/Visual Studio 2008/CppCOMClient/ImportDirective.cpp

/****************************** Module Header ******************************\

* Module Name:  ImportDirective.cpp

* Project:      CppCOMClient

* Copyright (c) Microsoft Corporation.

* 

* #import (http://msdn.microsoft.com/en-us/library/8etzzkb6.aspx), a new 

* directive that became available with Visual C++ 5.0, creates VC++ "smart 

* pointers" from a specified type library. It is very powerful, but often not 

* recommended because of reference-counting problems that typically occur when 

* used with the Microsoft Office applications. Unlike the direct API approach 

* in RawAPI.h/cpp, smart pointers enable us to benefit from the type info to 

* early/late bind the object. #import takes care of adding the messy guids to 

* the project and the COM APIs are encapsulated in custom classes that the 

* #import directive generates.

* 

* The differences between early binding and late binding via smart pointers:

* 

* Smart pointers make creating an object that supports early binding easy, so 

* does it make creating a late bound object. The only difference between early 

* binding and late binding via smart pointer is the .tlh and .tli files 

* generated by the #import directive. If the target object supports early 

* binding, the .tlh and .tli files will make use of the custom interface (not 

* IDispatch) to call the target property/method directly. If the target COM 

* object only support late binding, the smart pointer takes care of converting 

* your method calls into GetIDsOfNames()s and Invoke()s of the IDispatch 

* interface.

* 

* References

*  http://support.microsoft.com/kb/169496

* 

* This source is subject to the Microsoft Public License.

* See http://www.microsoft.com/opensource/licenses.mspx#Ms-PL.

* All other rights reserved.

* 

* THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, 

* EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED 

* WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.

\***************************************************************************/



#pragma region Includes

#include <stdio.h>

#include "ImportDirective.h"

#pragma endregion





#pragma region Import the type library



// Importing mscorlib.tlb is necessary for .NET components

// see: 

//  http://msdn.microsoft.com/en-us/library/s5628ssw.aspx

#import "mscorlib.tlb" raw_interfaces_only				\

	high_property_prefixes("_get","_put","_putref")		\

	rename("ReportEvent", "InteropServices_ReportEvent")

using namespace mscorlib;



// Option 1) #import the name of a file that contains a type library 

// 

// We can either specify the full path of the tlb/dll/ocx/exe file or add 

// the path of the file to the project's Additional Include Directories 

// setting.

// 

// For .NET components, importing the assembly file (dll/exe) fails because 

// the type library is not embedded in the .NET assemblies. There is a 

// stand-alone tlb file. For native components, the type library is embedded 

// into the executable by default, and we can #import the dll/ocx/exe module 

// directly.



//#import "CSDllCOMServer.tlb" no_namespace named_guids



// Option 2) #import the progid of the component in the type library

// 

// #import-ing the progid only works for native components because .NET 

// components do not register the typelib for its ProgID by default. As an

// evidence, please open the CLSID registry node and check the TypeLib key: 

// HKCR\CLSID\{xxxx}\TypeLib, which is lacked by .NET components.



//#import "progid:CSDllCOMServer.SimpleObject" \

//	no_namespace \

//	named_guids



// Option 3) #import the libid of the type library

// 

// In the type library of CSDllCOMServer, the library ID is

// F0998D9A-0E79-4F67-B944-9E837F479587

// 

//  [uuid(F0998D9A-0E79-4F67-B944-9E837F479587), version(1.0),

//  custom(90883F05-3D28-11D2-8F17-00A0C9A6186D,"CSDllCOMServer,...)] 

//  library CSDllCOMServer { ... } 

// 

// #importing the library ID works for both native an .NET components.



#import "libid:F0998D9A-0E79-4F67-B944-9E837F479587" \

	no_namespace \

	named_guids



#pragma endregion





/*!

 * \brief

 * The definition of ImportCSharpComponent in the header file

 * 

 * \see

 * Separate ImportDirective.h | ImportCSharpComponent

 */

DWORD WINAPI ImportCSharpComponent(LPVOID lpParam)

{

	HRESULT hr = S_OK;



	// Initializes the COM library on the current thread and identifies the

	// concurrency model as single-thread apartment (STA). 

	// [-or-] ::CoInitialize(NULL);

	// [-or-] ::CoCreateInstance(NULL);

	::CoInitializeEx(NULL, COINIT_APARTMENTTHREADED);



	try

	{

        // Create the CSDllCOMServer.SimpleObject COM object using the 

        // #import directive and smart pointers.



        // Option 1) Create the object using the smart pointer's constructor

        // 

        // ISimpleObjectPtr is the original interface name, ISimpleObject, 

        // with a "Ptr" suffix.

        //ISimpleObjectPtr spSimpleObj(

        //	__uuidof(SimpleObject)	// CLSID of the component

        //	);



        // Option 2) Create the object using the smart pointer's function,

        // CreateInstance

        ISimpleObjectPtr spSimpleObj;

        hr = spSimpleObj.CreateInstance(__uuidof(SimpleObject));

        if (FAILED(hr))

        {

            wprintf(L"ISimpleObjectPtr::CreateInstance failed w/err 0x%08lx\n", hr);

            return hr;

        }



        //

        // Consume the properties and the methods of the COM object.

        // 



		// Set the property: FloatProperty.

		{

			wprintf(L"Set FloatProperty = %.2f\n", 1.2f);

			spSimpleObj->FloatProperty = 1.2f;

		}



		// Get the property: FloatProperty.

		{

			wprintf(L"Get FloatProperty = %.2f\n", spSimpleObj->FloatProperty);

		}



		// Call the method: HelloWorld, that returns a BSTR.

		{

			// the _bstr_t object and the underlying BSTR will be cleared 

			// automatically in the destructor when the object is out of 

			// the scope.

			bstr_t bstrResult = spSimpleObj->HelloWorld();

			wprintf(L"Call HelloWorld => %s\n", (PCWSTR)bstrResult);

		}



		// Call the method: GetProcessThreadID, that outputs two DWORDs.

		{

			wprintf(L"The client process and thread: %ld, %ld\n",

				GetCurrentProcessId(), GetCurrentThreadId());

			

			DWORD dwProcessId, dwThreadId;

			spSimpleObj->GetProcessThreadID(&dwProcessId, &dwThreadId);

			wprintf(L"Call GetProcessThreadID => %ld, %ld\n", 

				dwProcessId, dwThreadId);

		}



        // Release the COM objects.

        // Releasing the references is not necessary for the smart pointers

        // spSimpleObj.Release();



        wprintf(L"\n");

	}

	catch (_com_error &err)

	{

		wprintf(L"The server throws the error: %s\n", err.ErrorMessage());

		wprintf(L"Description: %s\n", (PCWSTR) err.Description());

	}



	// Uninitialize COM for this thread

	::CoUninitialize();



	return hr;

}