Creating a host application for the .NET Common Language Runtime.

// SimpleCLRHost.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <atlbase.h>
#include <mscoree.h>

#pragma message("@@--Run BuildManaged.Bat to build the HelloMsgBox.dll(It copies the dll to the debug directory) and then run this sample--@@" )

#import "C:\\WINNT\\Microsoft.NET\\Framework\\v1.0.2914\\Mscorlib.tlb" raw_interfaces_only	

using namespace mscorlib;

int main(int argc, char* argv[])
{
	CComPtr<ICorRuntimeHost>	spRuntimeHost;
	CComPtr<_AppDomain>			spDefAppDomain;
	
	//Retrieve a pointer to the ICorRuntimeHost interface
	HRESULT hr = CorBindToRuntimeEx(
											 NULL,	//Retrieve latest version by default
											 L"wks",	//Request a WorkStation build of the CLR
											 STARTUP_LOADER_OPTIMIZATION_SINGLE_DOMAIN | STARTUP_CONCURRENT_GC, 
											 CLSID_CorRuntimeHost,
											 IID_ICorRuntimeHost,
											 (void**)&spRuntimeHost
											 );

	if (FAILED(hr)) return hr;

	//Start the CLR
	hr = spRuntimeHost->Start();

	CComPtr<IUnknown> pUnk;
	//Retrieve the IUnknown default AppDomain
	hr = spRuntimeHost->GetDefaultDomain(&pUnk);
	if (FAILED(hr)) return hr;

	hr = pUnk->QueryInterface(&spDefAppDomain.p);
	if (FAILED(hr)) return hr;

	CComPtr<_ObjectHandle> spObjectHandle;

	//Creates an instance of the type specified in the Assembly
	hr = spDefAppDomain->CreateInstance(
													_bstr_t("HelloMsgBox"), 
													_bstr_t("Ranjeet.SimpleCLRHost.HelloHostDemo"),
													&spObjectHandle
													);
	if (FAILED(hr)) return hr;

	CComVariant VntUnwrapped;
	hr = spObjectHandle->Unwrap(&VntUnwrapped);
	if (FAILED(hr)) return hr;

	//We know our .NET component exposes IDispatch
	if (VntUnwrapped.vt != VT_DISPATCH)	return E_FAIL;

	CComPtr<IDispatch> pDisp;
	pDisp = VntUnwrapped.pdispVal;
	
	OLECHAR FAR* szMember = L"Hi";
	DISPID dispid;
	DISPPARAMS dispparamsNoArgs = {NULL, NULL, 0, 0};

	//Retrieve the DISPID
	pDisp->GetIDsOfNames (
								IID_NULL, 
								&szMember,
								1,
								LOCALE_SYSTEM_DEFAULT,
								&dispid
								);

	//Invoke the method on the Dispatch Interface
	pDisp->Invoke (
					  dispid,
					  IID_NULL,
					  LOCALE_SYSTEM_DEFAULT,
					  DISPATCH_METHOD,
					  &dispparamsNoArgs,
					  NULL,
					  NULL,
					  NULL
					  );

	spRuntimeHost->Stop();

	return 0;
}