ch06.htm

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  specify the caption as E&xit. 
  <P></P>
  <DT>
  <DD><B>5. </B>Add a function to the button using the Class Wizard. Change the 
  code in this function to call OnOK. Remember, the OnOK function causes the 
  application to close. 
  <P></P></DD></DL>
<BLOCKQUOTE>
  <P>
  <HR>
  <STRONG>NOTE:</STRONG> If you don't remember how to add the OnOK function, 
  review the section "Closing the Application" on Day 2, "Using Controls in Your 
  Application," for an example. 
  <HR>
</BLOCKQUOTE>
<H3><A name=Heading8></A>Adding and Customizing a Menu</H3>
<P>Now that you have the basic application built, it's time to start creating a 
menu for the application. To create a menu, you will first add a menu resource 
to your project. When you add the resource, Visual C++ automatically invokes the 
Menu Designer, which allows you to customize the menu. The following steps show 
you how to add and customize a menu:</P>
<P>
<DL>
  <DT>
  <DD><B>1. </B>Select the Resource View tab in the workspace pane. 
  <P></P>
  <DT>
  <DD><B>2. </B>Select the project resources folder at the top of the tree; in 
  your example, this is Menus. 
  <P></P>
  <DT>
  <DD><B>3. </B>Right-click the mouse to bring up a pop-up menu. 
  <P></P>
  <DT>
  <DD><B>4. </B>Select Insert from the pop-up menu. 
  <P></P>
  <DT>
  <DD><B>5. </B>In the Insert Resource dialog that opens, select Menu from the 
  list of available resources, as in Figure 6.1. Click the New button. 
  <P></P></DD></DL>
<P><A href="javascript:popUp('06fig01.gif')"><B>FIGURE 6.1.</B></A><B> 
</B><I>The Insert Resource dialog.</I></P>
<P><I></I>
<DL>
  <DT><I></I>
  <DD><B>6. </B>The Menu Designer opens in the editing area of Developer Studio. 
  The first menu spot is highlighted, as shown in Figure 6.2. 
  <P></P></DD></DL>
<P><A href="javascript:popUp('06fig02a.gif')"><B>FIGURE 6.2.</B></A><B> 
</B><I>An empty menu.</I></P>
<P>At this point, you have created the menu resource and you are ready to 
customize it by adding menu items. To add a menu item, follow these steps:</P>
<P>
<DL>
  <DT>
  <DD><B>1. </B>Right-click the mouse on the highlighted area and select 
  Properties from the pop-up menu. 
  <P></P>
  <DT>
  <DD><B>2. </B>Enter the menu item's Caption. For this example, enter 
  <B>&amp;File</B> and close the Properties dialog. 
  <P></P></DD></DL>
<BLOCKQUOTE>
  <P>
  <HR>
  <STRONG>NOTE:</STRONG> You are in the menu Properties dialog to specify the 
  text that the user will see on the menu bar while the application is running. 
  Because the Pop-up check box is checked (by default on any menu items on the 
  top-level menu bar), this menu element doesn't trigger any application 
  functionality and thus doesn't need to have an object ID assigned to it. 
  <HR>
</BLOCKQUOTE>
<DL>
  <DT><B></B>
  <DD><B>3. </B>The first drop-down menu location is highlighted. To add this 
  menu item, right-click the mouse again on the highlighted area and select 
  Properties from the pop-up menu. 
  <P></P>
  <DT>
  <DD><B>4. </B>Enter an ID and caption for the menu item. For this example, 
  enter <B>IDM_FILE_HELLO</B> for the ID and <B>&amp;Hello</B> for the Caption. 
  Close the dialog. 
  <P></P></DD></DL>
<BLOCKQUOTE>
  <P>
  <HR>
  <STRONG>NOTE:</STRONG> This time in the menu Properties dialog, you not only 
  specify the text that the user will see when the menu is opened from the menu 
  bar, but you also specify the object ID that will be used in the event message 
  handler to determine what function receives each of the menu events. 
  <HR>
</BLOCKQUOTE>
<P>At this point you have created a menu with a single menu item. You can 
continue to add menu items by repeating steps 3 and 4 of the preceding list for 
each of the highlighted areas. You can also add separators onto the menu. A 
<I>separator</I> is a dividing line that runs across the menu to separate two 
functional areas of menu selections. To add a separator, perform the following 
steps:</P>
<P><A href="javascript:popUp('06fig02.gif')"><B>FIGURE 6.3.</B></A><B> 
</B><I>Specifying a menu separator.</I></P>
<P><I></I>
<DL>
  <DT><I></I>
  <DD><B>1. </B>Select the highlighted area where you want the separator to be 
  placed. In the example you created, the second drop-down menu location should 
  be highlighted. Open the properties dialog as you did in step 3 in the 
  preceding list. To add a separator, simply select the Separator option, as 
  shown in Figure 6.3, and close the dialog. 
  <P></P></DD></DL>
<P>To complete your sample program, follow the same steps I just described to 
add an Exit item to your File menu and a second menu called Help with one menu 
item called About. The following steps, which resemble the preceding list of 
steps, walk you through adding these additional items:</P>
<P>
<DL>
  <DT>
  <DD><B>1. </B>Open the properties dialog for the third drop-down location and 
  specify the ID as IDM_FILE_EXIT and the caption as E&amp;xit. Close the 
  dialog. 
  <P></P>
  <DT>
  <DD><B>2. </B>Select the second top-level menu location and open the 
  properties dialog. Specify the caption as &amp;Help and close the dialog. 
  <P></P>
  <DT>
  <DD><B>3. </B>Open the properties dialog for the first drop-down location on 
  the second top-level menu. Specify the ID as ID_HELP_ABOUT and the caption as 
  &amp;About. Close the dialog. 
  <P></P></DD></DL>
<P>At this point, your menu is created; however, it is not attached to your 
application.</P>
<P>
<H3><A name=Heading9></A>Attaching the Menu to Your Dialog Window</H3>
<P>You now have a menu that you can use in your application. If you compile and 
run your application at this point, however, the menu doesn't appear. You still 
need to attach the menu to your dialog window. You can attach a menu by 
following these steps:</P>
<P>
<DL>
  <DT>
  <DD><B>1. </B>Open the dialog painter by double-clicking the primary 
  application dialog in the Dialog folder in the Workspace pane. For this 
  example, double-click on IDD_MENUS_DIALOG. 
  <P></P>
  <DT>
  <DD><B>2. </B>Select the entire dialog window, making sure that no controls 
  are selected, and open the dialog's properties dialog. (What you are doing is 
  opening the properties for the dialog window itself, not for any of the 
  controls that might be on the window.) 
  <P></P>
  <DT>
  <DD><B>3. </B>Select the menu you have designed from the Menu drop-down list 
  box, as shown in Figure 6.4. 
  <P></P></DD></DL>
<P><A href="javascript:popUp('06fig03.gif')"><B>FIGURE 6.4.</B></A><B> 
</B><I>Attaching the menu to the dialog window.</I></P>
<P>If you compile and run your application, you find that the menu is attached 
to the application dialog, as shown in Figure 6.5. You can select menu entries 
as you do with any other Windows application--with one small difference. At this 
point, when you select one of the menu entries, nothing happens. You still need 
to attach functionality to your menu.</P>
<P><A href="javascript:popUp('06fig04.gif')"><B>FIGURE 6.5.</B></A><B> 
</B><I>The menu is now part of the application dialog.</I></P>
<P><I></I>
<H3><A name=Heading10></A>Attaching Functionality to Menu Entries</H3>
<P>Now that you have a menu as part of your application, it sure would be nice 
if it actually did something. Well, before your menu can do anything, you have 
to tell it what to do, just like everything else in your Visual C++ 
applications. To attach some functionality to your menu, follow these steps:</P>
<P><A href="javascript:popUp('06fig05.gif')"><B>FIGURE 6.6.</B></A><B> 
</B><I>The menu is now part of the application.</I></P>
<P><I></I>
<DL>
  <DT><I></I>
  <DD><B>1. </B>Open the Menu Designer to your menu. 
  <P></P>
  <DT>
  <DD><B>2. </B>Open the Class Wizard from the View menu. 
  <P></P>
  <DT>
  <DD><B>3. </B>The Adding a Class dialog is displayed for you, just as it was 
  yesterday when you added a second dialog. Leave the dialog selection on Select 
  an Existing Class and click OK (see Figure 6.6). 
  <P></P>
  <DT>
  <DD>Yesterday, when you were adding a second dialog window to your 
  application, you needed to create a new C++ class for that window. For today's 
  menu, you want to attach it to the existing C++ class for the dialog window to 
  which the menu is attached. 
  <P></P>
  <DT>
  <DD><B>4. </B>Choose the C++ class of the primary dialog window from the list 
  of available classes in the Select Class dialog. For this example, select 
  CMenusDlg, as shown in Figure 6.7. This tells Visual C++ that all the 
  functionality that you will call from the various menu entries is part of the 
  same dialog class of the window that it's attached to. 
  <P></P></DD></DL>
<P><A href="javascript:popUp('06fig06.gif')"><B>FIGURE 6.7.</B></A><B> 
</B><I>The Select Class dialog.</I></P>
<P>For the menu elements that you want to use to trigger new functions in your 
application, you can add event-handler functions through the Class Wizard, just 
as you can with controls that you place on the dialog window.</P>
<P>For this example, add a function for the IDM_FILE_HELLO object (the Hello 
menu) on the COMMAND event message. Name the function OnHello and add the code 
in Listing 6.1 to the function.</P>
<P>
<H4>LISTING 6.1. THE ONHELLO FUNCTION.</H4><PRE> 1: void CMenusDlg::OnHello() 
 2: {
 3:     // TODO: Add your command handler code here
 4: 
 5:     ///////////////////////
 6:     // MY CODE STARTS HERE
 7:     ///////////////////////
 8: 
 9:     // Display a message for the user
10:     MessageBox("Hello there", "Hello");
11: 
12:     ///////////////////////
13:     // MY CODE ENDS HERE
14:     ///////////////////////
</PRE><PRE>15: }</PRE>
<BLOCKQUOTE>
  <P>
  <HR>
  <STRONG>NOTE:</STRONG> The COMMAND event message is the message that is passed 
  to the application window when a menu entry is selected. Placing a function on 
  this event message has the same effect as placing a function on the menu entry 
  selection. 
  <HR>
</BLOCKQUOTE>
<P>You can call existing event handlers from menu elements by adding the 
existing function to the menu COMMAND event. You can do this by adding a 
function to the menu object ID and then specifying the existing function name 
instead of accepting the suggested function name.</P>
<P>To reuse the OnExit function for the Exit menu element, reopen the Menu 
Designer and then reopen the Class Wizard. When the Class Wizard is displayed, 
add a function for the IDM_FILE_EXIT object on the COMMAND event message. Do not 
accept the default function name presented to you by the Class Wizard. Enter the 
function name <B>OnExit</B>. This automatically attaches the existing OnExit 
function that you created with your Exit button earlier.</P>
<P>To round out your example's functionality, add a function to the 
ID_HELP_ABOUT object on the COMMAND event message. Edit the function as in 
Listing 6.2.</P>
<P>
<H4>LISTING 6.2. THE ONHELPABOUT FUNCTION.</H4><PRE> 1: void CMenusDlg::OnHelpAbout() 
 2: {
 3:     // TODO: Add your command handler code here
 4: 
 5:     ///////////////////////
 6:     // MY CODE STARTS HERE
 7:     ///////////////////////
 8: 
 9:     // Declare an instance of the About window
10:     CAboutDlg dlgAbout;
11: 
12:     // Show the About window
13:     dlgAbout.DoModal();