WPF Toolkit DatePicker Month/Year Only

Question

Я использую Datepicker Toolkit как указано выше, но я хотел бы ограничить его только месяцами и годами, так как в этой ситуации пользователи не знают или не заботятся о точной дате .Когда данные хранятся в формате Datetime, будет сохранен день, но это меня не касается. Есть ли простой способ связать это?

Благодаря

Answer 1

Если вы можете использовать элемент управления Calendar вместо этого вы могли бы сделать

<toolkit:Calendar x:Name="_calendar" DisplayModeChanged="_calendar_DisplayModeChanged" DisplayMode="Year" /> 

с этим коде

Private Sub _calendar_DisplayModeChanged(ByVal sender As System.Object, ByVal e As Microsoft.Windows.Controls.CalendarModeChangedEventArgs) 

    If _calendar.DisplayMode = Microsoft.Windows.Controls.CalendarMode.Month Then 
     _calendar.DisplayMode = Microsoft.Windows.Controls.CalendarMode.Year 
    End If 

End Sub 

Answer 2

Недавно я имел специфические требования для календаря с возможностью выбора только месяц и год. Поэтому у меня есть предыдущее сообщение о пользовательском формате для датпикера wpf, но в этом случае нам нужно сделать небольшой сложный ответ. Сначала вам нужно создать специальный элемент управления следующим образом:

public class DatePickerCo : DatePicker 

Как только вы это сделаете. Существует еще один пост, когда кто-то еще, я не rememberer URL-адрес для этой должности, но в любом случае, думаю, что вам нужно перезаписать OnCalendarOpened метод так же, как это:

protected override void OnCalendarOpened(RoutedEventArgs e) 
     { 
      var popup = this.Template.FindName(
       "PART_Popup", this) as Popup; 
      if (popup != null && popup.Child is System.Windows.Controls.Calendar) 
      { 
       ((System.Windows.Controls.Calendar)popup.Child).DisplayMode = CalendarMode.Year; 
      } 

      ((System.Windows.Controls.Calendar)popup.Child).DisplayModeChanged += new EventHandler(DatePickerCo_DisplayModeChanged); 
     } 

Обратите внимание, что мы добавили последнюю строку с обработчик события DisplayModeChanged. Это действительно важно для следующих шагов. ИТАК следующий шаг определить DisplayModeChanged

private void DatePickerCo_DisplayModeChanged(object sender, CalendarModeChangedEventArgs e) 
     { 
      var popup = this.Template.FindName(
       "PART_Popup", this) as Popup; 
      if (popup != null && popup.Child is System.Windows.Controls.Calendar) 
      { 
       var _calendar = popup.Child as System.Windows.Controls.Calendar; 
       if (_calendar.DisplayMode == CalendarMode.Month) 
       { 
        _calendar.DisplayMode = CalendarMode.Year; 

        if (IsDropDownOpen) 
        { 
         this.SelectedDate = GetSelectedMonth(_calendar.DisplayDate); 
         this.IsDropDownOpen = false; 
         ((System.Windows.Controls.Calendar)popup.Child).DisplayModeChanged -= new EventHandler(DatePickerCo_DisplayModeChanged); 
        } 
       } 

      } 
     } 

private DateTime? GetSelectedMonth(DateTime? selectedDate) 
     { 
      if (selectedDate == null) 
      { 
       selectedDate = DateTime.Now; 
      } 

      int monthDifferenceStart = DateTimeHelper.CompareYearMonth(selectedDate.Value, DisplayDateRangeStart); 
      int monthDifferenceEnd = DateTimeHelper.CompareYearMonth(selectedDate.Value, DisplayDateRangeEnd); 

      if (monthDifferenceStart >= 0 && monthDifferenceEnd 0, "monthDifferenceEnd should be greater than 0!"); 
        _selectedMonth = DateTimeHelper.DiscardDayTime(DisplayDateRangeEnd); 
       } 
      } 

      return _selectedMonth; 
     } 

Здесь есть несколько вещей, сначала нужно выбрать в месяц, так что то причина для создания функции GetSelectedMonth. Во-вторых, этот метод использует класс WPFToolkit с именем DateTimeHelper.cs. Ok До сих пор мы только что создали функциональность для сбора месяца. Но как только вы нажмете на календарь месяца, мы перейдем к отображению выбранной даты в формате месяца/года. Для достижения этой цели нам нужно создать определенный стиль для нашего таможенного контроля, как это:

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

Я объяснил все о с пользовательским форматом выбора даты. Надеюсь, это поможет вам. пожалуйста, любые комментарии или предложения, вы просто дайте мне знать, привет!.

Answer 3

Спасибо @Fernando García за основу этого.

Я написал свойства DateFormat и IsMonthYear для DatePicker, чтобы включить выбор месяца/года.

Вложенное свойство IsMonthYear ограничивает Calendar DatePicker Calendar.DisplayMode в Год и Десятилетие, чтобы предотвратить выбор из CalendarMode.Month. Он также устанавливает дневную часть DatePicker.SelectedDate в 1.

Вложенное свойство DateFormat не ограничено этим сценарием, его также можно использовать отдельно от IsMonthYear, чтобы предоставить строку формата для отображения и ввода DatePicker.

Пример использования прилагаемых свойств:

<DatePicker my:DatePickerCalendar.IsMonthYear="True" 
      my:DatePickerDateFormat.DateFormat="MM/yyyy"/> 

IsMonthYear придает свойство является:

public class DatePickerCalendar 
{ 
    public static readonly DependencyProperty IsMonthYearProperty = 
     DependencyProperty.RegisterAttached("IsMonthYear", typeof(bool), typeof(DatePickerCalendar), 
              new PropertyMetadata(OnIsMonthYearChanged)); 

    public static bool GetIsMonthYear(DependencyObject dobj) 
    { 
     return (bool)dobj.GetValue(IsMonthYearProperty); 
    } 

    public static void SetIsMonthYear(DependencyObject dobj, bool value) 
    { 
     dobj.SetValue(IsMonthYearProperty, value); 
    } 

    private static void OnIsMonthYearChanged(DependencyObject dobj, DependencyPropertyChangedEventArgs e) 
    { 
     var datePicker = (DatePicker) dobj; 

     Application.Current.Dispatcher 
      .BeginInvoke(DispatcherPriority.Loaded, 
         new Action<DatePicker, DependencyPropertyChangedEventArgs>(SetCalendarEventHandlers), 
         datePicker, e); 
    } 

    private static void SetCalendarEventHandlers(DatePicker datePicker, DependencyPropertyChangedEventArgs e) 
    { 
     if (e.NewValue == e.OldValue) 
      return; 

     if ((bool)e.NewValue) 
     { 
      datePicker.CalendarOpened += DatePickerOnCalendarOpened; 
      datePicker.CalendarClosed += DatePickerOnCalendarClosed; 
     } 
     else 
     { 
      datePicker.CalendarOpened -= DatePickerOnCalendarOpened; 
      datePicker.CalendarClosed -= DatePickerOnCalendarClosed; 
     } 
    } 

    private static void DatePickerOnCalendarOpened(object sender, RoutedEventArgs routedEventArgs) 
    { 
     var calendar = GetDatePickerCalendar(sender); 
     calendar.DisplayMode = CalendarMode.Year; 

     calendar.DisplayModeChanged += CalendarOnDisplayModeChanged; 
    } 

    private static void DatePickerOnCalendarClosed(object sender, RoutedEventArgs routedEventArgs) 
    { 
     var datePicker = (DatePicker) sender; 
     var calendar = GetDatePickerCalendar(sender); 
     datePicker.SelectedDate = calendar.SelectedDate; 

     calendar.DisplayModeChanged -= CalendarOnDisplayModeChanged; 
    } 

    private static void CalendarOnDisplayModeChanged(object sender, CalendarModeChangedEventArgs e) 
    { 
     var calendar = (Calendar) sender; 
     if (calendar.DisplayMode != CalendarMode.Month) 
      return; 

     calendar.SelectedDate = GetSelectedCalendarDate(calendar.DisplayDate); 

     var datePicker = GetCalendarsDatePicker(calendar); 
     datePicker.IsDropDownOpen = false; 
    } 

    private static Calendar GetDatePickerCalendar(object sender) 
    { 
     var datePicker = (DatePicker) sender; 
     var popup = (Popup) datePicker.Template.FindName("PART_Popup", datePicker); 
     return ((Calendar) popup.Child); 
    } 

    private static DatePicker GetCalendarsDatePicker(FrameworkElement child) 
    { 
     var parent = (FrameworkElement) child.Parent; 
     if (parent.Name == "PART_Root") 
      return (DatePicker) parent.TemplatedParent; 
     return GetCalendarsDatePicker(parent); 
    } 

    private static DateTime? GetSelectedCalendarDate(DateTime? selectedDate) 
    { 
     if (!selectedDate.HasValue) 
      return null; 
     return new DateTime(selectedDate.Value.Year, selectedDate.Value.Month, 1); 
    } 
} 

И DateFormat придает свойство:

public class DatePickerDateFormat 
{ 
    public static readonly DependencyProperty DateFormatProperty = 
     DependencyProperty.RegisterAttached("DateFormat", typeof (string), typeof (DatePickerDateFormat), 
              new PropertyMetadata(OnDateFormatChanged)); 

    public static string GetDateFormat(DependencyObject dobj) 
    { 
     return (string) dobj.GetValue(DateFormatProperty); 
    } 

    public static void SetDateFormat(DependencyObject dobj, string value) 
    { 
     dobj.SetValue(DateFormatProperty, value); 
    } 

    private static void OnDateFormatChanged(DependencyObject dobj, DependencyPropertyChangedEventArgs e) 
    { 
     var datePicker = (DatePicker) dobj; 

     Application.Current.Dispatcher.BeginInvoke(
      DispatcherPriority.Loaded, new Action<DatePicker>(ApplyDateFormat), datePicker); 
    } 

    private static void ApplyDateFormat(DatePicker datePicker) 
    { 
     var binding = new Binding("SelectedDate") 
      { 
       RelativeSource = new RelativeSource {AncestorType = typeof (DatePicker)}, 
       Converter = new DatePickerDateTimeConverter(), 
       ConverterParameter = new Tuple<DatePicker, string>(datePicker, GetDateFormat(datePicker)) 
      }; 
     var textBox = GetTemplateTextBox(datePicker); 
     textBox.SetBinding(TextBox.TextProperty, binding); 

     textBox.PreviewKeyDown -= TextBoxOnPreviewKeyDown; 
     textBox.PreviewKeyDown += TextBoxOnPreviewKeyDown; 

     datePicker.CalendarOpened -= DatePickerOnCalendarOpened; 
     datePicker.CalendarOpened += DatePickerOnCalendarOpened; 
    } 

    private static TextBox GetTemplateTextBox(Control control) 
    { 
     control.ApplyTemplate(); 
     return (TextBox) control.Template.FindName("PART_TextBox", control); 
    } 

    private static void TextBoxOnPreviewKeyDown(object sender, KeyEventArgs e) 
    { 
     if (e.Key != Key.Return) 
      return; 

     /* DatePicker subscribes to its TextBox's KeyDown event to set its SelectedDate if Key.Return was 
     * pressed. When this happens its text will be the result of its internal date parsing until it 
     * loses focus or another date is selected. A workaround is to stop the KeyDown event bubbling up 
     * and handling setting the DatePicker.SelectedDate. */ 

     e.Handled = true; 

     var textBox = (TextBox) sender; 
     var datePicker = (DatePicker) textBox.TemplatedParent; 
     var dateStr = textBox.Text; 
     var formatStr = GetDateFormat(datePicker); 
     datePicker.SelectedDate = DatePickerDateTimeConverter.StringToDateTime(datePicker, formatStr, dateStr); 
    } 

    private static void DatePickerOnCalendarOpened(object sender, RoutedEventArgs e) 
    { 
     /* When DatePicker's TextBox is not focused and its Calendar is opened by clicking its calendar button 
     * its text will be the result of its internal date parsing until its TextBox is focused and another 
     * date is selected. A workaround is to set this string when it is opened. */ 

     var datePicker = (DatePicker) sender; 
     var textBox = GetTemplateTextBox(datePicker); 
     var formatStr = GetDateFormat(datePicker); 
     textBox.Text = DatePickerDateTimeConverter.DateTimeToString(formatStr, datePicker.SelectedDate); 
    } 

    private class DatePickerDateTimeConverter : IValueConverter 
    { 
     public object Convert(object value, Type targetType, object parameter, CultureInfo culture) 
     { 
      var formatStr = ((Tuple<DatePicker, string>) parameter).Item2; 
      var selectedDate = (DateTime?) value; 
      return DateTimeToString(formatStr, selectedDate); 
     } 

     public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture) 
     { 
      var tupleParam = ((Tuple<DatePicker, string>) parameter); 
      var dateStr = (string) value; 
      return StringToDateTime(tupleParam.Item1, tupleParam.Item2, dateStr); 
     } 

     public static string DateTimeToString(string formatStr, DateTime? selectedDate) 
     { 
      return selectedDate.HasValue ? selectedDate.Value.ToString(formatStr) : null; 
     } 

     public static DateTime? StringToDateTime(DatePicker datePicker, string formatStr, string dateStr) 
     { 
      DateTime date; 
      var canParse = DateTime.TryParseExact(dateStr, formatStr, CultureInfo.CurrentCulture, 
                DateTimeStyles.None, out date); 

      if (!canParse) 
       canParse = DateTime.TryParse(dateStr, CultureInfo.CurrentCulture, DateTimeStyles.None, out date); 

      return canParse ? date : datePicker.SelectedDate; 
     } 
    } 
} 

Answer 4

я перевел Саймон ответ в VB, я пишу здесь re (просьба дать ему кредиты)

Imports System.Windows.Threading 
Imports System.Windows.Controls.Primitives 
Imports System.Windows.Controls 

''' <summary>  Allows the Date Picker Calendar to select month. 
'''      Use with the attached property IsMonthYear Property. 
''' </summary> 
''' <remarks> Source : https://stackoverflow.com/questions/1798513/wpf-toolkit-datepicker-month-year-only 
'''   Author : </remarks> 
Public Class DatePickerCalendar 

Public Shared IsMonthYearProperty As DependencyProperty = DependencyProperty.RegisterAttached("IsMonthYear", GetType(System.Boolean), GetType(DatePickerCalendar), New PropertyMetadata(AddressOf OnIsMonthYearChanged)) 

Public Shared Function GetIsMonthYear(ByVal dobj As DependencyObject) As Boolean 
    Return CType(dobj.GetValue(IsMonthYearProperty), Boolean) 
End Function 

Public Shared Sub SetIsMonthYear(ByVal dobj As DependencyObject, ByVal value As Boolean) 
    dobj.SetValue(IsMonthYearProperty, value) 
End Sub 

Private Shared Sub OnIsMonthYearChanged(ByVal dobj As DependencyObject, ByVal e As DependencyPropertyChangedEventArgs) 
    Dim MyDatePicker = CType(dobj, DatePicker) 
    Application.Current.Dispatcher.BeginInvoke(DispatcherPriority.Loaded, _ 
        New Action(Of DatePicker, DependencyPropertyChangedEventArgs)(AddressOf SetCalendarEventHandlers), MyDatePicker, e) 
End Sub 

Private Shared Sub SetCalendarEventHandlers(ByVal datePicker As DatePicker, ByVal e As DependencyPropertyChangedEventArgs) 
    If (e.NewValue = e.OldValue) Then 
     Return 
    End If 
    If CType(e.NewValue, Boolean) Then 
     AddHandler datePicker.CalendarOpened, AddressOf DatePickerOnCalendarOpened 
     AddHandler datePicker.CalendarClosed, AddressOf DatePickerOnCalendarClosed 
    Else 
     RemoveHandler datePicker.CalendarOpened, AddressOf DatePickerOnCalendarOpened 
     RemoveHandler datePicker.CalendarClosed, AddressOf DatePickerOnCalendarClosed 
    End If 
End Sub 

Private Shared Sub DatePickerOnCalendarOpened(ByVal sender As Object, ByVal routedEventArgs As RoutedEventArgs) 
    Dim MyCalendar = GetDatePickerCalendar(sender) 
    MyCalendar.DisplayMode = CalendarMode.Year 
    AddHandler MyCalendar.DisplayModeChanged, AddressOf CalendarOnDisplayModeChanged 
End Sub 

Private Shared Sub DatePickerOnCalendarClosed(ByVal sender As Object, ByVal routedEventArgs As RoutedEventArgs) 
    Dim MyDatePicker = CType(sender, DatePicker) 
    Dim MyCalendar = GetDatePickerCalendar(sender) 
    MyDatePicker.SelectedDate = MyCalendar.SelectedDate 
    RemoveHandler MyCalendar.DisplayModeChanged, AddressOf CalendarOnDisplayModeChanged 
End Sub 

Private Shared Sub CalendarOnDisplayModeChanged(ByVal sender As Object, ByVal e As CalendarModeChangedEventArgs) 
    Dim MyCalendar = CType(sender, Calendar) 
    If (MyCalendar.DisplayMode <> CalendarMode.Month) Then 
     Return 
    End If 
    MyCalendar.SelectedDate = GetSelectedCalendarDate(MyCalendar.DisplayDate) 
    Dim MyDatePicker = GetCalendarsDatePicker(MyCalendar) 
    MyDatePicker.IsDropDownOpen = False 
End Sub 

Private Shared Function GetDatePickerCalendar(ByVal sender As Object) As Calendar 
    Dim MyDatePicker = CType(sender, DatePicker) 
    Dim MyPopup = CType(MyDatePicker.Template.FindName("PART_Popup", MyDatePicker), Popup) 
    Return CType(MyPopup.Child, Calendar) 
End Function 

Private Shared Function GetCalendarsDatePicker(ByVal child As FrameworkElement) As DatePicker 
    Dim MyParent = CType(child.Parent, FrameworkElement) 
    If (MyParent.Name = "PART_Root") Then 
     Return CType(MyParent.TemplatedParent, DatePicker) 
    End If 
    Return GetCalendarsDatePicker(MyParent) 
End Function 

Private Shared Function GetSelectedCalendarDate(ByVal selectedDate As DateTime?) As DateTime? 
    If Not selectedDate.HasValue Then 
     Return Nothing 
    End If 
    Return New DateTime(selectedDate.Value.Year, selectedDate.Value.Month, 1) 
End Function 
End Class 

Но для класса формата я не мог заставить его работать.
Я использовал и slighlty модифицировал (более простой) ответ от petrycol за месяц/год дисплей. Источник:
Changing the string format of the WPF DatePicker

<DatePicker SelectedDate="{Binding FromDate}" 
        l:DatePickerCalendar.IsMonthYear="True" 
        x:Name="MonthCalendar" HorizontalAlignment="Center"     
       > 
     <DatePicker.Resources> 
      <!--Source : https://stackoverflow.com/questions/3819832/changing-the-string-format-of-the-wpf-datepicker 
       Author : petrycol --> 
      <Style TargetType="{x:Type DatePickerTextBox}"> 
       <Setter Property="Control.Template"> 
        <Setter.Value> 
         <ControlTemplate> 
          <TextBox Width="60" TextAlignment="Center" x:Name="PART_TextBox" 
            Text="{Binding Path=SelectedDate, StringFormat='MM yy', 
            RelativeSource={RelativeSource AncestorType={x:Type DatePicker}},FallbackValue='-- --'}" /> 
         </ControlTemplate> 
        </Setter.Value> 
       </Setter> 
      </Style> 
     </DatePicker.Resources> 
     <!--CalendarOpened="DatePicker_CalendarOpened"--> 
    </DatePicker> 

Answer 5

Чтобы добавить Simon's brilliant answer, я сделал некоторые изменения в DatePickerDateFormat.cs, чтобы предотвратить ошибку, когда Textbox мгновение мерцает между дд/мм/гггг (оригинальный формат строки) и MM/yyyy (формат переопределенной строки).

Это происходит из-за того, что DatePicker автоматически устанавливает текст PART_Textbox непосредственно перед раскрытием. Он устанавливает его в текст, отформатированный в строке, и вы можете сделать что-то, что вы можете сделать, - это переопределит вашу привязку.

Чтобы предотвратить это, я добавил этот код к DatePickerDateFormat class from above.

1. в ApplyDateFormat, получить кнопку раскрывающийся и обрабатывать PreviewMouseUp

   private static void ApplyDateFormat(DatePicker datePicker) 
   { 
       var binding = new Binding("SelectedDate") 
           { 
            RelativeSource = new RelativeSource { AncestorType = typeof(DatePicker) }, 
            Converter = new DatePickerDateTimeConverter(), 
            ConverterParameter = new Tuple<DatePicker, string>(datePicker, GetDateFormat(datePicker)), 
            StringFormat = GetDateFormat(datePicker) // This is also new but didnt seem to help 
           }; 
   
       var textBox = GetTemplateTextBox(datePicker); 
       textBox.SetBinding(TextBox.TextProperty, binding); 
   
       textBox.PreviewKeyDown -= TextBoxOnPreviewKeyDown; 
       textBox.PreviewKeyDown += TextBoxOnPreviewKeyDown; 
   
       var dropDownButton = GetTemplateButton(datePicker); 
   
       datePicker.CalendarOpened -= DatePickerOnCalendarOpened; 
       datePicker.CalendarOpened += DatePickerOnCalendarOpened; 
   
       // Handle Dropdownbutton PreviewMouseUp to prevent issue of flickering textboxes 
       dropDownButton.PreviewMouseUp -= DropDownButtonPreviewMouseUp; 
       dropDownButton.PreviewMouseUp += DropDownButtonPreviewMouseUp; 
   } 
   
   private static ButtonBase GetTemplateButton(DatePicker datePicker) 
   { 
       return (ButtonBase)datePicker.Template.FindName("PART_Button", datePicker); 
   } 
   

Когда PreviewMouseUp пожары, если есть выбранная дата, переопределения На Dropdown Показано поведение (мы имитировать все, что Datepicker делает, но мы не ставим PART_TextBox текст)

/// <summary> 
    ///  Prevents a bug in the DatePicker, where clicking the Dropdown open button results in Text being set to default formatting regardless of StringFormat or binding overrides 
    /// </summary> 
    private static void DropDownButtonPreviewMouseUp(object sender, MouseButtonEventArgs e) 
    { 
     var fe = sender as FrameworkElement; 
     if (fe == null) return; 

     var datePicker = fe.TryFindAncestorOrSelf<DatePicker>(); 
     if (datePicker == null || datePicker.SelectedDate == null) return;    

     var dropDownButton = GetTemplateButton(datePicker); 

     // Dropdown button was clicked 
     if (e.OriginalSource == dropDownButton && datePicker.IsDropDownOpen == false) 
     {         
      // Open dropdown 
      datePicker.SetCurrentValue(DatePicker.IsDropDownOpenProperty, true); 

      // Mimic everything else in the standard DatePicker dropdown opening *except* setting textbox value 
      datePicker.SetCurrentValue(DatePicker.DisplayDateProperty, datePicker.SelectedDate.Value); 

      // Important otherwise calendar does not work 
      dropDownButton.ReleaseMouseCapture(); 

      // Prevent datePicker.cs from handling this event 
      e.Handled = true;     
     } 
    } 

где EXTENS ионный метод TryFindAncestorOrSelf просматривает визуальное дерево, чтобы найти объект типа T. Вы можете найти его реализацию здесь: http://www.hardcodet.net/2008/02/find-wpf-parent

Надеюсь, это поможет кому-то!

Answer 6

Это сочетание Simon's и Dr. ABT's ответов, включая все дополнительный требуемый код и с эталонными конфликтами между Windows и Microsoft управлением фиксированным.

Это довольно смешно, что для этого требуется класс из 345 строк, но он должен работать, если вы включите DatePickerCalendar.cs (с вашим пространством имен), создайте свой проект и используйте следующий XAML.

<DatePicker local:DatePickerCalendar.IsMonthYear="True" 
      local:DatePickerDateFormat.DateFormat="MMM-yyyy" 
      Text="MMM-yyyy"></DatePicker> 

DatePickerCalendar.cs

using System; 
using System.Globalization; 
using System.Windows; 
using System.Windows.Controls; 
using System.Windows.Controls.Primitives; 
using System.Windows.Data; 
using System.Windows.Input; 
using System.Windows.Media; 
using System.Windows.Threading; 
using Calendar = System.Windows.Controls.Calendar; 
using CalendarMode = System.Windows.Controls.CalendarMode; 
using CalendarModeChangedEventArgs = System.Windows.Controls.CalendarModeChangedEventArgs; 
using DatePicker = System.Windows.Controls.DatePicker; 

namespace <YourProject> 
{ 
    public class DatePickerCalendar 
    { 
     public static readonly DependencyProperty IsMonthYearProperty = 
      DependencyProperty.RegisterAttached("IsMonthYear", typeof(bool), typeof(DatePickerCalendar), 
               new PropertyMetadata(OnIsMonthYearChanged)); 

     public static bool GetIsMonthYear(DependencyObject dobj) 
     { 
      return (bool)dobj.GetValue(IsMonthYearProperty); 
     } 

     public static void SetIsMonthYear(DependencyObject dobj, bool value) 
     { 
      dobj.SetValue(IsMonthYearProperty, value); 
     } 

     private static void OnIsMonthYearChanged(DependencyObject dobj, DependencyPropertyChangedEventArgs e) 
     { 
      var datePicker = (DatePicker)dobj; 

      Application.Current.Dispatcher 
       .BeginInvoke(DispatcherPriority.Loaded, 
          new Action<DatePicker, DependencyPropertyChangedEventArgs>(SetCalendarEventHandlers), 
          datePicker, e); 
     } 

     private static void SetCalendarEventHandlers(DatePicker datePicker, DependencyPropertyChangedEventArgs e) 
     { 
      if (e.NewValue == e.OldValue) 
       return; 

      if ((bool)e.NewValue) 
      { 
       datePicker.CalendarOpened += DatePickerOnCalendarOpened; 
       datePicker.CalendarClosed += DatePickerOnCalendarClosed; 
      } 
      else 
      { 
       datePicker.CalendarOpened -= DatePickerOnCalendarOpened; 
       datePicker.CalendarClosed -= DatePickerOnCalendarClosed; 
      } 
     } 

     private static void DatePickerOnCalendarOpened(object sender, RoutedEventArgs routedEventArgs) 
     { 
      var calendar = GetDatePickerCalendar(sender); 
      calendar.DisplayMode = CalendarMode.Year; 

      calendar.DisplayModeChanged += CalendarOnDisplayModeChanged; 
     } 

     private static void DatePickerOnCalendarClosed(object sender, RoutedEventArgs routedEventArgs) 
     { 
      var datePicker = (DatePicker)sender; 
      var calendar = GetDatePickerCalendar(sender); 
      datePicker.SelectedDate = calendar.SelectedDate; 

      calendar.DisplayModeChanged -= CalendarOnDisplayModeChanged; 
     } 

     private static void CalendarOnDisplayModeChanged(object sender, CalendarModeChangedEventArgs e) 
     { 
      var calendar = (Calendar)sender; 
      if (calendar.DisplayMode != CalendarMode.Month) 
       return; 

      calendar.SelectedDate = GetSelectedCalendarDate(calendar.DisplayDate); 

      var datePicker = GetCalendarsDatePicker(calendar); 
      datePicker.IsDropDownOpen = false; 
     } 

     private static Calendar GetDatePickerCalendar(object sender) 
     { 
      var datePicker = (DatePicker)sender; 
      var popup = (Popup)datePicker.Template.FindName("PART_Popup", datePicker); 
      return ((Calendar)popup.Child); 
     } 

     private static DatePicker GetCalendarsDatePicker(FrameworkElement child) 
     { 
      var parent = (FrameworkElement)child.Parent; 
      if (parent.Name == "PART_Root") 
       return (DatePicker)parent.TemplatedParent; 
      return GetCalendarsDatePicker(parent); 
     } 

     private static DateTime? GetSelectedCalendarDate(DateTime? selectedDate) 
     { 
      if (!selectedDate.HasValue) 
       return null; 
      return new DateTime(selectedDate.Value.Year, selectedDate.Value.Month, 1); 
     } 
    } 

    public class DatePickerDateFormat 
    { 
     public static readonly DependencyProperty DateFormatProperty = 
      DependencyProperty.RegisterAttached("DateFormat", typeof(string), typeof(DatePickerDateFormat), 
               new PropertyMetadata(OnDateFormatChanged)); 

     public static string GetDateFormat(DependencyObject dobj) 
     { 
      return (string)dobj.GetValue(DateFormatProperty); 
     } 

     public static void SetDateFormat(DependencyObject dobj, string value) 
     { 
      dobj.SetValue(DateFormatProperty, value); 
     } 

     private static void OnDateFormatChanged(DependencyObject dobj, DependencyPropertyChangedEventArgs e) 
     { 
      var datePicker = (DatePicker)dobj; 

      Application.Current.Dispatcher.BeginInvoke(
       DispatcherPriority.Loaded, new Action<DatePicker>(ApplyDateFormat), datePicker); 
     } 
     private static void ApplyDateFormat(DatePicker datePicker) 
     { 
      var binding = new Binding("SelectedDate") 
      { 
       RelativeSource = new RelativeSource { AncestorType = typeof(DatePicker) }, 
       Converter = new DatePickerDateTimeConverter(), 
       ConverterParameter = new Tuple<DatePicker, string>(datePicker, GetDateFormat(datePicker)), 
       StringFormat = GetDateFormat(datePicker) // This is also new but didnt seem to help 
      }; 

      var textBox = GetTemplateTextBox(datePicker); 
      textBox.SetBinding(TextBox.TextProperty, binding); 

      textBox.PreviewKeyDown -= TextBoxOnPreviewKeyDown; 
      textBox.PreviewKeyDown += TextBoxOnPreviewKeyDown; 

      var dropDownButton = GetTemplateButton(datePicker); 

      datePicker.CalendarOpened -= DatePickerOnCalendarOpened; 
      datePicker.CalendarOpened += DatePickerOnCalendarOpened; 

      // Handle Dropdownbutton PreviewMouseUp to prevent issue of flickering textboxes 
      dropDownButton.PreviewMouseUp -= DropDownButtonPreviewMouseUp; 
      dropDownButton.PreviewMouseUp += DropDownButtonPreviewMouseUp; 
     } 

     private static ButtonBase GetTemplateButton(DatePicker datePicker) 
     { 
      return (ButtonBase)datePicker.Template.FindName("PART_Button", datePicker); 
     } 


     /// <summary> 
     ///  Prevents a bug in the DatePicker, where clicking the Dropdown open button results in Text being set to default formatting regardless of StringFormat or binding overrides 
     /// </summary> 
     private static void DropDownButtonPreviewMouseUp(object sender, MouseButtonEventArgs e) 
     { 
      var fe = sender as FrameworkElement; 
      if (fe == null) return; 

      var datePicker = fe.TryFindParent<DatePicker>(); 
      if (datePicker == null || datePicker.SelectedDate == null) return; 

      var dropDownButton = GetTemplateButton(datePicker); 

      // Dropdown button was clicked 
      if (e.OriginalSource == dropDownButton && datePicker.IsDropDownOpen == false) 
      { 
       // Open dropdown 
       datePicker.SetCurrentValue(DatePicker.IsDropDownOpenProperty, true); 

       // Mimic everything else in the standard DatePicker dropdown opening *except* setting textbox value 
       datePicker.SetCurrentValue(DatePicker.DisplayDateProperty, datePicker.SelectedDate.Value); 

       // Important otherwise calendar does not work 
       dropDownButton.ReleaseMouseCapture(); 

       // Prevent datePicker.cs from handling this event 
       e.Handled = true; 
      } 
     } 



     private static TextBox GetTemplateTextBox(Control control) 
     { 
      control.ApplyTemplate(); 
      return (TextBox)control?.Template?.FindName("PART_TextBox", control); 
     } 

     private static void TextBoxOnPreviewKeyDown(object sender, KeyEventArgs e) 
     { 
      if (e.Key != Key.Return) 
       return; 

      /* DatePicker subscribes to its TextBox's KeyDown event to set its SelectedDate if Key.Return was 
      * pressed. When this happens its text will be the result of its internal date parsing until it 
      * loses focus or another date is selected. A workaround is to stop the KeyDown event bubbling up 
      * and handling setting the DatePicker.SelectedDate. */ 

      e.Handled = true; 

      var textBox = (TextBox)sender; 
      var datePicker = (DatePicker)textBox.TemplatedParent; 
      var dateStr = textBox.Text; 
      var formatStr = GetDateFormat(datePicker); 
      datePicker.SelectedDate = DatePickerDateTimeConverter.StringToDateTime(datePicker, formatStr, dateStr); 
     } 

     private static void DatePickerOnCalendarOpened(object sender, RoutedEventArgs e) 
     { 
      /* When DatePicker's TextBox is not focused and its Calendar is opened by clicking its calendar button 
      * its text will be the result of its internal date parsing until its TextBox is focused and another 
      * date is selected. A workaround is to set this string when it is opened. */ 

      var datePicker = (DatePicker)sender; 
      var textBox = GetTemplateTextBox(datePicker); 
      var formatStr = GetDateFormat(datePicker); 
      textBox.Text = DatePickerDateTimeConverter.DateTimeToString(formatStr, datePicker.SelectedDate); 
     } 

     private class DatePickerDateTimeConverter : IValueConverter 
     { 
      public object Convert(object value, Type targetType, object parameter, CultureInfo culture) 
      { 
       var formatStr = ((Tuple<DatePicker, string>)parameter).Item2; 
       var selectedDate = (DateTime?)value; 
       return DateTimeToString(formatStr, selectedDate); 
      } 

      public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture) 
      { 
       var tupleParam = ((Tuple<DatePicker, string>)parameter); 
       var dateStr = (string)value; 
       return StringToDateTime(tupleParam.Item1, tupleParam.Item2, dateStr); 
      } 

      public static string DateTimeToString(string formatStr, DateTime? selectedDate) 
      { 
       return selectedDate.HasValue ? selectedDate.Value.ToString(formatStr) : null; 
      } 

      public static DateTime? StringToDateTime(DatePicker datePicker, string formatStr, string dateStr) 
      { 
       DateTime date; 
       var canParse = DateTime.TryParseExact(dateStr, formatStr, CultureInfo.CurrentCulture, 
                 DateTimeStyles.None, out date); 

       if (!canParse) 
        canParse = DateTime.TryParse(dateStr, CultureInfo.CurrentCulture, DateTimeStyles.None, out date); 

       return canParse ? date : datePicker.SelectedDate; 
      } 


     } 

    } 



    public static class FEExten 
    { 
     /// <summary> 
     /// Finds a parent of a given item on the visual tree. 
     /// </summary> 
     /// <typeparam name="T">The type of the queried item.</typeparam> 
     /// <param name="child">A direct or indirect child of the 
     /// queried item.</param> 
     /// <returns>The first parent item that matches the submitted 
     /// type parameter. If not matching item can be found, a null 
     /// reference is being returned.</returns> 
     public static T TryFindParent<T>(this DependencyObject child) 
      where T : DependencyObject 
     { 
      //get parent item 
      DependencyObject parentObject = GetParentObject(child); 

      //we've reached the end of the tree 
      if (parentObject == null) return null; 

      //check if the parent matches the type we're looking for 
      T parent = parentObject as T; 
      if (parent != null) 
      { 
       return parent; 
      } 
      else 
      { 
       //use recursion to proceed with next level 
       return TryFindParent<T>(parentObject); 
      } 
     } 

     /// <summary> 
     /// This method is an alternative to WPF's 
     /// <see cref="VisualTreeHelper.GetParent"/> method, which also 
     /// supports content elements. Keep in mind that for content element, 
     /// this method falls back to the logical tree of the element! 
     /// </summary> 
     /// <param name="child">The item to be processed.</param> 
     /// <returns>The submitted item's parent, if available. Otherwise 
     /// null.</returns> 
     public static DependencyObject GetParentObject(this DependencyObject child) 
     { 
      if (child == null) return null; 

      //handle content elements separately 
      ContentElement contentElement = child as ContentElement; 
      if (contentElement != null) 
      { 
       DependencyObject parent = ContentOperations.GetParent(contentElement); 
       if (parent != null) return parent; 

       FrameworkContentElement fce = contentElement as FrameworkContentElement; 
       return fce != null ? fce.Parent : null; 
      } 

      //also try searching for parent in framework elements (such as DockPanel, etc) 
      FrameworkElement frameworkElement = child as FrameworkElement; 
      if (frameworkElement != null) 
      { 
       DependencyObject parent = frameworkElement.Parent; 
       if (parent != null) return parent; 
      } 

      //if it's not a ContentElement/FrameworkElement, rely on VisualTreeHelper 
      return VisualTreeHelper.GetParent(child); 
     } 
    } 
} 

Скриншот