How to load & call a VBScript function from within C++?

Question

We have customers asking for VBScript functions to be called when particular actions occur within our product. I\'ve been trying to research the Windows Scripting technologi

Answer 1

I've put together a "Hello World" IActiveScript C++ ATL console application that:

• Define CSimpleScriptSite class
  • Implement IActiveScriptSite interface (mandatory)
  • Implement IActiveScriptSiteWindow interface (optional)
  • Minimum implementation with most functions implemented with a dummy stub
  • Has no error handling. Consult MSDN IActiveScriptError.
• Use CoCreateInstance a new IActiveSite object
  • Create instances of both VBScript and JScript
  • Link the IActiveSite to IActiveScriptSite using IActiveSite::SetScriptSite
  • Call QueryInterface to get an IActiveScriptParse interface
  • Use IActiveScriptParse to execute VBScript or JScript code
• The sample:
  • Evaluates an expression in JScript
  • Evaluates an expression in VBScript
  • Runs a command in VBScript

Code:

#include "stdafx.h"
#include 
#include 

class CSimpleScriptSite :
    public IActiveScriptSite,
    public IActiveScriptSiteWindow
{
public:
    CSimpleScriptSite() : m_cRefCount(1), m_hWnd(NULL) { }

    // IUnknown

    STDMETHOD_(ULONG, AddRef)();
    STDMETHOD_(ULONG, Release)();
    STDMETHOD(QueryInterface)(REFIID riid, void **ppvObject);

    // IActiveScriptSite

    STDMETHOD(GetLCID)(LCID *plcid){ *plcid = 0; return S_OK; }
    STDMETHOD(GetItemInfo)(LPCOLESTR pstrName, DWORD dwReturnMask, IUnknown **ppiunkItem, ITypeInfo **ppti) { return TYPE_E_ELEMENTNOTFOUND; }
    STDMETHOD(GetDocVersionString)(BSTR *pbstrVersion) { *pbstrVersion = SysAllocString(L"1.0"); return S_OK; }
    STDMETHOD(OnScriptTerminate)(const VARIANT *pvarResult, const EXCEPINFO *pexcepinfo) { return S_OK; }
    STDMETHOD(OnStateChange)(SCRIPTSTATE ssScriptState) { return S_OK; }
    STDMETHOD(OnScriptError)(IActiveScriptError *pIActiveScriptError) { return S_OK; }
    STDMETHOD(OnEnterScript)(void) { return S_OK; }
    STDMETHOD(OnLeaveScript)(void) { return S_OK; }

    // IActiveScriptSiteWindow

    STDMETHOD(GetWindow)(HWND *phWnd) { *phWnd = m_hWnd; return S_OK; }
    STDMETHOD(EnableModeless)(BOOL fEnable) { return S_OK; }

    // Miscellaneous

    HRESULT SetWindow(HWND hWnd) { m_hWnd = hWnd; return S_OK; }

public:
    LONG m_cRefCount;
    HWND m_hWnd;
};

STDMETHODIMP_(ULONG) CSimpleScriptSite::AddRef()
{
    return InterlockedIncrement(&m_cRefCount);
}

STDMETHODIMP_(ULONG) CSimpleScriptSite::Release()
{
    if (!InterlockedDecrement(&m_cRefCount))
    {
        delete this;
        return 0;
    }
    return m_cRefCount;
}

STDMETHODIMP CSimpleScriptSite::QueryInterface(REFIID riid, void **ppvObject)
{
    if (riid == IID_IUnknown || riid == IID_IActiveScriptSiteWindow)
    {
        *ppvObject = (IActiveScriptSiteWindow *) this;
        AddRef();
        return NOERROR;
    }
    if (riid == IID_IActiveScriptSite)
    {
        *ppvObject = (IActiveScriptSite *) this;
        AddRef();
        return NOERROR;
    }
    return E_NOINTERFACE;
}

int _tmain(int argc, _TCHAR* argv[])
{
    HRESULT hr = S_OK;
    hr = CoInitializeEx(NULL, COINIT_MULTITHREADED);

    // Initialize
    CSimpleScriptSite* pScriptSite = new CSimpleScriptSite();
    CComPtr spJScript;
    CComPtr spJScriptParse;
    hr = spJScript.CoCreateInstance(OLESTR("JScript"));
    hr = spJScript->SetScriptSite(pScriptSite);
    hr = spJScript->QueryInterface(&spJScriptParse);
    hr = spJScriptParse->InitNew();
    CComPtr spVBScript;
    CComPtr spVBScriptParse;
    hr = spVBScript.CoCreateInstance(OLESTR("VBScript"));
    hr = spVBScript->SetScriptSite(pScriptSite);
    hr = spVBScript->QueryInterface(&spVBScriptParse);
    hr = spVBScriptParse->InitNew();

    // Run some scripts
    CComVariant result;
    EXCEPINFO ei = { };
    hr = spJScriptParse->ParseScriptText(OLESTR("(new Date()).getTime()"), NULL, NULL, NULL, 0, 0, SCRIPTTEXT_ISEXPRESSION, &result, &ei);
    hr = spVBScriptParse->ParseScriptText(OLESTR("Now"), NULL, NULL, NULL, 0, 0, SCRIPTTEXT_ISEXPRESSION, &result, &ei);
    hr = spVBScriptParse->ParseScriptText(OLESTR("MsgBox \"Hello World! The current time is: \" & Now"), NULL, NULL, NULL, 0, 0, 0, &result, &ei);

    // Cleanup
    spVBScriptParse = NULL;
    spVBScript = NULL;
    spJScriptParse = NULL;
    spJScript = NULL;
    pScriptSite->Release();
    pScriptSite = NULL;

    ::CoUninitialize();
    return 0;
}

A version of the above code can be found here:

• https://github.com/stephenquan/RunScriptDemo