bar when the menu item is highlighted.</UL><H3><FONT COLOR="#000077"><B>Adding a Message-Handling Function</B></FONT></H3><P>After adding a menu item to the application's menu, the next step is to add amessage-handling function to handle the new menu item. As discussed in Hour 8, ClassWizardis used to create message-handling functions for MFC-based Windows programs. To adda message-handling function for the <TT>ID_FILE_HELLO</TT> menu item, follow thesesteps:<DL>	<DD>1. Open ClassWizard by pressing Ctrl+W or by right-clicking in a source code	window and selecting ClassWizard from the menu.<BR>	<BR>	2. Select the Message Maps tab and select the class that will handle the message	from the Class Name combo box--in this case, <TT>CMainFrame</TT>.<BR>	<BR>	3. Select the object that is generating the message from the Object ID list box--in	this case, <TT>ID_FILE_HELLO</TT>. Two message-handling functions are displayed in	the Messages list box.<BR>	<BR>	4. Select the <TT>COMMAND</TT> message from the Messages list box and click the Add	Function button. Accept the default name suggested by ClassWizard for the function	name--<TT>OnFileHello</TT>.<BR>	<BR>	5. Click OK to close ClassWizard.</DL><P>Edit the <TT>CMainFrame::OnFileHello</TT> function so that it looks like the functionprovided in Listing 10.1.<H4><FONT COLOR="#000077">TYPE: Listing 10.1. The CMainFrame::OnFileHello message-handlingfunction.</FONT></H4><PRE><FONT COLOR="#0066FF"><TT>void CMainFrame::OnFileHello()</TT><TT>{</TT><TT>    AfxMessageBox( &quot;Hello from the File menu&quot; );</TT><TT>}</TT></FONT></PRE><BLOCKQUOTE>	<P><HR><B> </B><FONT COLOR="#000077"><B>Just a Minute:</B></FONT><B> </B>These basic steps	are used to add all the menu items used in examples for the remaining hours in this	book. The Developer Studio tools are so easy to use that adding a new menu item will	be second nature in no time. <HR></BLOCKQUOTE><H2><FONT COLOR="#000077"><B>Creating a Shortcut Menu</B></FONT></H2><P><FONT COLOR="#000077"><B>New Term:</B></FONT><B> </B>A <I>shortcut menu</I>, sometimescalled a pop-up or context menu, is displayed by right-clicking on a window. Shortcutmenus provide a list of commonly used actions.</P><P>Creating a shortcut menu is similar to modifying an existing menu except thata new menu resource must be created as the first step. Most shortcut menus are displayedin response to the <TT>WM_CONTEXTMENU</TT> message, which is sent when the rightmouse button is pressed.<H3><FONT COLOR="#000077"><B>Creating the Resource</B></FONT></H3><P>Use the Developer Studio resource editor to create the context menu. To createthe new menu resource, use one of the following techniques:<UL>	<LI>Select Resource from the Insert menu and then select Menu from the Insert Resource	dialog box.<BR>	<BR>		<LI>Right-click the Menu folder in the ResourceView and then select Insert Menu from	the pop-up menu.</UL><P>Both of these methods opens a new menu resource for editing. Add a dummy captionfor the first top-level item on the menu bar. This caption is not displayed by themenu; it is used only as a placeholder.</P><P>Open the Properties dialog box for the menu resource by double-clicking the edgeof the menu resource, and change the resource ID to <TT>ID_POPUP</TT>. Using thevalues from Table 10.1, add three menu items under the dummy label.<H4><FONT COLOR="#000077">Table 10.1. Menu items added to the ID_POPUP menu resource.</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>	</TR>	<TR ALIGN="LEFT" rowspan="1">		<TD ALIGN="LEFT" VALIGN="TOP"><TT>ID_LIONS</TT></TD>		<TD ALIGN="LEFT" VALIGN="TOP">&amp;Lions</TD>	</TR>	<TR ALIGN="LEFT" rowspan="1">		<TD ALIGN="LEFT" VALIGN="TOP"><TT>ID_TIGERS</TT></TD>		<TD ALIGN="LEFT" VALIGN="TOP">&amp;Tigers</TD>	</TR>	<TR ALIGN="LEFT" rowspan="1">		<TD ALIGN="LEFT" VALIGN="TOP"><TT>ID_BEARS</TT></TD>		<TD ALIGN="LEFT" VALIGN="TOP">&amp;Bears</TD>	</TR></TABLE><H3><FONT COLOR="#000077"><B>Adding Message-Handling Functions</B></FONT></H3><P>The new context menu is displayed when a right mouse click is detected on theapplication's view. After a menu item has been selected, a message is displayed atthe menu's location, similar to the message displayed in the MouseTst example fromHour 8.</P><P>You must add two new variables to the <TT>CMenuView</TT> class: a <TT>CString</TT>variable that stores the message and a <TT>CPoint</TT> variable that stores the locationof the pop-up menu. Add the source code provided in Listing 10.2 to the <TT>CMenuView</TT>class after the <TT>//Implementation</TT> comment.<H4><FONT COLOR="#000077">TYPE: Listing 10.2. New member variables for the CMenuViewclass.</FONT></H4><PRE><FONT COLOR="#0066FF"><TT>// Implementation</TT><TT>protected:</TT><TT>    CPoint  m_ptMsg;</TT></FONT></PRE><P><TT>CString m_szMsg;</TT> The constructor for <TT>CMenuView</TT> must initializethe <TT>m_ptMsg</TT> variable. Edit the constructor for <TT>CMenuView</TT>, foundin <TT>MenuView.cpp</TT>, so it looks like the source code in Listing 10.3.<H4><FONT COLOR="#000077">TYPE: Listing 10.3. The constructor for CMenuView.</FONT></H4><PRE><FONT COLOR="#0066FF"><TT>CMenuView::CMenuView()</TT><TT>{</TT><TT>    m_ptMsg = CPoint(0,0);</TT></FONT></PRE><P><TT>}</TT> The <TT>CMenuView::OnDraw</TT> member function resembles the <TT>OnDraw</TT>member function from <TT>CMouseTestView</TT> in Hour 8. Both functions use the <TT>TextOut</TT>function to display a message at a certain point in the view. Edit the <TT>CMenuView::OnDraw</TT>function so that it looks like the function provided in Listing 10.4. You must removea few lines of AppWizard-supplied code.<H4><FONT COLOR="#000077">TYPE: Listing 10.4. The CMenuView::OnDraw member function.</FONT></H4><PRE><FONT COLOR="#0066FF"><TT>void CMenuView::OnDraw(CDC* pDC)</TT><TT>{</TT><TT>    pDC-&gt;TextOut( m_ptMsg.x, m_ptMsg.y, m_szMsg );</TT></FONT></PRE><P><TT>}</TT><H3><FONT COLOR="#000077"><B>Trapping Messages</B></FONT></H3><P>Use ClassWizard to add four new message-handling functions to the <TT>CMenuView</TT>class: three message-handling functions for the new menu items and one message-handlingfunction to detect the right-click from the mouse button. The steps used to add themessage-handling functions are similar to the ones used earlier when modifying anexisting menu, except these messages are handled by the <TT>CMenuView</TT> class.<DL>	<DD>1. Open ClassWizard by pressing Ctrl+W or right-clicking in a source code window	and selecting ClassWizard from the menu.<BR>	<BR>	2. Select the Message Maps tab and select the class that will handle the message	from the Class Name combo box--in this case, <TT>CMenuView</TT>.<BR>	<BR>	3. Select the object that is generating the message from the Object ID list box--in	this case, use one of the values from Table 10.2.<BR>	<BR>	4. Select a message from the Messages list box and click the Add Function button.	Accept the default name suggested by ClassWizard for the function name.<BR>	<BR>	5. Repeat this process for all entries in Table 10.2.<BR>	<BR>	6. Click OK to close ClassWizard.</DL><H4><FONT COLOR="#000077">Table 10.2. Values used to create message-handling functions.</FONT></H4><P><TABLE BORDER="1">	<TR ALIGN="LEFT" rowspan="1">		<TD ALIGN="LEFT" VALIGN="TOP"><B>Object ID</B></TD>		<TD ALIGN="LEFT" VALIGN="TOP"><B>Message</B></TD>		<TD ALIGN="LEFT" VALIGN="TOP"><B>Function</B></TD>	</TR>	<TR ALIGN="LEFT" rowspan="1">		<TD ALIGN="LEFT" VALIGN="TOP"><TT>CMenuView</TT></TD>		<TD ALIGN="LEFT" VALIGN="TOP"><TT>WM_CONTEXTMENU</TT></TD>		<TD ALIGN="LEFT" VALIGN="TOP"><TT>OnContextMenu</TT></TD>	</TR>	<TR ALIGN="LEFT" rowspan="1">		<TD ALIGN="LEFT" VALIGN="TOP"><TT>ID_LIONS</TT></TD>		<TD ALIGN="LEFT" VALIGN="TOP"><TT>COMMAND</TT></TD>		<TD ALIGN="LEFT" VALIGN="TOP"><TT>OnLions</TT></TD>	</TR>	<TR ALIGN="LEFT" rowspan="1">		<TD ALIGN="LEFT" VALIGN="TOP"><TT>ID_TIGERS</TT></TD>		<TD ALIGN="LEFT" VALIGN="TOP"><TT>COMMAND</TT></TD>		<TD ALIGN="LEFT" VALIGN="TOP"><TT>OnTigers</TT></TD>	</TR>	<TR ALIGN="LEFT" rowspan="1">		<TD ALIGN="LEFT" VALIGN="TOP"><TT>ID_BEARS</TT></TD>		<TD ALIGN="LEFT" VALIGN="TOP"><TT>COMMAND</TT></TD>		<TD ALIGN="LEFT" VALIGN="TOP"><TT>OnBears</TT></TD>	</TR></TABLE></P><P>The source code for the <TT>CMenuView::OnContextMenu</TT> message-handling functionis provided in Listing 10.5.<H4><FONT COLOR="#000077">TYPE: Listing 10.5. Popping up a menu when a right mousebutton is clicked.</FONT></H4><PRE><FONT COLOR="#0066FF"><TT>void CMenuView::OnContextMenu(UINT nFlags, CPoint point)</TT><TT>{</TT><TT>    CMenu   zooMenu;</TT><TT>    // Store popup point, and convert to client coordinates</TT><TT>    // for the drawing functions.</TT><TT>    m_ptMsg = point;</TT><TT>    ScreenToClient( &amp;m_ptMsg );</TT><TT>    zooMenu.LoadMenu( ID_POPUP );</TT><TT>    CMenu* pPopup = zooMenu.GetSubMenu( 0 );</TT><TT>    pPopup-&gt;TrackPopupMenu( TPM_LEFTALIGN|TPM_RIGHTBUTTON,</TT><TT>                            point.x,</TT><TT>                            point.y,</TT><TT>                            this );</TT></FONT></PRE><P><TT>}</TT> When a right mouse click is detected, the <TT>WM_CONTEXTMENU</TT> messageis sent to the application and the MFC framework calls the <TT>OnContextMenu</TT>message handler. The <TT>OnContextMenu</TT> function creates a <TT>CMenu</TT> objectand loads the <TT>ID_POPUP</TT> menu resource. The floating menu is displayed bycalling <TT>GetSubMenu</TT> and <TT>TrackPopupMenu</TT>.</P><P>The <TT>GetSubMenu</TT> function is used to skip past the dummy menu item at thetop of the <TT>ID_POPUP</TT> menu resource. The <TT>GetSubMenu</TT> function returnsa temporary pointer to the pop-up menu. Calling <TT>TrackPopupMenu</TT> causes thepop-up menu to be displayed and the menu item selection to automatically follow themouse cursor.</P><P>The source code for handling menu selection messages sent to the <TT>CMenuView</TT>class is provided in Listing 10.6.<H4><FONT COLOR="#000077">TYPE: Listing 10.6. Message-handling functions for floatingmenu items.</FONT></H4><PRE><FONT COLOR="#0066FF"><TT>void CMenuView::OnLions()</TT><TT>{</TT><TT>    m_szMsg = &quot;Lions are out&quot;;</TT><TT>    InvalidateRect( NULL );</TT><TT>}</TT><TT>void CMenuView::OnTigers()</TT><TT>{</TT><TT>    m_szMsg = &quot;Tigers are afoot&quot;;</TT><TT>    InvalidateRect( NULL );</TT><TT>}</TT>