new interfaces:<UL>	<LI><TT>OnInitialUpdate</TT>, called when the view is first created<BR>	<BR>		<LI><TT>OnUpdate</TT>, called when the document updates its views</UL><P>To create a new view to add to the CDVTest project, follow these steps:<DL>	<DD>1. Open ClassWizard.<BR>	<BR>	2. Press the button labeled Add Class and select the New option from the drop-down	menu.<BR>	<BR>	3. Use the values from Table 23.6 to fill in the Add Class dialog box.<BR>	<BR>	4. Click OK and close ClassWizard.</DL><H4><FONT COLOR="#000077">Table 23.6. Values used to add the CDisplayView class.</FONT></H4><P><TABLE BORDER="1">	<TR ALIGN="LEFT" rowspan="1">		<TD ALIGN="LEFT" VALIGN="TOP"><B>Control</B></TD>		<TD ALIGN="LEFT" VALIGN="TOP"><B>Value</B></TD>	</TR>	<TR ALIGN="LEFT" rowspan="1">		<TD ALIGN="LEFT" VALIGN="TOP">Name</TD>		<TD ALIGN="LEFT" VALIGN="TOP"><TT>CDisplayView</TT></TD>	</TR>	<TR ALIGN="LEFT" rowspan="1">		<TD ALIGN="LEFT" VALIGN="TOP">Base Class</TD>		<TD ALIGN="LEFT" VALIGN="TOP"><TT>CView</TT></TD>	</TR>	<TR ALIGN="LEFT" rowspan="1">		<TD ALIGN="LEFT" VALIGN="TOP">OLE Automation</TD>		<TD ALIGN="LEFT" VALIGN="TOP">None</TD>	</TR></TABLE></P><P>ClassWizard adds the new view to the project and creates some default initializationfunctions. However, the view class isn't useful until you do some additional workto associate it with the document class and define how it displays information.</P><P>When you create a new view using ClassWizard, you must add functions to handlethe Document/View interfaces; they aren't automatically created as they are for viewscreated by AppWizard when a new project is created. Using ClassWizard, add two message-handlingfunctions to the <TT>CDisplayView</TT> class using the values from Table 23.7.<H4><FONT COLOR="#000077">Table 23.7. New member functions for the CDisplayView class.</FONT></H4><P><TABLE BORDER="1">	<TR ALIGN="LEFT" rowspan="1">		<TD ALIGN="LEFT" VALIGN="TOP"><B>Class Name</B></TD>		<TD ALIGN="LEFT" VALIGN="TOP"><B>Object ID</B></TD>		<TD ALIGN="LEFT" VALIGN="TOP"><B>Message</B></TD>	</TR>	<TR ALIGN="LEFT" rowspan="1">		<TD ALIGN="LEFT" VALIGN="TOP"><TT>CDisplayView</TT></TD>		<TD ALIGN="LEFT" VALIGN="TOP"><TT>CDisplayView</TT></TD>		<TD ALIGN="LEFT" VALIGN="TOP"><TT>OnInitialUpdate</TT></TD>	</TR>	<TR ALIGN="LEFT" rowspan="1">		<TD ALIGN="LEFT" VALIGN="TOP"><TT>CDisplayView</TT></TD>		<TD ALIGN="LEFT" VALIGN="TOP"><TT>CDisplayView</TT></TD>		<TD ALIGN="LEFT" VALIGN="TOP"><TT>OnUpdate</TT></TD>	</TR></TABLE><H3><FONT COLOR="#000077"><B>Modifying the <TT>OnDraw</TT> Function</B></FONT></H3><P>As discussed earlier, when you complete it, the <TT>CDisplayView</TT> class willlist the names contained in the <TT>CDVTestDoc</TT> document class. Like other <TT>OnDraw</TT>functions, <TT>CDisplayView::OnDraw</TT> retrieves a pointer to the document classand collects information about the items to be displayed in the view. The sourcecode for <TT>CDisplayView::OnDraw</TT> is provided in Listing 23.5.<H4><FONT COLOR="#000077">TYPE: Listing 23.5. Source code for CDisplayView::OnDraw.</FONT></H4><PRE><FONT COLOR="#0066FF"><TT>void CDisplayView::OnDraw(CDC* pDC)</TT><TT>{</TT><TT>    CDVTestDoc* pDoc = (CDVTestDoc*)GetDocument();</TT><TT>    ASSERT_VALID(pDoc);</TT><TT>    // Calculate the space required for a single</TT><TT>    // line of text, including the inter-line area.</TT><TT>    TEXTMETRIC  tm;</TT><TT>    pDC-&gt;GetTextMetrics( &amp;tm );</TT><TT>    int nLineHeight = tm.tmHeight + tm.tmExternalLeading;</TT><TT>    CPoint  ptText( 0, 0 );</TT><TT>    for( int nIndex = 0; nIndex &lt; pDoc-&gt;GetCount(); nIndex++ )</TT><TT>    {</TT><TT>        CString szName = pDoc-&gt;GetName( nIndex );</TT><TT>        pDC-&gt;TextOut( ptText.x, ptText.y, szName );</TT><TT>        ptText.y += nLineHeight;</TT><TT>    }</TT></FONT></PRE><P><TT>}</TT> Notice that the <TT>OnDraw</TT> function used in <TT>CDisplayView</TT>is the same as the <TT>CDVTestView::OnDraw</TT> function in Listing 9.14. Althoughthat view had exclusive access to its document, the same source code works when thedocument is shared by multiple views. You add the code for the <TT>OnInitialUpdate</TT>and <TT>OnUpdate</TT> member functions later, in the section &quot;Adding the <TT>OnInitialUpdate</TT>and <TT>OnUpdate</TT> Member Functions.&quot;</P><P>Because the <TT>OnDraw</TT> function must access the <TT>CDVTestDoc</TT> class,add this <TT>#include</TT> directive for the <TT>CDVTestDoc</TT> class:</P><PRE><FONT COLOR="#0066FF"><TT>#include &quot;DVTestDoc.h&quot;</TT></FONT></PRE><P>Add this include statement after the other include statements near the beginningof the <TT>DisplayView.cpp</TT> source file.<H3><FONT COLOR="#000077"><B>Creating and Maintaining Multiple Document Templates</B></FONT></H3><P>When a single view and document are associated with each other, a <TT>CMultiDocTemplate</TT>is passed to the MFC framework, and the application never sees it again. When multipleviews are created, the application class must keep track of the document templatesused for the document and view associations. The application class stores these pointersand provides them to the <TT>CMainFrame</TT> class when needed. Add the source codein Listing 23.6 to the implementation section of the <TT>CDVTestApp</TT> class declaration.These additions declare two member variables that are used to cache pointers to thedocument templates and two member functions used to get access to the pointers.<H4><FONT COLOR="#000077">TYPE: Listing 23.6. Changes to the CDVTestApp class declaration.</FONT></H4><PRE><FONT COLOR="#0066FF"><TT>public:</TT><TT>    CDocTemplate* GetDisplayTemplate() const;</TT><TT>    CDocTemplate* GetFormTemplate() const;</TT><TT>private:</TT><TT>    CDocTemplate* m_pDisplayTemplate;</TT></FONT></PRE><P><TT>CDocTemplate* m_pFormTemplate;</TT> The two document template pointers areset during the <TT>CDVTestApp::InitInstance</TT> member function. Instead of creatinga <TT>CMultiDocTemplate</TT> object and passing it immediately to the <TT>AddDocTemplate</TT>function, <TT>CMultiDocTemplate</TT> objects are created, and their pointers arestored in the new member variables. Replace the current code used to create the documenttemplates in <TT>CDVTestApp::InitInstance</TT> with the source code provided in Listing23.7.<H4><FONT COLOR="#000077">TYPE: Listing 23.7. Changes to CDVTestApp::InitInstancecreating two document templates.</FONT></H4><PRE><FONT COLOR="#0066FF"><TT>m_pFormTemplate = new CMultiDocTemplate(</TT><TT>                                   IDR_DVTESTTYPE,</TT><TT>                                   RUNTIME_CLASS(CDVTestDoc),</TT><TT>                                   RUNTIME_CLASS(CChildFrame),</TT><TT>                                   RUNTIME_CLASS(CFormTest) );</TT><TT> m_pDisplayTemplate = new CMultiDocTemplate(</TT><TT>                                   IDR_DISPLAYTYPE,</TT><TT>                                   RUNTIME_CLASS(CDVTestDoc),</TT><TT>                                   RUNTIME_CLASS(CChildFrame),</TT><TT>                                   RUNTIME_CLASS(CDisplayView) );</TT></FONT></PRE><P><TT>AddDocTemplate( m_pFormTemplate );</TT> Each of the document templates createdin Listing 23.7 describes views associated with the <TT>CDVTestDoc</TT> class. Oneof the document templates uses the <TT>CFormTest</TT> class from earlier this hour,whereas the other template uses the <TT>CDisplayView</TT> class. Because this classis new to the <TT>DVTest.cpp</TT> file, add an <TT>#include</TT> directive for the<TT>CDisplayView</TT> class:</P><PRE><FONT COLOR="#0066FF"><TT>#include &quot;DisplayView.h&quot;</TT></FONT></PRE><P>Listing 23.8 contains the source for the new <TT>CDVTestApp</TT> functions thatreturn pointers to the <TT>CDocTemplate</TT> pointers created during <TT>CDVTest::OnInitInstance</TT>.The <TT>CMainFrame</TT> class uses these pointers when creating new views. Add thesource code in Listing 23.8 to the <TT>DVTest.cpp</TT> file.<H4><FONT COLOR="#000077">TYPE: Listing 23.8. CDVTestApp functions used to returnpointers to the document templates.</FONT></H4><PRE><FONT COLOR="#0066FF"><TT>CDocTemplate* CDVTestApp::GetDisplayTemplate() const</TT><TT>{</TT><TT>    return m_pDisplayTemplate;</TT><TT>}</TT><TT>CDocTemplate* CDVTestApp::GetFormTemplate() const</TT><TT>{</TT><TT>    return m_pFormTemplate;</TT><TT>}</TT></FONT></PRE><H3><FONT COLOR="#000077"><B>Adding Shared Resources</B></FONT></H3><P>One of the parameters used when creating a document template is the <I>shared-resourceidentifier</I>. This resource ID is used to identify several different resourcesused by the view:<UL>	<LI>A resource string; specifying the file type, file extension, and document name	for the document template<BR>	<BR>		<LI>An icon for the view<BR>	<BR>		<LI>A menu used when the view is active</UL><P>Each of these resources must be created for a new view. Although sharing an existingresource ID is possible, providing at least a customized icon for the new view isa much better practice. The name of the current shared resource ID is <TT>IDR_DVTESTTYPE</TT>;for the new view, you will create a shared resource ID named <TT>IDR_DISPLAYTYPE</TT>.<H4><FONT COLOR="#000077">Creating a Menu for the New View</FONT></H4><P>Click the <TT>IDR_DVTESTTYPE</TT> menu item, and use Copy and Paste to createa new menu item. Rename the new item as <TT>IDR_DISPLAYTYPE</TT>; you can open theproperty page by right-clicking the icon and selecting Properties from the pop-upmenu.<H4><FONT COLOR="#000077">Creating an Icon for the New View</FONT></H4><P>Create an <TT>IDR_DISPLAYTYPE</TT> icon by opening the Icon folder on the resourcetree. Create a copy of the existing <TT>IDR_DVTESTTYPE</TT> icon by using the Editmenu to copy and paste the icon, or by pressing Ctrl+C, then Ctrl+V.<H4><FONT COLOR="#000077">Using a Resource String</FONT></H4><P>The resource string for each document template is stored in a String Table resource.Go to the ResourceView window and click the String Table icon. In the DVTest project,the resource string for the current document template is stored under the name <TT>IDR_DVTESTTYPE</TT>.You can add a new string to the String Table by pressing the Insert key on the keyboard.Create a new string resource named <TT>IDR_DISPLAYTYPE</TT> with the following stringvalue:</P><PRE><FONT COLOR="#0066FF"><TT>\nDVTest\n\n\n\nDVTest.Document\nDVTest Document</TT></FONT></PRE><P>The contents of the resource string are split into seven sections, and each sectionis separated by <TT>\n</TT>. Each of the seven sections has a particular purpose,as shown in Table 23.8.<H4><FONT COLOR="#000077">Table 23.8. Values for subsections of resource stringsused in DVTest.</FONT></H4><P><TABLE BORDER="1">	<TR ALIGN="LEFT" rowspan="1">		<TD ALIGN="LEFT" VALIGN="TOP"><B>Section</B></TD>		<TD ALIGN="LEFT" VALIGN="TOP"><TT>IDR_DVTEST</TT></TD>		<TD ALIGN="LEFT" VALIGN="TOP"><TT>IDR_DISPLAYTYPE</TT></TD>	</TR>	<TR ALIGN="LEFT" rowspan="1">		<TD ALIGN="LEFT" VALIGN="TOP">Title</TD>		<TD ALIGN="LEFT" VALIGN="TOP"></TD>		<TD ALIGN="LEFT" VALIGN="TOP"></TD>	</TR>	<TR ALIGN="LEFT" rowspan="1">		<TD ALIGN="LEFT" VALIGN="TOP">Document Name</TD>		<TD ALIGN="LEFT" VALIGN="TOP">DVTest</TD>		<TD ALIGN="LEFT" VALIGN="TOP">DVTest</TD>	</TR>	<TR ALIGN="LEFT" rowspan="1">		<TD ALIGN="LEFT" VALIGN="TOP">New File Name</TD>		<TD ALIGN="LEFT" VALIGN="TOP">DVTest</TD>		<TD ALIGN="LEFT" VALIGN="TOP"></TD>	</TR>	<TR ALIGN="LEFT" rowspan="1">		<TD ALIGN="LEFT" VALIGN="TOP">Filter Name</TD>		<TD ALIGN="LEFT" VALIGN="TOP"></TD>		<TD ALIGN="LEFT" VALIGN="TOP"></TD>	</TR>	<TR ALIGN="LEFT" rowspan="1">		<TD ALIGN="LEFT" VALIGN="TOP">Filter Extension</TD>		<TD ALIGN="LEFT" VALIGN="TOP"></TD>		<TD ALIGN="LEFT" VALIGN="TOP"></TD>	</TR>	<TR ALIGN="LEFT" rowspan="1">		<TD ALIGN="LEFT" VALIGN="TOP">Type ID</TD>		<TD ALIGN="LEFT" VALIGN="TOP">DVTest.Document</TD>		<TD ALIGN="LEFT" VALIGN="TOP">DVTest.Document</TD>	</TR>	<TR ALIGN="LEFT" rowspan="1">		<TD ALIGN="LEFT" VALIGN="TOP">Type Name</TD>		<TD ALIGN="LEFT" VALIGN="TOP">DVTest Document</TD>		<TD ALIGN="LEFT" VALIGN="TOP">DVTest Document</TD>	</TR></TABLE></P><P>The new resource string is almost the same as the original string. The only differenceis that there is no entry for the section marked New File Name. This is a clue tothe MFC framework that this document template is not used to create new documents;instead, it is used only to open a new view on an existing document. You don't haveto worry too much about the purpose of each segment. The MFC framework uses thesesegments when registering your application with Windows, and when opening new viewsand documents.<H3><FONT COLOR="#000077"><B>Adding Menu Items for New Views</B></FONT></H3><P>You add new views by selecting a menu item from the Window menu. Add the menuitems using the Developer Studio resource editor, as you learned in Hour 10, &quot;Menus.&quot;Use the values from Table 23.9 to add the menu items to the <TT>IDR_DISPLAYTYPE</TT>and <TT>IDR_DVTESTTYPE</TT> menus, and to add message-handling functions to the <TT>CMainFrame</TT>class.<H4><FONT COLOR="#000077">Table 23.9. New member functions for the CMainFrame class.</FONT></H4><P><TABLE BORDER="1">	<TR ALIGN="LEFT" rowspan="1">		<TD ALIGN="LEFT" VALIGN="TOP"><B>Menu ID</B></TD>		<TD ALIGN="LEFT" VALIGN="TOP"><B>Caption</B></TD>		<TD ALIGN="LEFT" VALIGN="TOP"><B>Event</B></TD>		<TD ALIGN="LEFT" VALIGN="TOP"><B>Function Name</B></TD>	</TR>	<TR ALIGN="LEFT" rowspan="1">		<TD ALIGN="LEFT" VALIGN="TOP"><TT>ID_WINDOW_DISPLAY</TT></TD>		<TD ALIGN="LEFT" VALIGN="TOP">&amp;Display View</TD>		<TD ALIGN="LEFT" VALIGN="TOP"><TT>COMMAND</TT></TD>		<TD ALIGN="LEFT" VALIGN="TOP"><TT>OnWindowDisplay</TT></TD>