proxy and stub.
BestFitMappingAttribute	Controls whether Unicode characters are converted to the closest matching ANSI characters.
ClassInterfaceAttribute	Indicates the type of class interface to be generated for a class exposed to COM, if an interface is generated at all.
CoClassAttribute	Specifies the class identifier of a coclass imported from a type library.
ComAliasNameAttribute	Indicates the COM alias for a parameter or field type.
ComCompatibleVersionAttribute	Indicates to a COM client that all classes in the current version of an assembly are compatible with classes in an earlier version of the assembly.
ComConversionLossAttribute	Indicates that information was lost about a class or interface when it was imported from a type library to an assembly.
ComEventInterfaceAttribute	Identifies the source interface and the class that implements the methods of the event interface that is generated when a coclass is imported from a COM type library.
COMException	The exception that is thrown when an unrecognized HRESULT is returned from a COM method call.
ComImportAttribute	Indicates that the attributed type was previously defined in COM.
ComRegisterFunctionAttribute	Specifies the method to call when you register an assembly for use from COM; this allows for the execution of user-written code during the registration process.
ComSourceInterfacesAttribute	Identifies a list of interfaces that are exposed as COM event sources for the attributed class.
ComUnregisterFunctionAttribute	Specifies the method to call when you unregister an assembly for use from COM; this allows for the execution of user-written code during the unregistration process.
ComVisibleAttribute	Controls accessibility of an individual managed type or member, or of all types within an assembly, to COM.
CurrencyWrapper	Wraps objects the marshaler should marshal as a VT_CY.
DispatchWrapper	Wraps objects the marshaler should marshal as a VT_DISPATCH.
DispIdAttribute	Specifies the COM dispatch identifier (DISPID) of a method, field, or property.
DllImportAttribute	Indicates that the attributed method is exposed by an unmanaged dynamic-link library (DLL) as a static entry point.
ErrorWrapper	Wraps objects the marshaler should marshal as a VT_ERROR.
ExtensibleClassFactory	Enables customization of managed objects that extend from unmanaged objects during creation.
ExternalException	The base exception type for all COM interop exceptions and structured exception handling (SEH) exceptions.
FieldOffsetAttribute	Indicates the physical position of fields within the unmanaged representation of a class or structure.
GuidAttribute	Supplies an explicit System.Guid when an automatic GUID is undesirable.
IDispatchImplAttribute	Indicates which IDispatch implementation the common language runtime uses when exposing dual interfaces and dispinterfaces to COM.
ImportedFromTypeLibAttribute	Indicates that the types defined within an assembly were originally defined in a type library.
InAttribute	Indicates that data should be marshaled from the caller to the callee, but not back to the caller.
InterfaceTypeAttribute	Indicates whether a managed interface is dual, dispatch-only, or IUnknown-only when exposed to COM.
InvalidComObjectException	The exception thrown when an invalid COM object is used.
InvalidOleVariantTypeException	The exception thrown by the marshaler when it encounters an argument of a variant type that can not be marshaled to managed code.
LCIDConversionAttribute	Indicates that a method's unmanaged signature expects a locale identifier (LCID) parameter.
Marshal	Provides a collection of methods for allocating unmanaged memory, copying unmanaged memory blocks, and converting managed to unmanaged types, as well as other miscellaneous methods used when interacting with unmanaged code.
MarshalAsAttribute	Indicates how to marshal the data between managed and unmanaged code.
MarshalDirectiveException	The exception that is thrown by the marshaler when it encounters a MarshalAsAttribute it does not support.
OptionalAttribute	Indicates that a parameter is optional.
OutAttribute	Indicates that data should be marshaled from callee back to caller.
PreserveSigAttribute	Indicates that the HRESULT or retval signature transformation that takes place during COM interop calls should be suppressed.
PrimaryInteropAssemblyAttribute	Indicates that the attributed assembly is a primary interop assembly.
ProgIdAttribute	Allows the user to specify the ProgID of a class.
RegistrationServices	Provides a set of services for registering and unregistering managed assemblies for use from COM.
RuntimeEnvironment	Provides a collection of static (Shared in Visual Basic) methods that return information about the common language runtime environment.
SafeArrayRankMismatchException	The exception thrown when the rank of an incoming SAFEARRAY does not match the rank specified in the managed signature.
SafeArrayTypeMismatchException	The exception thrown when the type of the incoming SAFEARRAY does not match the type specified in the managed signature.
SEHException	Represents Structured Exception Handler (SEH) errors.
StructLayoutAttribute	The StructLayoutAttribute class allows the user to control the physical layout of the data fields of a class or structure.
TypeLibConverter	Provides a set of services that convert a managed assembly to a COM type library and vice versa.
TypeLibFuncAttribute	Contains the FUNCFLAGS that were originally imported for this method from the COM type library.
TypeLibTypeAttribute	Contains the TYPEFLAGS that were originally imported for this type from the COM type library.
TypeLibVarAttribute	Contains the VARFLAGS that were originally imported for this field from the COM type library.
TypeLibVersionAttribute	Specifies the version number of an exported type library.
UnknownWrapper	Wraps objects the marshaler should marshal as a VT_UNKNOWN.

Interfaces

Interface	Description
ICustomAdapter	Provides a way for clients to access the actual object, rather than the adapter object handed out by a custom marshaler.
ICustomFactory	Enables users to write activation code for managed objects that extend MarshalByRefObject.
ICustomMarshaler	Designed to provide custom wrappers for handling method calls.
IRegistrationServices	Provides a set of services for registering and unregistering managed assemblies for use from COM.
ITypeLibConverter	Provides a set of services that convert a managed assembly to a COM type library and vice versa.
ITypeLibExporterNameProvider	Provides control over the casing of names when exported to a type library.
ITypeLibExporterNotifySink	Provides a callback mechanism for the assembly converter to inform the caller of the status of the conversion, and involve the caller in the conversion process itself.
ITypeLibImporterNotifySink	Provides a callback mechanism for the type library converter to inform the caller of the status of the conversion, and involve the caller in the conversion process itself.
UCOMIBindCtx	Managed definition of the IBindCtx interface.
UCOMIConnectionPoint	Managed definition of the IConnectionPoint interface.
UCOMIConnectionPointContainer	Managed definition of the IConnectionPointContainer interface.
UCOMIEnumConnectionPoints	Manages the definition of the IEnumConnectionPoints interface.
UCOMIEnumConnections	Manages the definition of the IEnumConnections interface.
UCOMIEnumMoniker	Manages the definition of the IEnumMoniker interface.
UCOMIEnumString	Manages the definition of the IEnumString interface.
UCOMIEnumVARIANT	Manages the definition of the IEnumVARIANT interface.
UCOMIMoniker	Managed definition of the IMoniker interface, with COM functionality from IPersist and IPersistStream.
UCOMIPersistFile	Managed definition of the IPersistFile interface, with functionality from IPersist.
UCOMIRunningObjectTable	Managed definition of the IRunningObjectTable interface.
UCOMIStream	Managed definition of the IStream interface, with ISequentialStream functionality.
UCOMITypeComp	Managed definition of the ITypeComp interface.
UCOMITypeInfo	Managed definition of the ITypeInfo interface.
UCOMITypeLib	Managed definition of the ITypeLib interface.

Structures

Structure	Description
ArrayWithOffset	Encapsulates an array and an offset within the specified array.
BINDPTR	Contains a pointer to a bound-to FUNCDESC, VARDESC, or an ITypeComp interface.
BIND_OPTS	Stores the parameters that are used during a moniker-binding operation.
CONNECTDATA	Describes a connection that exists to a given connection point.
DISPPARAMS	Contains the arguments passed to a method or property by IDispatch::Invoke.
ELEMDESC	Contains the type description and process transfer information for a variable, function, or a function parameter.
ELEMDESC.DESCUNION	Contains information about an element.
EXCEPINFO	Describes the exceptions that occur during IDispatch::Invoke.
FILETIME	This structure is a 64-bit value representing the number of 100-nanosecond intervals since January 1, 1601.
FUNCDESC	Defines a function description.
GCHandle	Provides a means for accessing a managed object from unmanaged memory.
HandleRef	Wraps a managed object holding a handle to a resource that is passed to unmanaged code using platform invoke.
IDLDESC	Contains information needed for transferring a structure element, parameter, or function return value between processes.
PARAMDESC	Contains information about how to transfer a structure element, parameter, or function return value between processes.
STATSTG	Contains statistical information about an open storage, stream, or byte-array object.
TYPEATTR	Contains attributes of a UCOMITypeInfo.
TYPEDESC	Describes the type of a variable, return type of a function, or the type of a function parameter.
TYPELIBATTR	Identifies a particular type library and provides localization support for member names.
VARDESC	Describes a variable, constant, or data member.
VARDESC.DESCUNION	Contains information about a variable.

Delegates

Delegate	Description
ObjectCreationDelegate	Creates a COM object.

Enumerations

Enumeration	Description
AssemblyRegistrationFlags	Defines a set of flags used when registering assemblies.
CALLCONV	Identifies the calling convention used by a method described in a METHODDATA structure.
CallingConvention	Specifies the calling convention required to call methods implemented in unmanaged code.
CharSet	Dictates which character set marshaled strings should use.
ClassInterfaceType	Identifies the type of class interface that is generated for a class.
ComInterfaceType	Identifies how to expose an interface to COM.
ComMemberType	Describes the type of a COM member.
DESCKIND	Identifies the type description being bound to.
ExporterEventKind	Describes the callbacks that the type library exporter makes when exporting a type library.
FUNCFLAGS	Identifies the constants that define the properties of a function.
FUNCKIND	Defines how to access a function.
GCHandleType	Represents the types of handles the GCHandle class can allocate.
IDispatchImplType	Indicates which IDispatch implementation to use for a particular class.
IDLFLAG	Describes how to transfer a structure element, parameter, or function return value between processes.
IMPLTYPEFLAGS	Defines the attributes of an implemented or inherited interface of a type.
ImporterEventKind	Describes the callbacks that the type library importer makes when importing a type library.
INVOKEKIND	Specifies how to invoke a function by IDispatch::Invoke.
LayoutKind	Controls the layout of an object when exported to unmanaged code.
LIBFLAGS	Defines flags that apply to type libraries.
PARAMFLAG	Describes how to transfer a structure element, parameter, or function return value between processes.
SYSKIND	Identifies the target operating system platform.
TYPEFLAGS	Defines the properties and attributes of a type description.
TYPEKIND	Specifies various types of data and functions.
TypeLibExporterFlags	Indicates how a type library should be produced.
TypeLibFuncFlags	Describes the original settings of the FUNCFLAGS in the COM type library from where this method was imported.
TypeLibImporterFlags	Indicates how an assembly should be produced.
TypeLibTypeFlags	Describes the original settings of the TYPEFLAGS in the COM type library from which the type was imported.
TypeLibVarFlags	Describes the original settings of the VARFLAGS in the COM type library from which the variable was imported.
UnmanagedType	Identifies how to marshal parameters or fields to unmanaged code.
VarEnum	Indicates how to marshal the array elements when an array is marshaled from managed to unmanaged code as a UnmanagedType.SafeArray.
VARFLAGS	Identifies the constants that define the properties of a variable.

Classes

Interfaces

Structures

Delegates

Enumerations

See Also