How to change format (e.g. dd/MMM/yyyy) of DateTimePicker in WPF application

Question

I want to Change the Format of date selected in DateTimePicker in WPF Application

Answer 1

In XAML:

<toolkit:DatePicker SelectedDateFormat="Long" />

or

<toolkit:DatePicker SelectedDateFormat="Short" />

Answer 2

Add this style to your xaml or App.xaml file

 <Style TargetType="{x:Type DatePickerTextBox}">
     <Setter Property="VerticalContentAlignment" Value="Center"/>
     <Setter Property="Control.Template">
         <Setter.Value>
             <ControlTemplate>
                 <TextBox x:Name="PART_TextBox"
            Text="{Binding Path=SelectedDate, StringFormat='dd.MM.yyyy', 
            RelativeSource={RelativeSource AncestorType={x:Type DatePicker}}}" />
             </ControlTemplate>
         </Setter.Value>
     </Setter>
 </Style>

Answer 3

As for me, changing environment to change DatePicker format (like Thread.CurrentCulture) is not a good idea. Sure, you can create Control derived from DatePicker and implement dependency property like Format, but this costs too much effort.

Simple and elegant solution I found is binding value not to SelectedDate itself, but to some unused property (I used ToolTip property for this) and update this property when SelectedDate is changed.

C# implementation for one-way binding looks like this:

    DatePicker datePicker = new DatePicker();
    datePicker.SetBinding(ToolTipProperty, "Date");
    datePicker.SelectedDateChanged += (s, ea) =>
        {
            DateTime? date = datePicker.SelectedDate;
            string value = date != null ? date.Value.ToString("yyyy-MM-dd") : null;
            datePicker.ToolTip = value;
        };

XAML+C# should look like this:

XAML:

<DatePicker ToolTip="{Binding Date Mode=TwoWay}"
            SelectedDateChanged="DatePicker_SelectedDateChanged"/>

C#:

private void DatePicker_SelectedDateChanged(object sender, EventArgs ea)
{
    DatePicker datePicker = (DatePicker)sender;
    DateTime? date = datePicker.SelectedDate;
    string value = date != null ? date.Value.ToString("yyyy-MM-dd") : null;
    datePicker.ToolTip = value;
}

For two-way implementation handle ToolTipChanged event the same way to update SelectedDate.