COMSupport.cpp

#include "COMSupport.h"
#include <stdio.h>

using namespace std;

/*
 * This method comes from MSDN, and its address is:
 * https://support.microsoft.com/en-us/help/216686/how-to-automate-excel-from-c-without-using-mfc-or-import
 */

// AutoWrap() - Automation helper function...如果使用DISPATCH_METHOD,并且带有参数，需要将参数顺序倒过来！
HRESULT AutoWrap(int autoType, VARIANT *pvResult, IDispatch *pDisp, LPOLESTR ptName, int cArgs...) {
	// Begin variable-argument list...
	va_list marker;
	va_start(marker, cArgs);

	if (!pDisp) {
		MessageBox(NULL, "NULL IDispatch passed to AutoWrap()", "Error", 0x10010);
		_exit(0);
	}

	// Variables used...
	DISPPARAMS dp = { NULL, NULL, 0, 0 };
	DISPID dispidNamed = DISPID_PROPERTYPUT;
	DISPID dispID;
	HRESULT hr;
	char buf[200];
	char szName[200];


	// Convert down to ANSI
	WideCharToMultiByte(CP_ACP, 0, ptName, -1, szName, 256, NULL, NULL);

	// Get DISPID for name passed...
	hr = pDisp->GetIDsOfNames(IID_NULL, &ptName, 1, LOCALE_USER_DEFAULT, &dispID);
	if (FAILED(hr)) {
		sprintf(buf, "IDispatch::GetIDsOfNames(\"%s\") failed w/err 0x%08lx", szName, hr);
		MessageBox(NULL, buf, "AutoWrap()", 0x10010);
		_exit(0);
		return hr;
	}

	// Allocate memory for arguments...
	VARIANT *pArgs = new VARIANT[cArgs + 1];
	// Extract arguments...
	for (int i = 0; i<cArgs; i++) {
		pArgs[i] = va_arg(marker, VARIANT);
	}

	// Build DISPPARAMS
	dp.cArgs = cArgs;
	dp.rgvarg = pArgs;

	// Handle special-case for property-puts!
	if (autoType & DISPATCH_PROPERTYPUT) {
		dp.cNamedArgs = 1;
		dp.rgdispidNamedArgs = &dispidNamed;
	}

	// Make the call!
	hr = pDisp->Invoke(dispID, IID_NULL, LOCALE_SYSTEM_DEFAULT, autoType, &dp, pvResult, NULL, NULL);
	if (FAILED(hr)) {
		DWORD dwError = ::GetLastError();


		sprintf(buf, "IDispatch::Invoke(\"%s\"=%08lx) failed w/err 0x%08lx", szName, dispID, hr);
		MessageBox(NULL, buf, "AutoWrap()", 0x10010);
		_exit(0);
		return hr;
	}
	// End variable-argument section...
	va_end(marker);

	delete[] pArgs;

	return hr;
}

// Used to do a simple function mark
void NothingTodo() {

}