The EX08A Example -- An ActiveX Control Dialog Container

Now it's time to build an application that uses a Calendar control in a dialog. Here are the steps to create the EX08A example:

1. Verify that the Calendar control is registered. If the control does not appear in the Visual C++ Gallery's Registered ActiveX Controls page, copy the files MSCal.ocx, MSCal.hlp, and MSCal.cnt to your system directory and register the control by running the REGCOMP program.

2. Run AppWizard to produce \vcpp32\ex08a\ex08a. Accept all of the default settings but two: select Single Document and deselect Printing And Print Preview. In the AppWizard Step 3 dialog, make sure the ActiveX Controls option is selected, as shown below.

   

3. Install the Calendar control in the EX08A project. Choose Add To Project from Visual C++'s Project menu, and then choose Components And Controls. Choose Registered ActiveX Controls, and then choose Calendar Control 8.0. ClassWizard generates two classes in the EX08A directory, as shown here.

   

4. Edit the Calendar control class to handle help messages. Add Calendar.cpp to the following message map code:

   BEGIN_MESSAGE_MAP(CCalendar, CWnd)     ON_WM_HELPINFO() END_MESSAGE_MAP()

   In the same file, add the OnHelpInfo function:

   BOOL CCalendar::OnHelpInfo(HELPINFO* pHelpInfo)  {         // Edit the following string for your system     ::WinHelp(GetSafeHwnd(), "c:\\winnt\\system32\\mscal.hlp",               HELP_FINDER, 0);     return FALSE; }

   In Calendar.h, add the function prototype and declare the message map:

   protected:     afx_msg BOOL OnHelpInfo(HELPINFO* pHelpInfo);     DECLARE_MESSAGE_MAP()

   The OnHelpInfo function is called if the user presses the F1 key when the Calendar control has the input focus. We have to add the message map code by hand because ClassWizard doesn't modify generated ActiveX classes.

   

   The ON_WM_HELPINFO macro maps the WM_HELP message, which is new to Microsoft Windows 95 and Microsoft Windows NT 4.0. You can use ON_WM_HELPINFO in any view or dialog class and then code the handler to activate any help system. Chapter 21 describes the MFC context-sensitive help system, some of which predates the WM_HELP message.

Use the dialog editor to create a new dialog resource. Choose Resource from Visual C++'s Insert menu, and then choose Dialog. The dialog editor assigns the ID IDD_DIALOG1 to the new dialog. Next change the ID to IDD_ACTIVEXDIALOG, change the dialog caption to ActiveX Dialog, and set the dialog's Context Help property (on the More Styles page). Accept the default OK and Cancel buttons with the IDs IDOK and IDCANCEL, and then add the other controls as shown in Figure 8-1. Make the Select Date button the default button. Drag the Calendar control from the control palette. Then set an appropriate tab order. Assign control IDs as shown in the following table.

Control	ID
Calendar control	IDC_CALENDAR1
Select Date button	IDC_SELECTDATE
Edit control	IDC_DAY
Edit control	IDC_MONTH
Edit control	IDC_YEAR
Next Week button	IDC_NEXTWEEK

Use ClassWizard to create the CActiveXDialog class. If you run ClassWizard directly from the dialog editor window, it will know that you want to create a CDialog-derived class based on the IDD_ACTIVEXDIALOG template. Simply accept the default options, and name the class CActiveXDialog.

Click on the ClassWizard Message Maps tab, and then add the message handler functions shown in the table below. To add a message handler function, click on an object ID, click on a message, and click the Add Function button. If the Add Member Function dialog box appears, type the function name and click the OK button.

Object ID	Message	Member Function
CActiveXDialog	WM_INITDIALOG	OnInitDialog (virtual function)
IDC_CALENDAR1	NewMonth (event)	OnNewMonthCalendar1
IDC_SELECTDATE	BN_CLICKED	OnSelectDate
IDC_NEXTWEEK	BN_CLICKED	OnNextWeek
IDOK	BN_CLICKED	OnOK (virtual function)

Use ClassWizard to add data members to the CActiveXDialog class. Click on the Member Variables tab, and then add the data members as shown in the illustration below.

You might think that the ClassWizard ActiveX Events tab is for mapping ActiveX control events in a container. That's not true: it's for ActiveX control developers who are defining events for a control.