Home

Windows Controls: The Month/Calendar Control

 

Fundamentals of the Month Calendar Control

 

Introduction

To assist you with displaying date values or requesting dates from a user, the .NET Framework provides a control named month calendar or simply a calendar:

The Month Calendar control

The dates used and the way they display are based on the Regional Settings of the Control Panel. It may also depend on the operating system. The title bar of the control displays two buttons and one label. The left button allows the user to select the previous value depending on the type that is displaying on the label (month, year, decade, or century). The user does this by clicking the left button. By default, the label displays the currently selected month and the year. The right button is used to get to the next value (month, year, decade, or century, depending on the value on the label).

Under the title bar, the short names of week days display, using the format set in the Windows Control Panel. In US English, the first day is usually Sun for Sunday. The first day can be changed by the programmer. On the control, the currently selected date is highlighted. In the main area, the numeric days of the month display on a white background (this color and any color on the control can be changed). To select a date, the user can click it in the list.

By default, the calendar opens with today's day highlighted. Using the buttons of the title bar, the month-year label, the user can change the date. If at one time the month calendar is displaying a date other than today, and if the user wants to return to today's date, he or she can:

  • Click the bottom label that displays Today (you as the programmer can hide the Today label if you want)
  • Right-click anywhere on the control and click Go To Today

The Month Calendar control allowing the user to select a year

If the month calendar displays regularly (with a month, a year, the week days, and the days of a month), if the user clicks the label that is between the buttons, the month calendar displays a list of 12 months from January to December, and the month of the date that was previously selected is highlighted. Here is an example:

The Month Calendar control allowing the user to select a year

If the month calendar is displaying a list of months:

  • To select a month, the user can click it
  • To get the 12 months of the previous year, the user can click the left button
  • To get the 12 months of the next year, the user can click the right button

If the month calendar is displaying the names of months and if the user clicks the year, the label would display a decade of the current year and the 9th year from it. The body of the month calendar would display the years in that decade, plus the year prior to that decade and the year after that decade:

The Month Calendar control allowing the user to select a year

That display has new options:

  • To select a year, the user can click it
  • To get a list of the previous 12 years, the user can click the left button
  • To get a list of the next 12 years, the user can click the right button

If the month calendar is displaying the numbers of 12 years and if the user clicks the label, the label would display a century from the current year and the 99th year from it. The body of the month calendar would display 12 labels that each shows a decade:

The Month Calendar control allowing the user to select a year

This time:

  • To select a decade, the user can click it
  • To get a list of the previous decades, the user can click the left button
  • To get a list of the next decades, the user can click the right button

The calendar can be configured to display more than one month. You have many options. You can display the months horizontally:

The Month Calendar control displaying two months

Or you can display them vertically:

The Month Calendar control displaying two months

If the control is displaying more than one month, the buttons would increment or decrement by the previous or next value (month, year, decade, or century) in the list. For example, if the control is displaying April and May and if the user clicks the left button, the control would display March and April. If the control is displaying April and May and if the user clicks the right button, the control would display May and June.

Creating a Month Calendar

The month calendar control is based on the MonthCalendar class, which is based on the Control class. To create a month calendar, declare a variable or type MonthCalendar and add it to the Controls collection of its container. Here is an example:

open System
open System.Windows.Forms

let exercise : Form = new  System.Windows.Forms.Form()
exercise.Text <- "Exercise"

let mcExercise : MonthCalendar = new MonthCalendar()
exercise.Controls.Add mcExercise

Application.Run exercise
 
   
 
 

 

 

Introductory Characteristics of a Month Calendar

   

Introduction

A month calendar is primarily a Windows control. It gets it primary properties from the Control class. Based on this, when creating it, you can specify its location, its size, and other characteristics.

When the user clicks the month calendar, one date is selected. As mentioned in our description, you can give the control the ability to display more than one month. To make this possible, when visually creating the control, set its width to have enough space. In the same way, you can increase the height to display many months. This allows you to display as many months as you judge necessary. Here is an example:

Month Calendar

To make it a highly visual object, the month calendar uses different colors to represent the background, week days, the background of the title bar, the text of the title bar, the text of the days of the previous month, and the text of the days of the next month.

Selecting a Date

As mentioned in our description, the calendar control displays the days of a selected month. The control also displays the remaining days, if any, of the last week of the previous month; that is, the days of the previous month that share the week with the first day of the first week of the selected month. The control also displays the first days of the next month that share the week with the last day of the current month.

To use the calendar control, the user can click a date, whether it is a date from the current month or a day of the other (previous and next) months. When the user has clicked a date to select it, the control fires a DateSelected event. The DateSelected event is of type DateRangeEventArgs.

The user can also select a date using the keyboard. To do this, the user must first give focus to the control. This is possible by pressing Tab continuously until the control receives focus (or by clicking any date on the control). To select a date using the keyboard, the user can continually press one of the arrow keys (on the keyboard) until the desired date is selected.

You too can programmatically select a date on the calendar control. To do this, assign a valid DateTime value to both the SelectionStart and the SelectionEnd properties. Here is an example:

open System
open System.Drawing
open System.Windows.Forms

let exercise : Form = new  System.Windows.Forms.Form()
exercise.Text <- "Month Calendar"

let btnSelectDate = new Button()
btnSelectDate.Location <- new Point(12, 12)
btnSelectDate.Text <- "Select Date"
exercise.Controls.Add btnSelectDate

let mcExercise : MonthCalendar = new MonthCalendar()
mcExercise.Location <- new Point(12, 44)
exercise.Controls.Add mcExercise

let btnSelectDateClicked e =
    mcExercise.SelectionStart <- new DateTime(1988, 12, 5)
    mcExercise.SelectionEnd <- new DateTime(1988, 12, 5)

btnSelectDate.Click.Add btnSelectDateClicked
Application.Run exercise

Month Calendar

When a date has been selected, whether by the user (using the mouse or the keyboard) or by you (through code), the control fires a DateChanged event. The DateChanged event is of type DateRangeEventArgs.

The DateRangeEventArgs class is equipped with two properties: Start and End. When the user clicks a date, these two properties hold the date that was clicked. This means that you can use either of these properties to know the date that was clicked. Both the Start and the End properties are of type DateTime.

Showing Today

The calendar control is used to let the user know today's date in two ways. On the calendar, today's date is circled by an almost hand-drawn ellipse. In the bottom section of the calendar, today's date is also displayed as a sentence. If you want to display or hide the bottom label, set the ShowToday Boolean property accordingly. For example, to hide it, set this property to false. The presence or absence of this ellipse is controlled by the ShowTodayCircle Boolean property whose default value is true. If you set this property to false, today's date would appear without the ellipse:

Calendar

When a new calendar control is added to an application, it assumes today's date. If you want to change this date, use the TodayDate property.

Bold Dates

To accentuate the importance of one or more days of a month, you can bold some days. To create the list of dates, create an array of DateTime values (each member of the array must be a recognizable DateTime value). Once the array is ready, assign it to the BoldDates property.

If you prefer the months bolded, assign the array to the MonthlyBoldedDates property.

The Date Range Selection

When the user clicks the calendar control, one date is selected. As mentioned in our description, you can give the control the ability to display more than one month. To make this possible, when creating the control, set its width to have enough space. In the same way, you can increase the height to display many months.

The user can select a range of dates using the keyboard or using a combination of the mouse and the keyboard. To do this, the user must first give focus to the control. To select a range of dates using the keyboard, the user can press and hold Shift, then press one of the arrow keys continually until the last date of the desired range is selected (in reality, we will see that there is a property that controls the maximum range of dates that can be selected). To select a range of dates using a combination of the mouse and keyboard, the user can click the first date, press and hold Shift, then click the last date.

After selecting the days, the starting date is stored in the SelectionStart property. The last date of the selection is stored in the SelectionEnd property. Both properties are of DateTime type. The range of the selected dates is stored in a SelectionRange value. SelectionRange is simply a class that can give you information about the beginning and the end of a selected range of dates.

To programmatically select a date, assign the starting to the SelectionStart property and assign the last date to the SelectionEnd property.

By default, the user can select only up to 7 days at a time. If you want, you can let the user be able to select more or less days than that. If you configure the control to display more than one month, the user can select days from one month to another as long as the days are in a range.

After selecting a range of dates, the control fires a DateChanged event, which is of type DateRangeEventArgs. We saw earlier that the DateRangeEventArgs class has two properties. The DateRangeEventArgs.Start property holds the starting date of the range that the user made. The DateRangeEventArgs.End holds the last date from the range that the user made.

The Maximum Date Range Selection

To control the number of days you want the user to be able to select, change the value of the MaxSelectionCount property. The user cannot select more days than the MaxSelectionCount value but the user can select less.

The Colorful Characteristics of a Month Calendar Control

 

Introduction

To make it a highly visual object, a month calendar control uses different colors to represent the background, week days, the background of the title bar, the text of the title bar, the text of the days of the previous month, and the text of the days of the next month.

To change a color, access its property name in code and assign the desired , whether by name or using its RGB value.

The Background Color of the Title Bar

As mentioned already, the top section of the calendar control displays buttons and labels. By default, these are positioned on top of a blue background. The background color of this section is controlled by the TitleBackColor property. Here is an example of changing it:

open System
open System.Drawing
open System.Windows.Forms

let exercise : Form = new  System.Windows.Forms.Form()
exercise.Text <- "Month Calendar"

let mcExercise : MonthCalendar = new MonthCalendar()
mcExercise.Location <- new Point(12, 12)

mcExercise.TitleBackColor <- Color.FromArgb(192, 0, 0)

exercise.Controls.Add mcExercise

Application.Run exercise

Calendar

The Font Color of the Title Bar

By default, the labels on the title bar display in a white color defined by the ActiveCaptionText system color. The color used to paint the text of the labels of the title bar is controlled by the TitleForeColor property. Here is an example of changing it:

open System
open System.Drawing
open System.Windows.Forms

let exercise : Form = new  System.Windows.Forms.Form()
exercise.Text <- "Month Calendar"

let mcExercise : MonthCalendar = new MonthCalendar()
mcExercise.Location <- new Point(12, 12)

mcExercise.TitleBackColor <- Color.FromArgb(192, 0, 0)
mcExercise.TitleForeColor <- Color.Yellow

exercise.Controls.Add mcExercise

Application.Run exercise

Calendar

The Minimum and Maximum Dates

As mentioned already, to change the month and subsequently the year of the calendar, the user can click the buttons continuously. By default, the user can navigate from 1/1/1753 to 12/31/9998. If you want to limit the allowable dates beyond which the user should not navigate, use the MinDate and the MaxDate properties. 

The First Day of the Week

Under the title bar, the short names weekdays display, using the format set in Control Panel. In US English, the first day is usually Sunday. If you want to start with a different day, set the value using the FirstDayOfWeek property. The names of weekdays use the same color as the TitleBackColor property. Under the names of the week, there is a horizontal line used as the separator. By default, this line separator is painted in black but it uses the same color as the numeric values of the days of the selected month.

The Background Color of the Calendar

Under the line separator, the numeric days of the month are listed. By default, the numeric days of the control display above a white background which is the Window system color. This color is controlled by the overridden BackColor property.

Calendar

The Font Color of the Days of the Current Month

Calendar The numbers of the days of the month display in two colors. The real days of the selected month display, by default, in a black color as the WindowText system color. The color of these days is controlled by the overridden ForeColor property.

The Font Color of the Days of the Trailing Months

Besides the days of the currently selected month, the calendar control also displays one or more days of the previous month and one or more days of the subsequent month. These are referred to as trailing months or trailing days. These are dayts that don't belong to the currently selected month. These days display in a different color controlled by the TrailingForeColor property. By default, this color is set to GrayText:

Calendar

Of course, you can programmatically change these colors. Although any color is allowed in any category, you should make sure that the calendar is still reasonably appealing and usable.

 
 
   
 

Home Copyright © 2014-2015 FunctionX Home