如何使用com组件

这里有篇介绍的很详细的文章：https://www.codeproject.com/Articles/633/Introduction-to-COM-What-It-Is-and-How-to-Use-It

 

这是我根据文章写的demo，能够成功实现

#define WIN32_LEAN_AND_MEAN
#include <Windows.h>
#include <WinInet.h> // Shell object uses INTERNET_MAX_URL_LENGTH (go figure)
#if _MSC_VER < 1400
#define _WIN32_IE 0x0400
#endif
#include <atlbase.h> // ATL smart pointers
#include <shlguid.h> // shell GUIDs
#include <shlobj.h>  // IActiveDesktop
#include <string>
#include <iostream>

struct __declspec(uuid("F490EB00-1240-11D1-9888-006097DEACF9")) IActiveDesktop;

using namespace std;

LPWSTR ConvertToLPWSTR(const std::string& s)
{
	LPWSTR ws = new wchar_t[s.size() + 1]; // +1 for zero at the end
	copy(s.begin(), s.end(), ws);
	ws[s.size()] = 0; // zero at the end
	return ws;
}

int main()
{
	WCHAR   wszWallpaper[MAX_PATH];
	string strPath;
	HRESULT hr;
	IActiveDesktop* pIAD;

	// 1. Initialize the COM library (make Windows load the DLLs). Normally you would
	// call this in your InitInstance() or other startup code.  In MFC apps, use
	//  AfxOleInit() instead.</FONT>
	CoInitialize(NULL);

	//<FONT COLOR = "#009900">// 2. Create a COM object, using the Active Desktop coclass provided by the shell.
	// The 4th parameter tells COM what interface we want (IActiveDesktop).</FONT>
	hr = CoCreateInstance(CLSID_ActiveDesktop,
		NULL,
		CLSCTX_INPROC_SERVER,
		IID_IActiveDesktop,
		(void**)&pIAD);

	if (SUCCEEDED(hr))
	{
		//		<FONT COLOR = "#009900">// 3. If the COM object was created, call its GetWallpaper() method.</FONT>
		hr = pIAD->GetWallpaper(wszWallpaper, MAX_PATH, 0);

		if (SUCCEEDED(hr))
		{
			// 4. If GetWallpaper() succeeded, print the filename it returned.
			// Note that I'm using wcout to display the Unicode string wszWallpaper.
			// wcout is the Unicode equivalent of cout.
			wcout << L"Wallpaper path is:\n    " << wszWallpaper << endl << endl;
		}
		else
		{
			cout << _T("GetWallpaper() failed.") << endl << endl;
		}

		// 5. Release the interface.
		pIAD->Release();
	}
	else
	{
		cout << _T("CoCreateInstance() failed.") << endl << endl;
	}

	// 6. Uninit the COM library.  In MFC apps, this is not necessary since MFC does
	// it for us.
	CoUninitialize();


///////////////////////////////////////////////////////////////////////////////////////

	wstring ws(wszWallpaper);
	string       sWallpaper(ws.begin(), ws.end());  // Convert the wallpaper path to ANSI
	IShellLink*   pISL;
	IPersistFile* pIPF;

	// 1. Initialize the COM library (make Windows load the DLLs). Normally you would
	// call this in your InitInstance() or other startup code.  In MFC apps, use
	// AfxOleInit() instead.
	CoInitialize(NULL);

//	2. Create a COM object, using the Shell Link coclass provided by the shell.
		// The 4th parameter tells COM what interface we want (IShellLink).
		hr = CoCreateInstance(CLSID_ShellLink,
			NULL,
			CLSCTX_INPROC_SERVER,
			IID_IShellLink,
			(void**)&pISL);

	if (SUCCEEDED(hr))
	{
		// 3. Set the path of the shortcut's target (the wallpaper file).
	
		LPWSTR ws = ConvertToLPWSTR(sWallpaper);

		hr = pISL->SetPath((LPCSTR)ws);

		if (SUCCEEDED(hr))
		{
			// 4. Get a second interface (IPersistFile) from the COM object.
			hr = pISL->QueryInterface(IID_IPersistFile, (void**)&pIPF);

			if (SUCCEEDED(hr))
			{
				// 5. Call the Save() method to save the shortcut to a file.  The
				// first parameter is a Unicode string.
				hr = pIPF->Save(L"C:\\Users\\strives\\Desktop\\wallpaper.lnk", FALSE);

				// 6a. Release the IPersistFile interface.
				pIPF->Release();
			}
		}

		// 6b. Release the IShellLink interface.
		pISL->Release();
	}

	// Printing of error messages omitted here.

	// 7. Uninit the COM library.  In MFC apps, this is not necessary since MFC
	// does it for us.
	CoUninitialize();
}