Wpf Calendar изменение CalendarItem

в общем допилил проект не кликабельнная отображалка диапазонов для месяца с доп информацией. Связь элементов календаря получилось сделать только через мультибиндинг и конверторы. в общем как-то так.

XAML

<UserControl x:Class="YearClendar.MonthCalendar.MonthCalendar"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             xmlns:local="clr-namespace:YearClendar.MonthCalendar"
             xmlns:Convert="clr-namespace:MonthCalendar.Converters"
             xmlns:helpers="clr-namespace:MonthCalendar.Helpers"             
             mc:Ignorable="d" 
             d:DesignHeight="300" d:DesignWidth="300" >
    <UserControl.Resources>
        <Convert:NumberDateConverter x:Key="NumberDateConverter"/>
        <Convert:NeedShowBack x:Key="NeedShowBack"/>
        <Convert:BackgroundItemConverter x:Key="BackgroundItemConverter"/>
        <Convert:NumForeItemConverter x:Key="NumForeItemConverter"/>     
        <Style x:Key="CalendarStyle_2" TargetType="{x:Type Calendar}">
            <Setter Property="Foreground" Value="#FF333333"/>
            <Setter Property="Background">
                <Setter.Value>
                    <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
                        <GradientStop Color="#FFE4EAF0" Offset="0"   />
                        <GradientStop Color="#FFECF0F4" Offset="0.16"/>
                        <GradientStop Color="#FFFCFCFD" Offset="0.16"/>
                        <GradientStop Color="#FFFFFFFF" Offset="1"   />
                    </LinearGradientBrush>
                </Setter.Value>
            </Setter>
            <Setter Property="BorderBrush">
                <Setter.Value>
                    <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
                        <GradientStop Color="#FFA3AEB9" Offset="0"/>
                        <GradientStop Color="#FF8399A9" Offset="0.375"/>
                        <GradientStop Color="#FF718597" Offset="0.375"/>
                        <GradientStop Color="#FF617584" Offset="1"/>
                    </LinearGradientBrush>
                </Setter.Value>
            </Setter>
            <Setter Property="BorderThickness" Value="1"/>
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="{x:Type Calendar}">
                        <StackPanel x:Name="PART_Root" HorizontalAlignment="Center">
                            <CalendarItem x:Name="PART_CalendarItem" 
                                          BorderBrush="{TemplateBinding BorderBrush}" 
                                          BorderThickness="{TemplateBinding BorderThickness}" 
                                          Background="{TemplateBinding Background}" 
                                          Style="{TemplateBinding CalendarItemStyle}"/>
                        </StackPanel>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
        <Style x:Key="CalendarButtonStyle_2" TargetType="{x:Type CalendarButton}">
            <Setter Property="Background" Value="#FFBADDE9"/>
            <Setter Property="MinWidth" Value="40"/>
            <Setter Property="MinHeight" Value="42"/>
            <Setter Property="FontSize" Value="10"/>
            <Setter Property="HorizontalContentAlignment" Value="Center"/>
            <Setter Property="VerticalContentAlignment" Value="Center"/>
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="{x:Type CalendarButton}">
                        <Grid>                          
                            <ContentPresenter x:Name="NormalText" TextElement.Foreground="#FF000000" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="1,0,1,1" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>                            
                        </Grid>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
        <Style x:Key="CalendarItemStyle_2" TargetType="{x:Type CalendarItem}">
            <Setter Property="Margin" Value="0,1,0,1"/>
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="{x:Type CalendarItem}">
                        <ControlTemplate.Resources>
                            <DataTemplate x:Key="{x:Static CalendarItem.DayTitleTemplateResourceKey}">
                                <TextBlock Foreground="#FF000000" FontWeight="Bold" FontSize="9.5" 
                                           FontFamily="Verdana" HorizontalAlignment="Center" Margin="0,2,0,2" 
                                           Text="{Binding}" VerticalAlignment="Center"/>
                            </DataTemplate>
                        </ControlTemplate.Resources>
                        <Grid x:Name="PART_Root">
                            <Grid.Resources>
                                <SolidColorBrush x:Key="DisabledColor" Color="#A5FFFFFF"/>
                            </Grid.Resources>
                            <VisualStateManager.VisualStateGroups>
                                <VisualStateGroup x:Name="CommonStates">
                                    <VisualState x:Name="Normal"/>
                                    <VisualState x:Name="Disabled">
                                        <Storyboard>
                                            <DoubleAnimation Duration="0" To="1" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="PART_DisabledVisual"/>
                                        </Storyboard>
                                    </VisualState>
                                </VisualStateGroup>
                            </VisualStateManager.VisualStateGroups>
                            <Border BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" CornerRadius="1">
                                <Border BorderBrush="#FFFFFFFF" BorderThickness="2" CornerRadius="1">
                                    <Grid>
                                        <Grid.Resources>
                                        </Grid.Resources>
                                        <Grid.ColumnDefinitions>
                                            <ColumnDefinition Width="Auto"/>
                                            <ColumnDefinition Width="Auto"/>
                                            <ColumnDefinition Width="Auto"/>
                                        </Grid.ColumnDefinitions>
                                        <Grid.RowDefinitions>
                                            <RowDefinition Height="Auto"/>
                                            <RowDefinition Height="*"/>
                                        </Grid.RowDefinitions>
                                        <TextBlock 
                                                   Grid.Column="1" 
                                                   FontWeight="Bold"
                                                   Focusable="False" 
                                                   FontSize="10.5" 
                                             Foreground="Black"
                                                   HorizontalAlignment="Stretch" 
                                                   TextAlignment="Center" 
                                                   Grid.Row="0" 
                                                   VerticalAlignment="Stretch"
                                            Text="{Binding ElementName=PART_HeaderButton,Path=Content}" Margin="0" Width="Auto"
                                            />
                                        <Button x:Name="PART_HeaderButton" Grid.Column="1" FontWeight="Bold" Visibility="Collapsed" FontSize="10.5" HorizontalAlignment="Center" Grid.Row="0"   VerticalAlignment="Center"/>
                                        <Grid x:Name="PART_MonthView" Grid.ColumnSpan="3" HorizontalAlignment="Center" Margin="1,-1,1,1" Grid.Row="1" Visibility="Visible">
                                            <Grid.ColumnDefinitions>
                                                <ColumnDefinition Width="Auto"/>
                                                <ColumnDefinition Width="Auto"/>
                                                <ColumnDefinition Width="Auto"/>
                                                <ColumnDefinition Width="Auto"/>
                                                <ColumnDefinition Width="Auto"/>
                                                <ColumnDefinition Width="Auto"/>
                                                <ColumnDefinition Width="Auto"/>
                                            </Grid.ColumnDefinitions>
                                            <Grid.RowDefinitions>
                                                <RowDefinition Height="Auto"/>
                                                <RowDefinition Height="Auto"/>
                                                <RowDefinition Height="Auto"/>
                                                <RowDefinition Height="Auto"/>
                                                <RowDefinition Height="Auto"/>
                                                <RowDefinition Height="Auto"/>
                                                <RowDefinition Height="Auto"/>
                                            </Grid.RowDefinitions>
                                        </Grid>
                                    </Grid>
                                </Border>
                            </Border>
                            <Rectangle x:Name="PART_DisabledVisual" Fill="{StaticResource DisabledColor}" Opacity="0" RadiusY="2" RadiusX="2" Stretch="Fill" Stroke="{StaticResource DisabledColor}" StrokeThickness="1" Visibility="Collapsed"/>
                        </Grid>
                        <ControlTemplate.Triggers>
                            <Trigger Property="IsEnabled" Value="False">
                                <Setter Property="Visibility" TargetName="PART_DisabledVisual" Value="Visible"/>
                            </Trigger>
                            <DataTrigger Binding="{Binding DisplayMode, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Calendar}}}" Value="Year">
                                <Setter Property="Visibility" TargetName="PART_MonthView" Value="Hidden"/>
                            </DataTrigger>
                            <DataTrigger Binding="{Binding DisplayMode, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Calendar}}}" Value="Decade">
                                <Setter Property="Visibility" TargetName="PART_MonthView" Value="Hidden"/>
                            </DataTrigger>
                        </ControlTemplate.Triggers>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
        <ControlTemplate x:Key="ButtonControlTemplate_2" TargetType="{x:Type Button}">
            <ContentPresenter x:Name="buttonContent" ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" TextElement.Foreground="#FF333333" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="0" VerticalAlignment="{TemplateBinding VerticalContentAlignment}">
            </ContentPresenter>
        </ControlTemplate>
        <Style x:Key="CalendarDayButtonStyle_2" TargetType="{x:Type CalendarDayButton}">
            <Setter Property="MinWidth" Value="5"/>
            <Setter Property="MinHeight" Value="5"/>
            <Setter Property="FontSize" Value="16"/>
            <Setter Property="Height" Value="25"/>
            <Setter Property="Width" Value="25"/>
            <Setter Property="HorizontalContentAlignment" Value="Center"/>
            <Setter Property="VerticalContentAlignment" Value="Center"/>
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="{x:Type CalendarDayButton}">
                        <Grid >
                            <Grid.Resources>
                                <helpers:BindingProxy x:Key="proxy" Data="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type local:MonthCalendar}}, Path=DataContext}" />
                            </Grid.Resources>
                            <Border BorderThickness="1" BorderBrush="DarkGray"/>
                            <Rectangle x:Name="AccentBackground" RadiusX="1" RadiusY="1" Opacity="0.3" IsHitTestVisible="False">
                                <Rectangle.Fill>
                                    <MultiBinding  Converter="{StaticResource BackgroundItemConverter}">
                                        <MultiBinding.Bindings>
                                            <Binding />
                                            <Binding Source="{StaticResource proxy}" Path="Data.SelectedDays"/>
                                        </MultiBinding.Bindings>
                                    </MultiBinding>
                                </Rectangle.Fill>
                                <Rectangle.Visibility>
                                    <MultiBinding Converter="{StaticResource NeedShowBack}">
                                        <MultiBinding.Bindings>
                                            <Binding />
                                            <Binding Source="{StaticResource proxy}" Path="Data.SelectedDays"/>                                                                                        
                                        </MultiBinding.Bindings>
                                    </MultiBinding>
                                </Rectangle.Visibility>
                            </Rectangle>

                            <Label x:Name="NormalText" TextElement.Foreground="#FF000000" 
                                                       Padding="0" 
                                                       Margin="5,1,2,1" 
                                                       TextElement.FontSize="11"
                                              Content="{Binding Day}"
                                              HorizontalAlignment="Right"
                                              VerticalAlignment="Bottom"/>

                            <Label x:Name="UpName" FontSize="9" 
                                   Padding="2,0,0,0"     
                                   BorderThickness="1"
                                   VerticalAlignment="Top"
                                   HorizontalAlignment="Left">
                                <Label.Foreground>
                                    <MultiBinding Converter="{StaticResource NumForeItemConverter}">
                                        <MultiBinding.Bindings>
                                            <Binding />
                                            <Binding  Source="{StaticResource proxy}" Path="Data.SelectedDays"/>                                          
                                        </MultiBinding.Bindings>
                                    </MultiBinding>
                                </Label.Foreground>
                                <MultiBinding Converter="{StaticResource NumberDateConverter}">
                                    <MultiBinding.Bindings>
                                        <Binding />
                                        <Binding  Source="{StaticResource proxy}" Path="Data.SelectedDays"/>
                                    </MultiBinding.Bindings>
                                </MultiBinding>
                                <Label.Style>
                                    <Style TargetType="{x:Type Label}">
                                        <Setter Property="BorderBrush" Value="Gray"/>
                                        <Style.Triggers>
                                            <Trigger Property="Content" Value="{x:Null}">
                                                <Setter Property="BorderBrush" Value="Transparent"/>
                                            </Trigger>
                                        </Style.Triggers>
                                            </Style>
                                </Label.Style>
                            </Label>
                        </Grid>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
    </UserControl.Resources>
    <Grid>

класс модель

namespace MonthCalendar.Model
{
   public class MonthModel : BaseModel
    {
        private DateTime p_DisplayDate;
         private DateTime m_OldDisplayDate;
        Dictionary<DateTime, SelectDayElemet> _SelectedDays;
       public Dictionary<DateTime, SelectDayElemet> SelectedDays
        {
            get { return _SelectedDays; }
            set {
                  _SelectedDays =value;
                  OnPropertyChanged(()=>SelectedDays);
                }
        }
        public void Update()
        {
            OnPropertyChanged(() => SelectedDays);
              OnPropertyChanged(() => DisplayDate);
            OnPropertyChanged(() => DisplayDateStart);
            OnPropertyChanged(() => DisplayDateEnd);
        }
        public MonthModel()
        {
            this.Initialize();
        }
        public event EventHandler RefreshRequested;
        private void RequestRefresh()
        {
            RefreshRequested?.Invoke(this, new EventArgs());
        }

        public DateTime DisplayDate
        {
            get { return GetFirstDay(); }
            set
            {
                WorkMonth = value;
                GetFirstDay();
                OnPropertyChanged(() => DisplayDate);
            }
        }
        DateTime GetFirstDay()
        {
            DateTime tmp1 = new DateTime(WorkMonth.Year, WorkMonth.Month, 1);
            return new DateTime(WorkMonth.Year, WorkMonth.Month, 1);
        }
        DateTime GetLastDay()
        {
            if (WorkMonth.Month==12)
                return new DateTime(WorkMonth.Year, WorkMonth.Month, 31);
            DateTime tmp2 = new DateTime(WorkMonth.Year, WorkMonth.Month + 1, 1);
            DateTime tmp3 = tmp2.AddDays(-1);
            return new DateTime(tmp3.Year, tmp3.Month, tmp3.Day);
        }
        private void Initialize()
        {
            WorkMonth = DateTime.Today;
            SelectedDays = new Dictionary<DateTime, SelectDayElemet>();
            this.PropertyChanged += OnPropertyChanged;
        }
        public DateTime DisplayDateStart
        {
            get { return GetFirstDay(); }
            set { }
        }
        public DateTime DisplayDateEnd
        {
            get { return GetLastDay(); }
            set { }
        }
        DateTime _p_DisplayDate;
        public DateTime WorkMonth
        {
            get { return _p_DisplayDate; }
            set
            {
                _p_DisplayDate = value;
                OnPropertyChanged(() => p_DisplayDate);
                OnPropertyChanged(() => DisplayDate);
                OnPropertyChanged(() => DisplayDateStart);
                OnPropertyChanged(() => DisplayDateEnd);
            }
        }    
        private void OnPropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
        {
            // Ignore properties other than DisplayDate
            if (e.PropertyName != "DisplayDate") return;
            // Ignore change if date is DateTime.MinValue
            if (DisplayDate == DateTime.MinValue) return;
            // Ignore change if month is the same
            if (DisplayDate.IsSameMonthAs(m_OldDisplayDate)) return;

            // Update OldDisplayDate
            m_OldDisplayDate = p_DisplayDate;
        }
        #region Administrative Properties
        public virtual bool IgnorePropertyChangeEvents { get; set; }    
        #endregion
    }
}

класс элемента унаследован от BaseModel в которой реализованы интерфейсы

INotifyPropertyChanging, INotifyPropertyChanged

public class SelectDayElemet: BaseModel
 {
    public SelectDayElemet()
     {
         //Date = new DateTime();
         Background = new LinearGradientBrush(
             new GradientStopCollection()
                 {
                  new GradientStop((Color)ColorConverter.ConvertFromString("#FFE4EAF0"),0),
                  new GradientStop((Color)ColorConverter.ConvertFromString("#FFECF0F4"),0.16),
                  new GradientStop((Color)ColorConverter.ConvertFromString("#FFFCFCFD"),0.16),
                  new GradientStop((Color)ColorConverter.ConvertFromString("#FFFFFFFF"),1),
                 });
         NumForeground = new SolidColorBrush(Colors.Black);
         //  DayForeground = new SolidColorBrush(Colors.Black);
     }
   //  , Brush __DayForeground
     public SelectDayElemet(int __num, Brush __Background, Brush __NumForeground)
     {
         _NUM          = __num;
         Background    = __Background;
         NumForeground = __NumForeground;
         //   DayForeground = __DayForeground;
     }
     //, string __StrDayForeground
     public SelectDayElemet(int __num, string __StrBackground, string __StrForeground)
     {
         _NUM = __num;
         Background    = new SolidColorBrush((Color)ColorConverter.ConvertFromString(__StrBackground));
         NumForeground = new SolidColorBrush((Color)ColorConverter.ConvertFromString(__StrForeground));
        // DayForeground = new SolidColorBrush((Color)ColorConverter.ConvertFromString(__StrDayForeground));
     }
     int _NUM;
    public int NUM
     {
         get { return _NUM; }
         set {
               _NUM = value;
               OnPropertyChanged(()=>NUM);
             }
     }
     Brush _Background;
    public Brush Background
     {
         get { return _Background; }
         set {
               _Background = value;
               OnPropertyChanged(()=>Background);
             }
     }
     Brush _NumForeground;
    public Brush NumForeground
     {
         get { return _NumForeground; }
         set {
               _NumForeground = value;
               OnPropertyChanged(()=>NumForeground);
             }
     }

BindingProxy классная штука откуда стянул привожу

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
namespace MonthCalendar.Helpers
{
    /**
     * @brief Прокси класс для доступа к данным 
     * взято с https://social.technet.microsoft.com/wiki/contents/articles/31422.wpf-passing-a-data-bound-value-to-a-validation-rule.aspx
     * 
     */
    public class BindingProxy : System.Windows.Freezable
    {
        /**
         * @brief Согласно требованиям "необходимо переопределить подкласс CreateInstanceCore метод" переопределяем
         */
        protected override Freezable CreateInstanceCore()
        {
            return new BindingProxy();
        }
        /**
         * @brief объект данных который будем "биндить"
         */
        public object Data
        {
            get { return (object)GetValue(DataProperty); }
            set { SetValue(DataProperty, value); }
        }
        /**
         * @brief Создаем DependencyProperty с именем "Data"
         */
        public static readonly DependencyProperty DataProperty =
            DependencyProperty.Register("Data", typeof(object), typeof(BindingProxy), new PropertyMetadata(null));
    }
}

конвенторы я не смог придумать лучшего способа чем мультибиндинг

using MonthCalendar.Helpers;
using MonthCalendar.Model;
using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Data;
namespace MonthCalendar.Converters
{
    public class NumberDateConverter : IMultiValueConverter
    {
        public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
        {
            try
            {
                if ((values[0] == null) || (values[1] == null)) return DependencyProperty.UnsetValue;
                if ((values[0] == DependencyProperty.UnsetValue) || (values[1] == DependencyProperty.UnsetValue)) return DependencyProperty.UnsetValue;
                var targetDate = (DateTime)values[0];
                var SelectedDays = (Dictionary<DateTime, SelectDayElemet>)values[1];
                try
                {
                  SelectDayElemet val = null;
                  var res = SelectedDays.TryGetValue(targetDate, out val);
                  if (res)
                  return val.NUM.ToString();//parent.SelectedDays[targetDate].ToString();
                  else
                        return DependencyProperty.UnsetValue;
                }
                catch (Exception ex)
                {
                    return DependencyProperty.UnsetValue;
                }
            }
            catch (Exception ex)
            {
                return DependencyProperty.UnsetValue;
            }
        }
        public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
        {
            throw new NotImplementedException();
        }
    }   
}