DatePicker.DateValidationError Event

Definition

Namespace:

System.Windows.Controls

Assembly:

PresentationFramework.dll

Occurs when Text is set to a value that cannot be interpreted as a date or when the date cannot be selected.

C#

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

Event Type

EventHandler<DatePickerDateValidationErrorEventArgs>

Examples

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

C#

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);

XAML

<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.

C#

// 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;
    }
}

Remarks

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

Exception type	Condition
FormatException	The text entered cannot be parsed to a valid date, and the exception is not suppressed.
ArgumentOutOfRangeException	The text entered parses to a date that is not selectable.

XAML Attribute Usage

<DatePicker DateValidationError="eventhandler"/>

Applies to