Adding A Block Using ActiveX Client In C++

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问题：
How do I add a block to a drawing through an ActiveX Client in C++?

解答：
There are two interface objects that are mirrored to their ObjectARX
counterparts: IAcadBlocks to AcDbBlockTable and IAcadBlock to
AcDbBlockTableRecord. You then need to get to the interface objects and call the
appropriate methods.

These are the key steps to doing this:

1. Create a standalone MFC AppWiard EXE that is dialog-based.
2. Use the ClassWizard to import the following interfaces (from acad.tlb) and
declare them as private member variables of the dialog class:


IAcadApplication m_IApp;
    IAcadDocument     m_IDoc;

    IAcadBlock    m_IBlock;
    IAcadBlocks    m_IBlocks;

3. In the dialog's OnInitDialog(), assign a separate button handler, and get
the application and document object (a button with handler code shown below).

1. void CClientDlg::OnStart()
   
2. {
   
3.     HRESULT hr = NOERROR;
   
4.     CLSID clsid;
   
5.     LPUNKNOWN pUnk = NULL;
   
6.     LPDISPATCH pDisp = NULL;
   
7. 
   
8.     BeginWaitCursor();
   
9.     CoInitialize(NULL);
   
10.     hr = ::CLSIDFromProgID(L"AutoCAD.Application", &clsid);
    
11. 
    
12.     if (SUCCEEDED(hr))
    
13.     {
    
14.         if(::GetActiveObject(clsid, NULL, &pUnk) == S_OK)
    
15.         {
    
16.             VERIFY(pUnk->QueryInterface(IID_IDispatch,(LPVOID*)&pDisp) == S_OK);
    
17.             m_IApp.AttachDispatch(pDisp);
    
18.             pUnk->Release();
    
19.         }
    
20.         else
    
21.             VERIFY(m_IApp.CreateDispatch(clsid) == TRUE);
    
22. 
    
23.         m_IApp.SetVisible(TRUE);
    
24. 
    
25.         pDisp = m_IApp.GetActiveDocument();
    
26.         m_IDoc.AttachDispatch(pDisp);
    
27.     }
    
28.     else
    
29.         AfxMessageBox("Acad.Application is not registered!");
    
30.             //CoUninitialize(); // do this in the dialog's exit code
    
31.     EndWaitCursor();
    
32. }
    
33. 
    
34. 4. Create a button and its handler, then add the following code:
    
35. 
    
36. 
    
37. void CClientDlg::OnAddBlock()
    
38. {
    
39.     VARIANT var;
    
40.     double pt[3] = {2, 2, 0};
    
41.     getVariantFromDblArray(&var, pt);
    
42.     const char blkName[] = "TEST";
    
43.     LPDISPATCH p = m_IDoc.GetBlocks();
    
44.     m_IBlocks.AttachDispatch(p);
    
45.     p = m_IBlocks.Add(var, blkName);
    
46.     m_IBlock.AttachDispatch(p);
    
47. }
    
48. 
    
49. HRESULT getVariantFromDblArray(VARIANT* pVal, const double pt[3])
    
50. {
    
51.     pVal->vt = VT_ARRAY | VT_R8;
    
52. 
    
53.     SAFEARRAYBOUND rgsaBound;
    
54.     rgsaBound.lLbound = 0L;
    
55.     rgsaBound.cElements = 3;
    
56. 
    
57.     pVal->parray = SafeArrayCreate(VT_R8, 1, &rgsaBound);
    
58.     if (! pVal->parray)
    
59.         return E_OUTOFMEMORY;
    
60. 
    
61.     HRESULT hr;
    
62.     for (long i = 0; i < 3; i++)
    
63.         if ((hr = SafeArrayPutElement(pVal->parray, &i,
    
64. (void*)&pt))!=S_OK)
    
65.             return hr;
    
66.     return S_OK;
    
67. }
    

void CClientDlg::OnStart()<br /> {<br />     HRESULT hr = NOERROR;<br />     CLSID clsid;<br />     LPUNKNOWN pUnk = NULL;<br />     LPDISPATCH pDisp = NULL;<br /> <br />     BeginWaitCursor();<br />     CoInitialize(NULL);<br />     hr = ::CLSIDFromProgID(L"AutoCAD.Application", &clsid);<br /> <br />     if (SUCCEEDED(hr))<br />     {<br />         if(::GetActiveObject(clsid, NULL, &pUnk) == S_OK)<br />         {<br />             VERIFY(pUnk->QueryInterface(IID_IDispatch,(LPVOID*)&pDisp) == S_OK);<br />             m_IApp.AttachDispatch(pDisp);<br />             pUnk->Release();<br />         }<br />         else<br />             VERIFY(m_IApp.CreateDispatch(clsid) == TRUE);<br /> <br />         m_IApp.SetVisible(TRUE);<br /> <br />         pDisp = m_IApp.GetActiveDocument();<br />         m_IDoc.AttachDispatch(pDisp);<br />     }<br />     else<br />         AfxMessageBox("Acad.Application is not registered!");<br />             //CoUninitialize(); // do this in the dialog's exit code<br />     EndWaitCursor();<br /> }<br /> <br /> 4. Create a button and its handler, then add the following code:<br /> <br /> <br /> void CClientDlg::OnAddBlock()<br /> {<br />     VARIANT var;<br />     double pt[3] = {2, 2, 0};<br />     getVariantFromDblArray(&var, pt);<br />     const char blkName[] = "TEST";<br />     LPDISPATCH p = m_IDoc.GetBlocks();<br />     m_IBlocks.AttachDispatch(p);<br />     p = m_IBlocks.Add(var, blkName);<br />     m_IBlock.AttachDispatch(p);<br /> }<br /> <br /> HRESULT getVariantFromDblArray(VARIANT* pVal, const double pt[3])<br /> {<br />     pVal->vt = VT_ARRAY | VT_R8;<br /> <br />     SAFEARRAYBOUND rgsaBound;<br />     rgsaBound.lLbound = 0L;<br />     rgsaBound.cElements = 3;<br /> <br />     pVal->parray = SafeArrayCreate(VT_R8, 1, &rgsaBound);<br />     if (! pVal->parray)<br />         return E_OUTOFMEMORY;<br /> <br />     HRESULT hr;<br />     for (long i = 0; i < 3; i++)<br />         if ((hr = SafeArrayPutElement(pVal->parray, &i,<br /> (void*)&pt<i>))!=S_OK)<br />             return hr;<br />     return S_OK;<br /> }<br />