ComImportAttribute, classe

using System;
using System.Runtime.InteropServices;

namespace MyModule
{
	// If you do not have a type library for an interface
	// you can redeclare it using ComImportAttribute.

	// This is how the interface would look in an idl file.

	//[
	//object,
	//uuid("73EB4AF8-BE9C-4b49-B3A4-24F4FF657B26"),
	//dual,	helpstring("IMyStorage Interface"),
	//pointer_default(unique)
	//]
	//interface IMyStorage : IDispatch
	//{
	//	[id(1)]
	//	HRESULT GetItem([in] BSTR bstrName, [out, retval] IDispatch ** ppItem);
	//	[id(2)]
	//	HRESULT GetItems([in] BSTR bstrLocation, [out] SAFEARRAY(VARIANT)* pItems);
	//	[id(3)]
	//	HRESULT GetItemDescriptions([in] BSTR bstrLocation, [out] SAFEARRAY(VARIANT) ** ppItems);
	//	[id(4), propget]
	//	HRESULT get_IsEmpty([out, retval] BOOL * pfEmpty);
	//};

	// This is the managed declaration.

	[ComImport]
	[Guid("73EB4AF8-BE9C-4b49-B3A4-24F4FF657B26")]
	public interface IMyStorage  
	{
		[DispId(1)]
		[return : MarshalAs( UnmanagedType.Interface )]
		Object GetItem( [In, MarshalAs( UnmanagedType.BStr )] String bstrName );

		[DispId(2)]
		void GetItems( [In, MarshalAs( UnmanagedType.BStr )] String bstrLocation, 
			[Out, MarshalAs( UnmanagedType.SafeArray, 
					  SafeArraySubType = VarEnum.VT_VARIANT )] out Object[] Items );


		[DispId(3)]
		void GetItemDescriptions( [In] String bstrLocation, 
			[In, Out, MarshalAs( UnmanagedType.SafeArray )] ref Object[] varDescriptions );

		bool IsEmpty 
		{
			[DispId(4)]
			[return : MarshalAs( UnmanagedType.VariantBool )]
			get;
		}
	}
}