Calendar controls are indispensable tools for web applications that involve date selection, scheduling, and event management. They empower users to visually interact with dates and times in a user-friendly manner. In this guide, we’ll explore the key properties that govern the appearance, behavior, and functionality of calendar controls, particularly in the context of ASP.NET.

Fundamental Properties

• SelectedDate: This property represents the currently selected date on the calendar. You can programmatically set or retrieve this value to manage the user’s date selection.
• VisibleDate: Controls the month and year currently displayed on the calendar. You can change this to allow users to navigate through different months or years.
• SelectionMode: Determines how users can select dates. Options include:
  • Day: Single day selection
  • DayWeek: Single day or entire week selection
  • DayWeekMonth: Single day, week, or entire month selection
  • None: Disables date selection
• FirstDayOfWeek: Sets the first day of the week (e.g., Sunday or Monday).
• ShowGridLines: Controls whether grid lines are displayed around the day cells.
• ShowDayHeader: Determines if the day names (e.g., Mon, Tue, Wed) are shown at the top of the calendar.
• ShowTitle: Controls the visibility of the calendar title (month and year).
• ShowNextPrevMonth: Determines whether navigation controls for moving to the next or previous month are displayed.

Appearance Customization

• DayNameFormat: Specifies how day names are formatted (e.g., “M,” “Mon,” “Monday”).
• TitleFormat: Controls the format of the calendar title (month and year).
• TodaysDate: Highlights the current date on the calendar.
• OtherMonthDayStyle, WeekendDayStyle, SelectedDayStyle, etc.: These properties allow you to customize the appearance of specific types of days using CSS classes or inline styles.

Advanced Properties

• SelectedDates: Allows multiple date selections.
• DayRender: An event that lets you customize the rendering of each day cell programmatically.
• VisibleMonthChanged: An event triggered when the user navigates to a different month.

ASP.NET Calendar Control Specifics

• Calendar.SelectedDate: Gets or sets the currently selected date.
• Calendar.VisibleDate: Gets or sets the month currently displayed.
• Calendar.SelectionMode: Determines how users select dates.
• Calendar.NextPrevFormat: Controls the format of the next/previous month navigation links.

Example: Customizing a Calendar in ASP.NET

Code snippet

<asp:Calendar ID=”Calendar1″ runat=”server”

              SelectionMode=”DayWeek”

              FirstDayOfWeek=”Monday”

              TodaysDate=”<%# DateTime.Today %>”

              DayNameFormat=”Shortest”>

    <SelectedDayStyle BackColor=”#FFFF99″ />

</asp:Calendar>

In this example, we create a calendar that allows selecting a day or a week, starts the week on Monday, highlights today’s date, uses short day names (“M,” “T,” etc.), and applies a yellow background to the selected day(s).

Key Takeaways

• Calendar control properties give you fine-grained control over how the calendar looks and behaves.
• You can customize the appearance of specific days using CSS or events.
• Server-side events like DayRender and VisibleMonthChanged enable dynamic calendar modifications.