CODEWITHSUNDEEP
c#windows-runtimeuwp
AbsoluteSith
AbsoluteSith

Reputation: 1967

How to clear the date bound to a CalendarDatePicker if certain conditions occur in UWP?

I have a CalendarDatePicker whose Date property is bound to a converter. I don't want it to show the date if the date is default(01-01-0001)

My code

class DateTimeToCalendarDateTimeOffsetConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, string language)
    {
        try
        {
            DateTime date = (DateTime)value;
            return new DateTimeOffset(date);
        }
        catch (Exception ex)
        {
            return null;
        }
    }

    public object ConvertBack(object value, Type targetType, object parameter, string language)
    {
        try
        {
            DateTimeOffset dto = (DateTimeOffset)value;
            return dto.DateTime;
        }
        catch (Exception ex)
        {
            return DateTime.MinValue;
        }
    }
}

But by default it set's todays date. What value can I set to clear the date?

Upvotes: 0

Views: 520

Answers (1)

Grace Feng
Grace Feng

Reputation: 16652

From the discussion we had earlier, I think you wanted to set the the Date of the CalendarDatePicker according to the value which is got from a server, but at first this value is set to "0001-01-01" by default.

So you can do it like this:

<Page.Resources>
    <local:DateTimeToCalendarDateTimeOffsetConverter x:Key="cvt" />
</Page.Resources>

<Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
    <CalendarDatePicker x:Name="picker" Date="{x:Bind Path=dateTime,Converter={StaticResource cvt}, Mode=TwoWay}" />
</Grid>

code behind:

private DateTime dateTime;

public MainPage()
{
    this.InitializeComponent();
    dateTime = new DateTime(0001, 01, 01);
}

This variable dateTime is fake by me and is set in the code behind, and the converter is like this:

public class DateTimeToCalendarDateTimeOffsetConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, string language)
    {
        var date = (DateTime)value;
        if (date == new DateTime(0001, 01, 01))
        {
            return null;
        }
        return new DateTimeOffset?(date);
    }

    public object ConvertBack(object value, Type targetType, object parameter, string language)
    {
        var dto = (DateTimeOffset)value;
        return dto.DateTime;
    }
}

But be aware that the Date is constrained by MinDate and MaxDate, if Date is smaller than MinDate, the value is set to MinDate. If the Date is greater than MaxDate, the value is set to MaxDate. So if you set the date here for example "0010-01-02", and your MinDate is set to "2000-01-01", when return this date in your Converter, the CalendarDatePicker will show "01/01/2000".

For more information about this control, you can refer to CalendarDatePicker class.

Upvotes: 1

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