How to add support for hosting VBScript to an ATL application

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Article ID: 223139 - View products that this article applies to.
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SUMMARY

You can add VBA-like scripting capability to your ATL application with little overhead, using Microsoft ActiveX Scripting technologies. This article demonstrates how to create a new ATL application, or modify an existing one, that incorporates support for VBScript.

MORE INFORMATION

Follow the steps below to build and run the example:
  1. Create a new ATL COM EXE project called AtlClientApp, or use an existing such project to which you want to add support for hosting VBScript.
  2. Follow the steps described in the following Microsoft Knowledge Base article to add a dialog to your application:
    196135 How to create an automation client project using ATL
  3. Open your dialog in ResourceView, and add an edit-box where the user can type in some VBScript. Right-click on it, choose properties, and make it "Multiline" and "Want return."
  4. Select New ATL Object from the Insert menu. Add a Simple Object named MyObject on the Names tab, and select Support Connection Points on the Attributes tab.
  5. Add a new file called MyScriptSite.h to your application, and paste the following code into it:
       #include <windows.h>
       #include <activscp.h>
    
       class CMyScriptSite : public IActiveScriptSite {
       private:
          ULONG m_dwRef;
       public:
          IUnknown *m_pUnkScriptObject;
          ITypeInfo *m_pTypeInfo;
    
          CMyScriptSite::CMyScriptSite() {
             m_pUnkScriptObject = 0;
             m_pTypeInfo = 0;
             m_dwRef = 1;
          }
    
          // IUnknown methods...
          virtual HRESULT __stdcall QueryInterface(REFIID riid,
             void **ppvObject) {
             *ppvObject = NULL;
             return E_NOTIMPL;
          }
          virtual ULONG _stdcall AddRef(void) {
             return ++m_dwRef;
          }
          virtual ULONG _stdcall Release(void) {
             if(--m_dwRef == 0) return 0;
             return m_dwRef;
          }
    
          // IActiveScriptSite methods...
          virtual HRESULT __stdcall GetLCID(LCID *plcid) {
             return S_OK;
          }
       
          virtual HRESULT __stdcall GetItemInfo(LPCOLESTR pstrName,
             DWORD dwReturnMask, IUnknown **ppunkItem, ITypeInfo **ppti) {
             // Is it expecting an ITypeInfo?
             if(ppti) {
                // Default to NULL.
                *ppti = NULL;
             
                // See if asking about ITypeInfo... 
                if(dwReturnMask & SCRIPTINFO_ITYPEINFO) {
                   *ppti = m_pTypeInfo;
                }
             }
          
             // Is the engine passing an IUnknown buffer?
             if(ppunkItem) {
                // Default to NULL.
                *ppunkItem = NULL;
             
                // Is Script Engine looking for an IUnknown for our object?
                if(dwReturnMask & SCRIPTINFO_IUNKNOWN) {
                   // Check for our object name...
                   if (!_wcsicmp(L"MyObject", pstrName)) {
                      // Provide our object.
                      *ppunkItem = m_pUnkScriptObject;
                      // Addref our object...
                      m_pUnkScriptObject->AddRef();
                   }
                }
             }
          
             return S_OK;
          }
       
          virtual HRESULT __stdcall GetDocVersionString(BSTR *pbstrVersion) {
             return S_OK;
          }
       
          virtual HRESULT __stdcall OnScriptTerminate(
             const VARIANT *pvarResult, const EXCEPINFO *pexcepInfo) {
             return S_OK;
          }
       
          virtual HRESULT __stdcall OnStateChange(SCRIPTSTATE ssScriptState) {
             return S_OK;
          }
       
          virtual HRESULT __stdcall OnScriptError(
             IActiveScriptError *pscriptError) {
             ::MessageBox(NULL, "OnScriptError()", "Error", MB_SETFOREGROUND);     
             return S_OK;
          }
       
          virtual HRESULT __stdcall OnEnterScript(void) {
             return S_OK;
          }
       
          virtual HRESULT __stdcall OnLeaveScript(void) {
             return S_OK;
          }
    
       };
    					
  6. Remove any code you have in your OnOK() dialog button handler, and add the following code:
       // Instantiate script site & objects...
       CMyScriptSite *pMySite = new CMyScriptSite;
       CComObject<CMyObject> *pMyObject = new CComObject<CMyObject>;
       
       // Register your type-library
       ITypeLib *ptLib = 0;
       HRVERIFY(LoadTypeLib(L"AtlClientApp.tlb", &ptLib), "LoadTypeLib");
       
       // Initialize your IActiveScriptSite implementation with your
       // object's ITypeInfo...
       ptLib->GetTypeInfoOfGuid(CLSID_MyObject, &pMySite->m_pTypeInfo);
       ptLib->Release();
       
       // Initialize your IActiveScriptSite implementation with your
       // script object's IUnknown interface...
       HRVERIFY(pMyObject->QueryInterface(IID_IUnknown,
          (void **)&pMySite->m_pUnkScriptObject), "IUnknown initialization");
       
       // Start inproc script engine, VBSCRIPT.DLL
       IActiveScript *pAS;
       HRVERIFY(CoCreateInstance(CLSID_VBScript, NULL, CLSCTX_INPROC_SERVER,
          IID_IActiveScript, (void **)&pAS), 
          "CoCreateInstance() for CLSID_VBScript");
       
       // Get engine's IActiveScriptParse interface.
       IActiveScriptParse *pASP;
       HRVERIFY(pAS->QueryInterface(IID_IActiveScriptParse, (void **)&pASP),
          "QueryInterface() for IID_IActiveScriptParse");
       
       // Give engine your IActiveScriptSite interface...
       HRVERIFY(pAS->SetScriptSite((IActiveScriptSite *)pMySite),
          "IActiveScript::SetScriptSite()");
       
       // Give the engine a chance to initialize itself...
       HRVERIFY(pASP->InitNew(), "IActiveScriptParse::InitNew()");
       
       // Add a root-level item to the engine's name space...
       HRVERIFY(pAS->AddNamedItem(L"MyObject", SCRIPTITEM_ISVISIBLE |
          SCRIPTITEM_ISSOURCE), "IActiveScript::AddNamedItem()");
       
       // Get text from edit-box...
       HWND editHwnd = GetDlgItem(IDC_EDIT1);
       char szBuf[1024];
       int len = ::GetWindowText(editHwnd, szBuf, 1024);
       szBuf[len] = 0;
       
       // Convert it to a wide-char string...
       WCHAR wcBuf[1024];
       memset(wcBuf, 0, sizeof(WCHAR)*1024);
       MultiByteToWideChar(CP_ACP, 0, szBuf, strlen(szBuf), wcBuf, 1024);
       
       // Parse the code scriptlet...
       EXCEPINFO ei;
       BSTR pParseText = ::SysAllocString(wcBuf);
       HRVERIFY(pASP->ParseScriptText(pParseText, L"MyObject", NULL, NULL, 0,
          0, 0L, NULL, &ei), "ParseScriptText");
       ::SysFreeString(pParseText);
       
       // Set the engine state. This line actually triggers the execution
       // of the script.
       HRVERIFY(pAS->SetScriptState(SCRIPTSTATE_CONNECTED), "SetScriptState");
       
       // Let user know script-run is finished...
       ::MessageBox(NULL, "Script finished, click me to fire event...", "",
          MB_SETFOREGROUND);
       
       // Fire an event...
       pMyObject->Fire_MyEvent();
       
       // Close script and release interfaces...
       pAS->Close();
       pASP->Release();
       pAS->Release();
       
       // Delete site & objects...
       delete pMySite;
       delete pMyObject;
       return 0;
    					

  7. Add the following to the top of the same file (ClientDlg.h), just below the #include for atlhost.h:
       #include "AtlClientApp.h"
       #include "MyObject.h"
       #include "MyScriptSite.h"
       void HRVERIFY(HRESULT hr, char * msg);
       extern const GUID CLSID_VBScript;
    					

  8. Add the following to the end of your ClientDlg.cpp:
       void HRVERIFY(HRESULT hr, char * msg)
       {
          if(FAILED(hr)) {
             static char buf[1024];
             sprintf(buf, "Error: %08lx, %s", hr, msg);
             ::MessageBox(NULL, buf, "", MB_SETFOREGROUND);
             _exit(0);
          }
    
       }
    
       // Script Engine CLSIDs...
       #include <initguid.h>
       DEFINE_GUID(CLSID_VBScript, 0xb54f3741, 0x5b07, 0x11cf, 0xa4, 0xb0, 0x0,
                   0xaa, 0x0, 0x4a, 0x55, 0xe8);
    					

  9. Right-click on the IMyObject interface in ClassView, add the following two methods named SayHi and SayHi2, and implement them as follows:
       STDMETHODIMP CMyObject::SayHi()
       {
          ::MessageBox(NULL, "Inside SayHi()", "", MB_SETFOREGROUND);
          return S_OK;
       }
    
       STDMETHODIMP CMyObject::SayHi2()
       {
          ::MessageBox(NULL, "Inside SayHi2()", "", MB_SETFOREGROUND);
          return S_OK;
       }
    					

  10. Right-click on your IMyObjectEvents interface and add a method named MyEvent. Before going to the next step, you should Choose 'Rebuild All' from the Build menu, even though it won't completely build yet. This is so your project gets updated and ClassView will recognize your event in the next step.
  11. In ClassView, right-click on your CMyObject class, and select Implement Connection Point. Check the IMyObjectEvents interface, and click OK.
  12. Select Rebuild All from the Build menu and run the example. Type in the following example VBScript in the edit box, and click Run:
       SayHi
    
       Sub MyObject_MyEvent
          SayHi2
       End Sub
    					

REFERENCES

For more information Microsoft ActiveX Script Hosting, click the following article number to view the article in the Microsoft Knowledge Base:
221992 How to add support for hosing VBScript to your MFC application
183698 Axsh.exe demonstrates how to implement an active scripting host
168214 MFCAXS implements an Active Script Host using MFC

Properties

Article ID: 223139 - Last Review: September 1, 2005 - Revision: 3.0
APPLIES TO
  • Microsoft ActiveX Template Library 3.0
  • Microsoft Visual C++ 5.0 Enterprise Edition
  • Microsoft Visual C++ 6.0 Enterprise Edition
  • Microsoft Visual C++ 5.0 Professional Edition
  • Microsoft Visual C++ 6.0 Professional Edition
  • Microsoft Visual C++, 32-bit Learning Edition 6.0
Keywords: 
kbhowto kbactivexscript KB223139

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