.net - 添加 "Today Button"到日历控件

Question

我的 WPF MVVM 应用程序中有以下样式。

<Style x:Key="DefaultCalendar" TargetType="Calendar">
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type Calendar}">
                <StackPanel HorizontalAlignment="Center" Name="PART_Root">
                    <CalendarItem Background="{TemplateBinding Control.Background}" BorderBrush="{TemplateBinding Control.BorderBrush}" BorderThickness="{TemplateBinding Control.BorderThickness}" Name="PART_CalendarItem" Style="{TemplateBinding Calendar.CalendarItemStyle}" />
                    <Button Content="Today" Command="Commands:CalendarCommands.SelectToday" CommandParameter="{Binding RelativeSource={RelativeSource Mode=TemplatedParent}}"/>
                </StackPanel>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

我创建了命令类

namespace Viterra.Freight.Client.Resources.Commands
{
    public class CalendarCommands
    {
        public static RoutedCommand SelectToday = new RoutedCommand("Today", typeof(CalendarCommands));
    }
}

它会在日历打开时显示，但是该按钮被禁用。我确定我需要使用此路由命令做更多事情以便它设置日期，但我不确定是什么或在哪里。

编辑:最终解决方案请注意，我还一直在修改 DatePicker 以使用此日历样式。

<Style x:Key="DefaultCalendar" TargetType="Calendar">
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type Calendar}">
                <StackPanel HorizontalAlignment="Center" Name="PART_Root">
                    <CalendarItem Background="{TemplateBinding Control.Background}" BorderBrush="{TemplateBinding Control.BorderBrush}" BorderThickness="{TemplateBinding Control.BorderThickness}" Name="PART_CalendarItem" Style="{TemplateBinding Calendar.CalendarItemStyle}" />
                    <Button Content="Today" Command="Commands:CalendarCommands.SelectToday" CommandParameter="{Binding RelativeSource={RelativeSource Mode=TemplatedParent}}" />
                </StackPanel>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

<!-- style for default datepicker -->
<Style x:Key="DefaultDatePicker" TargetType="DatePicker">
    <Setter Property="Height" Value="23"/>
    <Setter Property="VerticalAlignment" Value="Center"/>
    <Setter Property="CalendarStyle" Value="{StaticResource DefaultCalendar}" />
    <Setter Property="Validation.ErrorTemplate" Value="{StaticResource DateTimeValidationTemplate}" />
    <Style.Triggers>
        <Trigger Property="Validation.HasError" Value="true">
            <Setter Property="ToolTip" Value="{Binding RelativeSource={x:Static RelativeSource.Self}, Path=(Validation.Errors).CurrentItem.ErrorContent}"/>
        </Trigger>
    </Style.Triggers>
</Style>

和 CalendarCommands.cs

using System;
using System.Windows.Input;
using System.Windows.Controls;

namespace Viterra.Freight.Client.Resources.Commands
{
    public static class CalendarCommands
    {
        private static readonly SelectTodayCommand _selectTodayCommand = new SelectTodayCommand();

        public static ICommand SelectToday
        {
            get { return _selectTodayCommand; }
        }

        private sealed class SelectTodayCommand : ICommand
        {
            public event EventHandler CanExecuteChanged
            {
                add { CommandManager.RequerySuggested += value; }
                remove { CommandManager.RequerySuggested -= value; }
            }

            public bool CanExecute(object parameter)
            {
                return parameter is Calendar;
            }

            public void Execute(object parameter)
            {
                var calendar = parameter as Calendar;
                if (calendar == null) 
                    return;

                var today = DateTime.Today;
                calendar.SelectedDate = today;
                calendar.DisplayDate = today;
            }
        }
    }
}

Answer 1

或者，如果您不想使用代码隐藏和 CommandBindings，您可以使用简单的 ICommand 实现:

public static class CalendarCommands
{
   private static readonly SelectTodayCommand _selectToday = new SelectTodayCommand();

   public static ICommand SelectToday
   {
      get { return _selectToday; }
   }

   private sealed class SelectTodayCommand : ICommand
   {
      public event EventHandler CanExecuteChanged
      {
         add { CommandManager.RequerySuggested += value; }
         remove { CommandManager.RequerySuggested -= value; }
      }

      public bool CanExecute(object parameter)
      {
         return parameter is Calendar;
      }

      public void Execute(object parameter)
      {
         var calendar = parameter as Calendar;
         if (calendar != null)
         {
            DateTime today = DateTime.Today;
            calendar.SelectedDate = today;
            calendar.DisplayDate = today;
         }
      }
   }
}