Introduction
While working on a freelance project recently (last month), I needed a basic month-view calendar control to use in a few places in the app. I searched, and found Creating an Outlook Calendar using WPF (by rudigobbler), which was a great day-view. I also found Richard Gavel's excellent on-going (I hope) work on Creating the Outlook UI with WPF (it's a 7-part series, so far).
Both of these are more serious efforts to create real, reusable components for other developers - but neither had a month-view. I was also in a time-crunch, as usual, and didn't really want to pay $800+ for a suite of WPF tools from one of the vendors. Since I really needed just very basic functionality, I took an afternoon and wrote this one.
Background
This article assumes you have a basic understanding of .NET and WPF. The code is not complicated, nor is it long. I make use of lambda functions (System.Predicate) in order to find appointments for each day, but that's about as complicated as it gets. Note that this requires .NET Framework 3.x - I built it on 3.5 SP1.
Using the code
The sample app (see download at top) shows the basic use of the calendar. Note that in Window1.xaml, I only include a reference to the local assembly, like so:
xmlns:cal="clr-namespace:QuickWPFMonthCalendar"
Window1.xaml only contains one line of markup between the Window open and closing tags:
<cal:MonthView x:Name="AptCalendar" VerticalAlignment="Stretch"
VerticalContentAlignment="Stretch"/>
This is Window1.xaml in Visual Studio 2008's design mode. As you can see, using it is pretty simple:
The MonthView control exposes several events, which are declared in MonthView.xaml.vb like this:
Public Event DisplayMonthChanged(ByVal e As MonthChangedEventArgs)
Public Event DayBoxDoubleClicked(ByVal e As NewAppointmentEventArgs)
Public Event AppointmentDblClicked(ByVal Appointment_Id As Integer)
I used two custom EventArgs structures, MonthChangedEventArgs and NewAppointmentEventArgs. This was mainly because I'm using other information in the application I built; you could just pass a date, or an ID, or an actual appointment object.
To handle the events, just write an event handler as you would for any control. In the sample app's Window1.xaml.vb, I used the following:
Private Sub DayBoxDoubleClicked_event(ByVal e As NewAppointmentEventArgs) _
Handles AptCalendar.DayBoxDoubleClicked
MessageBox.Show("You double-clicked on day " & _
CDate(e.StartDate).ToShortDateString(), _
"Calendar Event", MessageBoxButton.OK)
End Sub
Private Sub AppointmentDblClicked(ByVal Appointment_Id As Integer) _
Handles AptCalendar.AppointmentDblClicked
MessageBox.Show("You double-clicked on appointment with ID = " & _
Appointment_Id, "Calendar Event", MessageBoxButton.OK)
End Sub
Private Sub DisplayMonthChanged(ByVal e As MonthChangedEventArgs) _
Handles AptCalendar.DisplayMonthChanged
Call SetAppointments()
End Sub
In the actual application I created this for, the Appointment class was generated by Visual Studio's LINQ-to-SQL designer, and it has more fields and functionality. For this demo, I stripped out everything LINQ-specific. MonthView stores appointments as a List(Of Appointment), which you set using the property MonthAppointments (ideally, you only pass the appointments the calendar needs to show that month). In this demo, I have a loop in the Window's Loaded event that creates appointments on 50 random days during the current year, and I pass only a filtered list (using List(Of T).FindAll) to MonthAppointments.
Also, note that setting the MonthAppointments property will automatically redraw the calendar to show the currently selected month. There is one other public property, DisplayStartDate (of type Date), which is used to determine the month and year to show (the day and time are ignored). Setting DisplayStartDate does not (possibly confusingly) cause the calendar to re-render with that month; this is because in my app, I always set some appointments (even if I assign an empty List(Of Appointment) to MonthAppointments).
Finally, there is a label that shows the currently-displayed month and year, plus forward and back-buttons, which update DisplayStartDate, and then raise the DisplayMonthChanged event.
Points of interest
In order to tell where a user has double-clicked (since it could be on an appointment, or in the blank part of a daybox control), I repurposed a function that I'm using in another part of the app, which was originally in C# and comes from Bea Stollnitz's blog.
Also - I included a small check in the code in MonthView.xaml.vb that shows some random appointments in design mode - this was so I could see what the appointments looked like without having to build/run. That code block looks like this:
If System.ComponentModel.DesignerProperties.GetIsInDesignMode(Me) Then
If Microsoft.VisualBasic.Rnd(1) < 0.25 Then
Dim apt As New DayBoxAppointmentControl()
apt.DisplayText.Text = "Apt on " & i & "th"
dayBox.DayAppointmentsStack.Children.Add(apt)
End If
ElseIf ....
Obviously, you can safely take that out.
Keep in mind that this month view was a quick & dirty solution to a problem, and it definitely has some flaws. One main flaw is that if you have too many appointments in one day, they don't fit, and don't give you any visual cue. Also, it's all done with XAML building blocks, although you could grab the intermediate-built *.xaml.g.vb files and create a new project with all code, or just build it to a DLL and then reference it. As of now, it doesn't support styles, or anything else fancy - I'm just learning WPF as I do this project.
Hopefully, this rather ugly effort will prompt an expert in WPF to create a more full-featured and style-able control that we can all then use!
History
- Version 0.1 - Posted March 11, 2009 (created in Feb. 2009) by Kirk Davis.
