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<HTML><HEAD>   <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">   <META NAME="Author" CONTENT="V. Rama Krishna ">   <TITLE>ActiveX script hosting - 2</TITLE></HEAD><body background="../fancyhome/back.gif" bgcolor="#FFFFFF" link="#B50029" vlink="#8E2323" alink="#FF0000" bgproperties="fixed"><table WIDTH="100%"><tr WIDTH="100%"><td align=center><!--#exec cgi="/cgi/ads.cgi"--><td></tr></table><CENTER><H3><FONT COLOR="#AOAO99">ActiveX script hosting - 2</FONT></H3></CENTER><CENTER><H3><HR></H3></CENTER>This article was contributed by <A HREF="mailto:andrew@kms.donetsk.ua">Andrew Garbuzov</A>.<!--  --><p>This code represents one of my current experiments with active scripthosting. I am not sure if the code will be useful for you, i am not evensure if the code will be useful for me either. The explanation of myuncertainty is in the readme.txt file, packed along with the project.I have prepared this article not just to show you an example, but mostlyto ask you some questions being in hope for receiving some answers.<p>In this experiment i have tried to make a program that would use theMicrosoft Forms 2.0 designer, along with abilities to control the form,created by the designer, with programs written in VBScript.<p>When you run the program open the file "TestForm.frm". This is anexample of form. You can use the menu item "View|Design mode" toedit form's design, and the menu item "View|Edit script" to seethe VBScript source of the form.<p>I have tested the program under NT 4.0 and Windows 95 (4.00.950).Under NT4 everything goes ok, but under Windows 95 i see messagesduring execution in the debug window telling:<p>First-chance exception in MsForm.exe (GDI32.DLL): 0xC0000005: Access Violation.<p>When i try to exit, the program causes a GPF in OLEAUTO.DLL and dies.I do not know so far what is wrong with my code.<p>I am not going to describe how to create active script hosts. There aresome articles in Internet concerning the topic. I have even tried todescribe it myself. Here i will try to explain how to add the MSForm designerto your MFC project, and how to connect the designer to the scripting engine.<p>If you run the "OLE-COM Object Viewer" program and select the menu item"File|View TypeLib..." and select the "FM20.DLL" file locatedin your Windows System folder, you will see the coclass "UserForm".Observe that the interface to the "UserForm" coclass (_UserForm) has beeninherited form the interface to the "Frame" colass (IOptionFrame). Havingnoticed this feature, i have made some steps for creating an MFC wrapperclass for MSForm designer in my project.<ol>  <li> In the Developer studio selected  the menu item"Project|Add to project|Components and controls".  <li> In the "Registered ActiveX Controls" folder selected the"Microsoft Forms 2.0 Frame" control. The MSDEV created some wrapperMFC classes to work with Microsoft controls.  <li>In all created files replaced the word "OptionFrame" with "UserForm".I have changed the names of the "optionframe.cpp" and "optionframe.h" filesaccordingly.  <li> Modified the CUserForm::Create functions with new ones which useCLSID of the "UserForm" coclass.  <li> Manualy implemented the hidden "DesignMode" property of the form.</ol><p>Thus i have created the MFC wrapper class for MSForm control. The nameof the wrapper class is CUserForm.<p>My next step was creating the four classes CMsFormDoc, CMsFormView,CVbscriptView and CMSFormFrame.<p>The CMsFormDoc object almost does nothing except of serializingand providing links between FormView and VbscriptView objects.<p>The CVbscriptView is a simple editor to edit a vbscript code fora form.<p>The CMSFormFrame provides a way of containing two views - the MsFormView,and the CVbscriptView together in a single frame.<p>The CMsFormView object carries on and controls a CUserForm object andon user requests switches on and off the design mode of the form.<p>Take a look at the CMsFormView::GetUserFormUnknown() function. If youwant to obtain the IUnknown interface to an object created by CWnd::CreateControl function, you will not be able to get it by callingthe GetIDispatch function. CWnd object incapsulates the OLE controlcontainer features by some undocumented classes which are definedin the <occimpl.h> header file located in the MFC source folder.<pre><tt><font COLOR="#990000">//The code to obtain the IUnknown interface to the controlIUnknown* CMsFormView::GetUserFormUnknown(){	IUnknown* pUnk=m_UserForm.GetControlUnknown();	return pUnk;}</font></tt></pre><p>The two functions - CMsFormView::WriteDesignToFile(LPCTSTR lpstrFileName)and CMsFormView::ReadDesignFromFile(LPCTSTR lpstrFileName) implement theform control contents writing to and reading from a temporary file.<p>The CMsFormDoc::Serialize(CArchive&amp; ar) function use these functionsto store and load the design information.<p>Connecting the form with the scripting engine is not difficult. In thisexperiment i used the CScriptEngine class provided by .... I have made the CMsFormScriptEngine class derived form CScriptEngine topass the information needed from the form to the scripting engine. Aninstance of the CMsFormScriptEngine is a part of CMsFormView class.<pre><tt><font COLOR="#990000">class CMsFormView : public CView{	.....	CUserForm				m_UserForm;	CMsFormScriptEngine		m_ScriptEngine;};</font></tt></pre><p>The CMsFormView::Run function feeds the scripting engine with nameditems, script code, and switches it to the "connected" state. Herethere is a problem. A scripting engine can process events fromobjects, referenced by the AddNamedItem function, and their properties- objects which can source events by themselves. The information aboutobject's properties the scripting engine obtains from the type library.Since form designer has undefined set of properties, at themoment of compilation of the project, the type library must becreated dynamicaly. Moreover, the IDispatch interface to such an objectmust support dynamic properties. The example of creating such an objectand such a typelib is the "Axscript" project, located in the ActiveX SDKexamples folder. I am not familiar with the ICreateTypeLib, ICreateTypeInfoand IProvideMultipleInfo interfaces. I failed to find any documentationto these interfaces. When i tried to repeat the code, shown in the example,whith MFC, i had not achieved the results i wanted. <p>I have solved the problem by adding references to all the controls in theform to the scripting engine. Observe that the reference to the "Form"named item is added with the SCRIPTITEM_GLOBALMEMBERS. All named items areadded with the SCRIPTITEM_ISVISIBLE|SCRIPTITEM_ISSOURCE flags.<pre><tt><font COLOR="#990000">void CMsFormView::Run(){	if(!m_ScriptEngine.IsCreated())		m_ScriptEngine.Create(CLSID_VBScript);	else	{		SCRIPTSTATE ss=m_ScriptEngine.GetScriptState();		if(ss==SCRIPTSTATE_CONNECTED)			return;	}	CString strScript=GetDocument()-&gt;GetScriptText();	if(!strScript.IsEmpty() &amp;&amp; m_UserForm.GetDesignMode()!=-1)	{		HRESULT		hr;				USES_CONVERSION;		LPCOLESTR	pstrItemName = T2COLE(_T("Form"));		LPCOLESTR	pstrCode = T2COLE(strScript);		EXCEPINFO   ei;						hr=m_ScriptEngine.AddNamedItem(pstrItemName, SCRIPTITEM_ISVISIBLE|SCRIPTITEM_ISSOURCE|SCRIPTITEM_GLOBALMEMBERS);		if(FAILED(hr))		{			AfxMessageBox(_T("AddNamedItem failed. Item name: &lt;Form&gt;."));			return;		}				//Adding form controls		for(long i=0; i&lt;m_UserForm.GetControls().GetCount(); i++)		{			CString strControlName=m_UserForm.GetControls()._GetItemByIndex(i).GetName();			LPCOLESTR	pstrControlName;			pstrControlName = T2COLE(strControlName);			hr=m_ScriptEngine.AddNamedItem(pstrControlName,SCRIPTITEM_ISVISIBLE | SCRIPTITEM_ISSOURCE);			if(FAILED(hr))			{				CString strError=_T("AddNamedItem failed. Item name: &lt;");				strError+=strControlName+_T("&gt;");				AfxMessageBox(strError);				return;			}		}					if(SUCCEEDED(m_ScriptEngine.ParseScriptText(pstrCode, pstrItemName, NULL, NULL, 0, 0, 0L, NULL, &amp;ei)))			m_ScriptEngine.Run();		else			AfxMessageBox(_T("Can't parse script text"));	}}</font></tt></pre><p>The interfaces to the named items are obtained by the scripting engine in theCMsFormScriptEngine::OnGetItemInfo function. The CMsFormScriptEngine objecthas a back pointer (m_pView) to the CMsFormView object in which it iscontained. The technique of obtaining the class information of an objecti have seen in several examples. I just do not understand why theIProvideClassInfo interface to the object is not released. When i triedto release the interface, my program caused a GPF.<pre><tt><font COLOR="#990000">IProvideClassInfo* pProvideClassInfo = NULL;hr = pUnk-&gt;QueryInterface(IID_IProvideClassInfo, (void**)&amp;pProvideClassInfo);			// if the object supports IprovideClassInfo ...if (SUCCEEDED(hr) &amp;&amp; pProvideClassInfo != NULL){	hr = pProvideClassInfo-&gt;GetClassInfo(ppTypeInfo);		//The pProvideClassInfo-&gt;Release() should not be called. Why?}/////////////////////////////////////////////////////////////////////////////// CMsFormScriptEngine message handlersHRESULT CMsFormScriptEngine::OnGetItemInfo(		/* [in] */ LPCOLESTR   pstrName,		/* [in] */ DWORD       dwReturnMask,		/* [out]*/ IUnknown**  ppUnknownItem,		/* [out]*/ ITypeInfo** ppTypeInfo){	USES_CONVERSION;	HRESULT hr=CScriptEngine::OnGetItemInfo(pstrName,dwReturnMask,ppUnknownItem,ppTypeInfo);	if(!m_pView)		return hr;	hr=TYPE_E_ELEMENTNOTFOUND;	if (dwReturnMask &amp; SCRIPTINFO_ITYPEINFO)	{		if (!ppTypeInfo)			return E_INVALIDARG;		*ppTypeInfo = NULL;	}	if (dwReturnMask &amp; SCRIPTINFO_IUNKNOWN)	{		if (!ppUnknownItem)			return E_INVALIDARG;		*ppUnknownItem = NULL;	}	TCHAR* lpstrItemName=OLE2T(pstrName);	IUnknown* pUnk=0;	if(!_tcscmp(_T("Form"), lpstrItemName))	{		pUnk=m_pView-&gt;GetUserFormUnknown();	}	else	{		CControls Controls=m_pView-&gt;m_UserForm.GetControls();		for(long i=0; i&lt;Controls.GetCount(); i++)		{			CControl C=Controls._GetItemByIndex(i);			CString strControlName=C.GetName();						if(strControlName==lpstrItemName)			{				pUnk=C.m_lpDispatch;				break;			}						}	}	if(pUnk)	{		if (dwReturnMask &amp; SCRIPTINFO_ITYPEINFO)		{			IProvideClassInfo* pProvideClassInfo = NULL;			hr = pUnk-&gt;QueryInterface(IID_IProvideClassInfo, (void**)&amp;pProvideClassInfo);						// if the object supports IprovideClassInfo ...			if (SUCCEEDED(hr) &amp;&amp; pProvideClassInfo != NULL)			{				hr = pProvideClassInfo-&gt;GetClassInfo(ppTypeInfo);			}		}		if (dwReturnMask &amp; SCRIPTINFO_IUNKNOWN)		{			pUnk-&gt;AddRef();			*ppUnknownItem=pUnk;			hr=S_OK;		}	}	return hr;}</font></tt></pre><p>To enable standard keyboard handling by forms, i have implemented theCMsForm::PreTranslateMessage function. It is alomost the same asCFormView::PreTranslateMessage, but i had some problems with typingin text boxes, so i had to make some alterations.<pre><tt><font COLOR="#990000">BOOL CMsFormView::PreTranslateMessage(MSG* pMsg) {	// TODO: Add your specialized code here and/or call the base class	// allow tooltip messages to be filtered	if (CView::PreTranslateMessage(pMsg))		return TRUE;	// don't translate dialog messages when in Shift+F1 help mode	CFrameWnd* pFrameWnd = GetTopLevelFrame();	if (pFrameWnd != NULL &amp;&amp; pFrameWnd-&gt;m_bHelpMode)		return FALSE;	// since 'IsDialogMessage' will eat frame window accelerators,	//   we call all frame windows' PreTranslateMessage first	pFrameWnd = GetParentFrame();   // start with first parent frame	while (pFrameWnd != NULL)	{		// allow owner &amp; frames to translate before IsDialogMessage does		if (pFrameWnd-&gt;PreTranslateMessage(pMsg))			return TRUE;		// try parent frames until there are no parent frames		pFrameWnd = pFrameWnd-&gt;GetParentFrame();	}		//To allow typing in text boxes	if (pMsg-&gt;message == WM_CHAR)		return FALSE;	// filter both messages to dialog and from children	return PreTranslateInput(pMsg);}</font></tt></pre><p>That's all. If you have any information concerning the ActiveX scripthosting technology or dynamic properties support, please send me a message.

<P>Useful References :-<OL>
<li><A HREF="http://support.microsoft.com/support/downloads/LNP413.asp?PR=ALL&FR=0&M=S&">Microsoft Support - ActiveX Scripting Download Site</A></li><li><A HREF="http://www.vcdj.com/vcdj/may97/axscrip.htm">Visual C++ Developers's Journal May 97 - Steve Wampler's article on Active X Script Hosting</A></li>
</OL><P><A HREF="msform.exe">Download file</A>. This is a compressed executable.<!-- end --><P>Posted on: April 15, 98.<P><HR><TABLE BORDER=0 WIDTH="100%" ><TR><TD WIDTH="33%"><FONT SIZE=-1><A HREF="http://www.codeguru.com">Goto HomePage</A></FONT></TD><TD WIDTH="33%"> <CENTER><FONT SIZE=-2>&copy; 1998 Zafir Anjum</FONT>&nbsp;</CENTER></TD><TD WIDTH="34%"><DIV ALIGN=right><FONT SIZE=-1>Contact me: <A HREF="mailto:zafir@home.com">zafir@home.com</A>&nbsp;</FONT></DIV></TD></TR></TABLE></BODY></HTML>
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