DatePicker.DateValidationError Event

public:
 event EventHandler<System::Windows::Controls::DatePickerDateValidationErrorEventArgs ^> ^ DateValidationError;

public event EventHandler<System.Windows.Controls.DatePickerDateValidationErrorEventArgs> DateValidationError;

member this.DateValidationError : EventHandler<System.Windows.Controls.DatePickerDateValidationErrorEventArgs> 

Public Custom Event DateValidationError As EventHandler(Of DatePickerDateValidationErrorEventArgs) 

Public Event DateValidationError As EventHandler(Of DatePickerDateValidationErrorEventArgs) 

Event Type

Examples

The following example creates a DatePicker that displays the dates in August 2009 and specifies that each Saturday and Sunday is not selectable.

DatePicker datePickerWithBlackoutDates = new DatePicker();

datePickerWithBlackoutDates.DisplayDateStart = new DateTime(2009, 8, 1);
datePickerWithBlackoutDates.DisplayDateEnd = new DateTime(2009, 8, 31);
datePickerWithBlackoutDates.SelectedDate = new DateTime(2009, 8, 10);

datePickerWithBlackoutDates.BlackoutDates.Add(
 new CalendarDateRange(new DateTime(2009, 8, 1), new DateTime(2009, 8, 2)));
datePickerWithBlackoutDates.BlackoutDates.Add(
 new CalendarDateRange(new DateTime(2009, 8, 8), new DateTime(2009, 8, 9)));
datePickerWithBlackoutDates.BlackoutDates.Add(
 new CalendarDateRange(new DateTime(2009, 8, 15), new DateTime(2009, 8, 16)));
datePickerWithBlackoutDates.BlackoutDates.Add(
 new CalendarDateRange(new DateTime(2009, 8, 22), new DateTime(2009, 8, 23)));
datePickerWithBlackoutDates.BlackoutDates.Add(
 new CalendarDateRange(new DateTime(2009, 8, 29), new DateTime(2009, 8, 30)));

datePickerWithBlackoutDates.DateValidationError +=
 new EventHandler<DatePickerDateValidationErrorEventArgs>(DatePicker_DateValidationError);

// root is a Panel that is defined elsewhere.
root.Children.Add(datePickerWithBlackoutDates);

Dim datePickerWithBlackoutDates As New DatePicker()

datePickerWithBlackoutDates.DisplayDateStart = New DateTime(2009, 8, 1)
datePickerWithBlackoutDates.DisplayDateEnd = New DateTime(2009, 8, 31)
datePickerWithBlackoutDates.SelectedDate = New DateTime(2009, 8, 10)

datePickerWithBlackoutDates.BlackoutDates.Add( _
 New CalendarDateRange(New DateTime(2009, 8, 1), New DateTime(2009, 8, 2)))

datePickerWithBlackoutDates.BlackoutDates.Add( _
 New CalendarDateRange(New DateTime(2009, 8, 8), New DateTime(2009, 8, 9)))

datePickerWithBlackoutDates.BlackoutDates.Add( _
 New CalendarDateRange(New DateTime(2009, 8, 15), New DateTime(2009, 8, 16)))

datePickerWithBlackoutDates.BlackoutDates.Add( _
 New CalendarDateRange(New DateTime(2009, 8, 22), New DateTime(2009, 8, 23)))

datePickerWithBlackoutDates.BlackoutDates.Add( _
 New CalendarDateRange(New DateTime(2009, 8, 29), New DateTime(2009, 8, 30)))

AddHandler datePickerWithBlackoutDates.DateValidationError, _
 AddressOf DatePicker_DateValidationError

' root is a Panel that is defined elsewhere. 
root.Children.Add(datePickerWithBlackoutDates)

<DatePicker Name="datePickerWithBlackoutDates"
 DisplayDateStart="8/1/09"
 DisplayDateEnd="8/31/09"
 SelectedDate="8/10/09"
 DateValidationError="DatePicker_DateValidationError">
 <DatePicker.BlackoutDates>
 <CalendarDateRange Start="8/1/09" End="8/2/09"/>
 <CalendarDateRange Start="8/8/09" End="8/9/09"/>
 <CalendarDateRange Start="8/15/09" End="8/16/09"/>
 <CalendarDateRange Start="8/22/09" End="8/23/09"/>
 <CalendarDateRange Start="8/29/09" End="8/30/09"/>
 </DatePicker.BlackoutDates>
</DatePicker>

The DatePicker handles the DateValidationError event, as shown in the following code. If the user enters a date that is not selectable, the example displays a message. If the user enters text that is not a valid date, an exception is thrown.

// If the text is a valid date, but a part of the 
// BlackoutDates collection, show a message.
// If the text is not a valid date, thow an exception.
private void DatePicker_DateValidationError(object sender,
 DatePickerDateValidationErrorEventArgs e)
{
 DateTime newDate;
 DatePicker datePickerObj = sender as DatePicker;

 if (DateTime.TryParse(e.Text, out newDate))
 {
 if (datePickerObj.BlackoutDates.Contains(newDate))
 {
 MessageBox.Show(String.Format("The date, {0}, cannot be selected.",
 e.Text));
 }
 }
 else
 {
 e.ThrowException = true;
 }
}

' If the text is a valid date, but a part of the 
' BlackoutDates collection, show a message. 
' If the text is not a valid date, thow an exception. 
Private Sub DatePicker_DateValidationError(ByVal sender As Object, _
 ByVal e As DatePickerDateValidationErrorEventArgs)

 Dim newDate As DateTime
 Dim datePickerObj As DatePicker = TryCast(sender, DatePicker)

 If DateTime.TryParse(e.Text, newDate) Then
 If datePickerObj.BlackoutDates.Contains(newDate) Then
 MessageBox.Show([String].Format("The date, {0}, cannot be selected.", e.Text))
 End If
 Else
 e.ThrowException = True
 End If
End Sub

Remarks

After the DateValidationError event occurs, if you set the DatePickerDateValidationErrorEventArgs.ThrowException property to true, one of the following exceptions is raised:

XAML Attribute Usage

<DatePicker DateValidationError="eventhandler"/>