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Calendar.OnVisibleMonthChanged(DateTime, DateTime) Method

  • Reference

Definition

Namespace:
System.Web.UI.WebControls
Assembly:
System.Web.dll

Raises the VisibleMonthChanged event of the Calendar control and allows you to provide a custom handler for the VisibleMonthChanged event.

C# 
protected virtual void OnVisibleMonthChanged(DateTime newDate, DateTime previousDate);

Parameters

newDate
DateTime

A DateTime that represents the month currently displayed in the Calendar.

previousDate
DateTime

A DateTime that represents the previous month displayed by the Calendar.

Examples

The following code example demonstrates how to specify and code a handler for the VisibleMonthChanged event to display whether the Calendar has moved forward or backward one month.

ASP.NET (C#) 
<%@ Page Language="C#" AutoEventWireup="True" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >

<head runat="server">
    <title> Calendar VisibleMonthChanged Example </title>
<script runat="server">

      void MonthChange(Object sender, MonthChangedEventArgs e) 
      {

         if (e.NewDate.Month > e.PreviousDate.Month)
         { 
            Message.Text = "You moved forward one month.";
         }
         else
         {
            Message.Text = "You moved backwards one month.";
         }

      }
         
   </script>
 
</head>
 
<body>
 
   <form id="form1" runat="server">

      <h3> Calendar VisibleMonthChanged Example </h3>
       
      Select a different month on the calendar. 
      <br /><br />
 
      <asp:Calendar id="Calendar1" runat="server"
           OnVisibleMonthChanged="MonthChange">

         <WeekendDayStyle BackColor="gray">
         </WeekendDayStyle>

      </asp:Calendar>

      <hr /> 

      <table border="1">

         <tr style="background-color:Silver">

            <th>

               Month navigation direction

            </th>
         </tr>

         <tr>

            <td>
           
               <asp:Label id="Message" 
                    Text="Starting month." 
                    runat="server"/>

            </td>

         </tr>

      </table>
                   
   </form>
         
</body>

</html>
ASP.NET (C#) 
<%@ Page Language="C#" AutoEventWireup="True" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >

<head runat="server">
    <title> Calendar VisibleMonthChanged Example </title>
<script runat="server">

      void MonthChange(Object sender, MonthChangedEventArgs e) 
      {

         if (e.NewDate.Month > e.PreviousDate.Month)
         { 
            Message.Text = "You moved forward one month.";
         }
         else
         {
            Message.Text = "You moved backwards one month.";
         }

      }
         
   </script>
 
</head>
 
<body>
 
   <form id="form1" runat="server">

      <h3> Calendar VisibleMonthChanged Example </h3>
       
      Select a different month on the calendar. 
      <br /><br />
 
      <asp:Calendar id="Calendar1" runat="server"
           OnVisibleMonthChanged="MonthChange">

         <WeekendDayStyle BackColor="gray">
         </WeekendDayStyle>

      </asp:Calendar>

      <hr /> 

      <table border="1">

         <tr style="background-color:Silver">

            <th>

               Month navigation direction

            </th>
         </tr>

         <tr>

            <td>
           
               <asp:Label id="Message" 
                    Text="Starting month." 
                    runat="server"/>

            </td>

         </tr>

      </table>
                   
   </form>
         
</body>

</html>

Remarks

The VisibleMonthChanged event is raised when the user clicks the next or previous month navigation elements on the title section.

Raising an event invokes the event handler through a delegate. For more information, see Handling and Raising Events.

The OnVisibleMonthChanged method also allows derived classes to handle the event without attaching a delegate. This is the preferred technique for handling the event in a derived class.

Notes to Inheritors

When overriding OnVisibleMonthChanged(DateTime, DateTime) in a derived class, be sure to call the base class's OnVisibleMonthChanged(DateTime, DateTime) method so that registered delegates receive the event.

Applies to

Product Versions
.NET Framework 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1

See also