Алекс Jenter - Программирование на Visual C++. Архив рассылки

Атрибут MarshalAs задает правила передачи параметров, наиболее часто он используется в следующих видах:

• MarshalAs(UnmanagedType.LPWStr)– Unicode-строка. Память под строку распределяется и освобождается через системные функции.

• MarshalAs(UnmanagedType.LPArray, SizeParamIndex=n)– передается одномерный массив, размер массива задается параметром с номером n, нумерация параметров начинается с нуля.

• MarshalAs(UnmanagedType.Interface)– передается COM интерфейс.

Примеры интерфейсов

IDL

[object, uuid(0002E000-0000-0000-C000-000000000046), pointer_default(unique)]

interface IEnumGUID : IUnknown {

HRESULT Next([in] ULONG celt,

[out, size_is(celt), length_is(*pceltFetched)] GUID *rgelt,

[out] ULONG *pceltFetched);

HRESULT Skip([in] ULONG celt);

HRESULT Reset();

HRESULT Clone([out] IEnumGUID **ppenum);

}

[object, uuid(0002E011-0000-0000-C000-000000000046), pointer_default(unique)]

interface IEnumCATEGORYINFO : IUnknown {

HRESULT Next([in] ULONG celt,

[out, size_is(celt), length_is(*pceltFetched)] CATEGORYINFO *rgelt,

[out] ULONG *pceltFetched);

HRESULT Skip([in] ULONG celt);

HRESULT Reset();

HRESULT Clone([out] IEnumCATEGORYINFO **ppenum);

}

[object, uuid(0002E013-0000-0000-C000-000000000046), pointer_default(unique)]

interface ICatInformation : IUnknown {

HRESULT EnumCategories([in] LCID lcid,

[out] IEnumCATEGORYINFO** ppenumCategoryInfo);

HRESULT GetCategoryDesc([in] REFCATID rcatid,

[in] LCID lcid,

[out] LPWSTR* pszDesc);

[local]

HRESULT EnumClassesOfCategories([in] ULONG cImplemented,

[in,size_is(cImplemented)] CATID rgcatidImpl[],

[in] ULONG cRequired,

[in,size_is(cRequired)] CATID rgcatidReq[],

[out] IEnumCLSID** ppenumClsid);

[call_as(EnumClassesOfCategories)]

HRESULT RemoteEnumClassesOfCategories([in] ULONG cImplemented,

[in,unique,size_is(cImplemented)] CATID rgcatidImpl[],

[in] ULONG cRequired,

[in,unique,size_is(cRequired)] CATID rgcatidReq[],

[out] IEnumCLSID** ppenumClsid);

[local]

HRESULT IsClassOfCategories([in] REFCLSID rclsid,

[in] ULONG cImplemented,

[in,size_is(cImplemented)] CATID rgcatidImpl[],

[in] ULONG cRequired,

[in,size_is(cRequired)] CATID rgcatidReq[]);

[call_as(IsClassOfCategories)]

HRESULT RemoteIsClassOfCategories([in] REFCLSID rclsid,

[in] ULONG cImplemented,

[in,unique,size_is(cImplemented)] CATID rgcatidImpl[],

[in] ULONG cRequired,

[in,unique,size_is(cRequired)] CATID rgcatidReq[]);

HRESULT EnumImplCategoriesOfClass([in] REFCLSID rclsid,

[out] IEnumCATID** ppenumCatid);

HRESULT EnumReqCategoriesOfClass([in] REFCLSID rclsid,

[out] IEnumCATID** ppenumCatid);

}

C#

[ComImport, Guid("0002E000-0000-0000-C000-000000000046"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]

public interface IEnumGUID {

[PreserveSig()]

int Next([In] uint celt,

[Out, MarshalAs(UnmanagedType.LPArray, SizeParamIndex=0)] Guid[] rgelt,

[Out] out uint pceltFetched);

[PreserveSig()]

int Skip([In] uint celt);

void Reset();

[return : MarshalAs(UnmanagedType.Interface)]

IEnumGUID Clone();

};

[ComImport, Guid("0002E011-0000-0000-C000-000000000046"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]

public interface IEnumCATEGORYINFO {

[PreserveSig()]

int Next([In] uint celt,

[Out, MarshalAs(UnmanagedType.LPArray, SizeParamIndex=0)] CATEGORYINFO[] rgelt,

[Out] out uint pceltFetched);

[PreserveSig()]

int Skip([In] uint celt);

void Reset();

[return : MarshalAs(UnmanagedType.Interface)]

IEnumCATEGORYINFO Clone();

};

[ComImport, Guid("0002E013-0000-0000-C000-000000000046"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]

public interface ICatInformation {

[return : MarshalAs(UnmanagedType.Interface)]

IEnumCATEGORYINFO EnumCategories([In] uint lcid);

[return : MarshalAs(UnmanagedType.LPWStr)]

String GetCategoryDesc([In] ref Guid rcatid, [In] uint lcid);

[return : MarshalAs(UnmanagedType.Interface)]

IEnumGUID EnumClassesOfCategories([In] uint cImplemented,

[In, MarshalAs(UnmanagedType.LPArray, SizeParamIndex=0)] Guid[] rgcatidImpl,

[In] uint cRequired,

[In, MarshalAs(UnmanagedType.LPArray, SizeParamIndex=2)] Guid[] rgcatidReq);

[return : MarshalAs(UnmanagedType.Interface)]

IEnumGUID RemoteEnumClassesOfCategories([In] uint cImplemented,

[In, MarshalAs(UnmanagedType.LPArray, SizeParamIndex=0)] Guid[] rgcatidImpl,

[In] uint cRequired,

[In, MarshalAs(UnmanagedType.LPArray, SizeParamIndex=2)] Guid[] rgcatidReq);

[PreserveSig()]

int IsClassOfCategories([In] ref Guid rclsid,

[In] uint cImplemented,

[In, MarshalAs(UnmanagedType.LPArray, SizeParamIndex=0)] Guid[] rgcatidImpl,

[In] uint cRequired,

[In, MarshalAs(UnmanagedType.LPArray, SizeParamIndex=2)] Guid[] rgcatidReq);

[PreserveSig()]

int RemoteIsClassOfCategories([In] ref Guid rclsid,

[In] uint cImplemented,

[In, MarshalAs(UnmanagedType.LPArray, SizeParamIndex=0)] Guid[] rgcatidImpl,

[In] uint cRequired,

[In, MarshalAs(UnmanagedType.LPArray, SizeParamIndex=2)] Guid[] rgcatidReq);

[return : MarshalAs(UnmanagedType.Interface)]

IEnumGUID EnumImplCategoriesOfClass([In] ref Guid rclsid);

[return : MarshalAs(UnmanagedType.Interface)]

IEnumGUID EnumReqCategoriesOfClass([In] ref Guid rclsid);

};

Для описания классов также используются атрибуты ComImport и Guid. Классы с атрибутом ComImport не могут иметь никаких данных и методов.

IDL

Описание отсутствует

C#

[ComImport, Guid("0002E005-0000-0000-C000-000000000046")]