Calendar.OnVisibleMonthChanged(DateTime, DateTime) Metodo
Definizione
Importante
Alcune informazioni sono relative alla release non definitiva del prodotto, che potrebbe subire modifiche significative prima della release definitiva. Microsoft non riconosce alcuna garanzia, espressa o implicita, in merito alle informazioni qui fornite.
Genera l'evento VisibleMonthChanged del controllo Calendar e consente di fornire un gestore personalizzato per l'evento VisibleMonthChanged.
protected:
virtual void OnVisibleMonthChanged(DateTime newDate, DateTime previousDate);protected virtual void OnVisibleMonthChanged (DateTime newDate, DateTime previousDate);abstract member OnVisibleMonthChanged : DateTime * DateTime -> unit
override this.OnVisibleMonthChanged : DateTime * DateTime -> unitProtected Overridable Sub OnVisibleMonthChanged (newDate As DateTime, previousDate As DateTime)Parametri
- newDate
- DateTime
Oggetto DateTime che rappresenta il mese correntemente visualizzato nell'oggetto Calendar.
- previousDate
- DateTime
Oggetto DateTime che rappresenta il mese precedente visualizzato dall'oggetto Calendar.
Esempio
Nell'esempio di codice seguente viene illustrato come specificare e codice un gestore per visualizzare se l'evento VisibleMonthChangedCalendar è stato spostato avanti o indietro un mese.
<%@ 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>
<%@ Page Language="VB" 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">
Sub MonthChange(sender As Object, e As MonthChangedEventArgs)
If e.NewDate.Month > e.PreviousDate.Month Then
Message.Text = "You moved forward one month."
Else
Message.Text = "You moved backwards one month."
End If
End Sub
</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>
<%@ 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>
<%@ Page Language="VB" 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">
Sub MonthChange(sender As Object, e As MonthChangedEventArgs)
If e.NewDate.Month > e.PreviousDate.Month Then
Message.Text = "You moved forward one month."
Else
Message.Text = "You moved backwards one month."
End If
End Sub
</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>
Commenti
L'evento VisibleMonthChanged viene generato quando l'utente fa clic sugli elementi di spostamento del mese successivo o precedente nella sezione titolo.
Quando viene generato un evento, il gestore dell'evento viene richiamato tramite un delegato. Per altre informazioni, vedere la gestione e generazione di eventi.
Il metodo OnVisibleMonthChanged consente inoltre alle classi derivate di gestire l'evento senza associare un delegato. È la tecnica consigliata per la gestione dell'evento in una classe derivata.
Note per gli eredi
Quando si esegue l'override di OnVisibleMonthChanged(DateTime, DateTime) in una classe derivata, verificare di chiamare il metodo OnVisibleMonthChanged(DateTime, DateTime) della classe di base in modo che i delegati registrati ricevano l'evento.
