An MS Outlook-style mini-calendar control using WTL

Sample Image

Introduction

This article explains an MS Outlook-style mini-calendar control using WTL.

This began as a port of Matt Gullett's MS Outlook-style miniature calendar control written for MFC. There are still some features remaining to be added to it, but it serves as a reasonable starting point for anyone needing this functionality in a WTL application.

Features

Display months in n-columns by m-rows
Single-date or date-range selection (including SHIFT-extended selection)
Different fonts for: header, day initials, and day numbers
Auto-repeat on scroll arrows
Auto-scroll when previous/following months' days are selected
Callback (via WM_NOTIFY) for highlighting 'special days'
Month-year selection from header popup (with drop shadow under XP)

Optional display styles include:

3D border
Today's date highlighted
Previous/following months' days displayed with the months' days
Week can start on any day of the week

Environment

This control was developed using VC++ .NET, WTL 7, and the Feb 2003 Platform SDK. It has been tested under Windows XP only.

History

22 May 2003
- Initial release
6 June 2003
- Added month/year selection popup
- Added 'special date' highlighting
Soon...?
- Buttons (optional) for selecting today's date, and for clearing the selection
- Provide internationalisation support
- Make it an ActiveX component

Acknowledgements

Matt Gullett - MSOutlook style miniature calendar control written for MFC
Bjarke Viksoe - atlgdix.h (used for flicker-free drawing)

License

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here

About the Author

Tony Ioanides

Web Developer

Australia

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Use this C++ in VB project

Blackboss

2:43 9 May '06

All, Is there a way to use this control in a vb project?
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compile error

humbird

1:06 27 Jun '05

Hello, what am I doing wrong? I got 'WTL::CIconT' : template class has already been defined error during compilation
Sign In·View Thread·Permalink	1.29/5 (6 votes)

Bug in SetRange(...)

vschoech

0:48 5 Jul '04

Hi,

I ran into a bug in SetRange(...) and probably elsewhere in the MiniCalendarCtrl code. It is silently assumed that given times are always integral days (hours==0 && minutes==0 && seconds==0). If this is not the case, the behaviour is not as expected.

I suggest the following fix, applying an explicit round to the time values that are passed as parameters:

void
CMiniCalendarCtrl::SetRange(const COleDateTime& dateAnchor, const COleDateTime& dateSelect)
{
	ATLASSERT( dateAnchor.GetStatus()==COleDateTime::valid );	
	ATLASSERT( dateSelect.GetStatus()==COleDateTime::valid );	
	m_dtAnchor = floor(dateAnchor);
	m_dtSelect = floor(dateSelect);
	NotifySelChanged();
	Invalidate();
}

Regards,
V.

Re: Bug in SetRange(...)

Tony Ioanides

12:58 5 Jul '04

Given that the control is a calendar control (ie. deals only with dates), date-times are used internally with the time part always set to 00:00:00. Any method that violates this constraint will introduce a bug. Also, the SetRange(...) method doesn't exist in the supplied code. You suggested it as an enhancement, remember?! Check your post.
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Re: Bug in SetRange(...)

vschoech

23:40 5 Jul '04

Ooops. you're right. My bug. Sorry! :-/
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Forcing NotifyGetSpecialDays()

vschoech

1:31 13 Jan '04

I'm reusing the same instance of the Ctrl for multiple purposes. When switching from one context to another, I would like to force the Ctrl to update the special days.

Therefore I added the following public method:

void
CMiniCalendarCtrl::UpdateSpecialDays()
{
    NotifyGetSpecialDays();
}

Is this a consistent extension or are there potential problems with triggering the Special Days message this way? Is there a better way to inject new special days?
V.

Re: Forcing NotifyGetSpecialDays()

Tony Ioanides

22:54 14 Jan '04

Your suggestion is exactly the right thing to do. By design, the control only caches enough state to support the view. It is the clients responsibility to track special days beyond the range of months displayed.
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Bug ResetRange()/NotifySelChanged()?

vschoech

1:23 13 Jan '04

Hi,

I like the Ctrl very much, but there seems to be a minor issue with calling ResetRange(). m_dtAnchor is invalidated, but it is then used in a comparison operation in NotifySelChanged(). This triggers a Debug assertion, comparison of invalid dates is not allowed.

I am calling ResetRange() even when the user has not yet made any selection. Maybe this is part of the problem?

Would you like to provide a fix?
V.

Re: Bug ResetRange()/NotifySelChanged()?

Tony Ioanides

23:21 14 Jan '04

Its not your call to ResetRange() thats the problem - its my bug I'll put a fix up soon but for those that can't wait, in NotifySelChanged change the line: `if (m_bMultiSelEnabled)` to: `if (m_bMultiSelEnabled && m_dtAnchor.GetStatus() == COleDateTime::valid)` Thanks for the feedback.
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Re: Bug ResetRange()/NotifySelChanged()?

vschoech

0:07 15 Jan '04

Tony, it is nice to see that you are still interested in your own code. Smile | :)

While you are at it, preparing an update: I have another question/suggestion regarding CMiniCalendarCtrl::ResetRange(). What is the intended semantics of this method? From the name I would infer that a call to ResetRange actually resets the Ctrl to its pre-user-interaction state. But this is not the case, even after calling ResetRange() there is still a selection visible in the Ctrl.

To achieve clearance of the entire selection, I extended the method as follows:

BOOL
CMiniCalendarCtrl::ResetRange()
{
	if (m_dtAnchor.GetStatus() == COleDateTime::valid)
	{
		m_dtAnchor.SetStatus(COleDateTime::invalid);
		m_dtSelect.SetStatus(COleDateTime::invalid);
		NotifySelChanged();
 
		Invalidate();
		return TRUE;
	}
	
	m_dtAnchor.SetStatus(COleDateTime::invalid);
	m_dtSelect.SetStatus(COleDateTime::invalid);
	return FALSE;
}

If this is not what ResetRange() was meant to do, then what is it? ResetRange() is called twice from inside your own code, in CMiniCalendarCtrl::OnLButtonDown(UINT nFlags, CPoint point) and in CMiniCalendarCtrl::ApplyStyle(DWORD dwStyle). I'm not sure if my changes are consistent with your use of the method in these places. Some quick testing suggests that they are.

Moreover, I added another public method that allows to prepare the range with some default selection before the user is displayed the Ctrl (or even change selection on the fly):

void
CMiniCalendarCtrl::SetRange(const COleDateTime& dateAnchor, const COleDateTime& dateSelect)
{
	ATLASSERT( dateAnchor.GetStatus()==COleDateTime::valid );	
	ATLASSERT( dateSelect.GetStatus()==COleDateTime::valid );	
	m_dtAnchor = dateAnchor;
	m_dtSelect = dateSelect;
	NotifySelChanged();
	Invalidate();
}

Just for review or as a suggestion...
Thanks a lot!
Volker

Good work.

Matt Gullett

0:51 7 Jun '03

This looks really good. Thanks for giving me credit where appropriate. Matt Gullett
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Wow this is just what I have been doing the last few weeks!

Angus Comber

13:43 4 Jun '03

Hello

I have been writing an ATL control pretty much like this based on the Month Calendar common control.

Didn't get as far as you have but have code for highlighting (making bold) / unhighlighting days in month. and possibly some other things - would need to review yours more. I am happy to share code - just ask.

I would be able to review much quicker if you had created a VC6 project! So I will see if I can get going in my VC6 environment.

Angus Comber
angus@iteloffice.com

Hans J. Schroeder

11:41 26 May '03

Compared to the comctl calendar this one is a ten. Thanks! Hans J. Schroeder - Microlog GmbH - www.microlognet.com - Home of the Cabinet Manager
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