一．前言
申明：WPF自定义控件与样式是一个系列文章，前后是有些关联的，但大多是按照由简到繁的顺序逐步发布的等，若有不明白的地方可以参考本系列前面的文章，文末附有部分文章链接。
本文主要内容：
- 日历控件Calendar自定义样式；
- 日期控件DatePicker自定义样式，及Label标签、水印、清除日期功能扩展；
二．Calendar自定义样式
先看看效果：
从上面图可以看出，日历的显示其实有三种状态，如下面的分解图：
- "日"部分的显示；
- "月"部分的显示；
- "年"部分的显示；
因此一个完整的日历，就包含多个部分，首先是"日"按钮的样式：
<!--Day按钮样式-->
<Style x:Key="CalendarDayButtonStyle" TargetType="{x:Type CalendarDayButton}">
<Setter Property="MinWidth" Value="28" />
<Setter Property="MinHeight" Value="5" />
<Setter Property="FontFamily" Value="{StaticResource FontFamily}" />
<Setter Property="HorizontalContentAlignment" Value="Center" />
<Setter Property="VerticalContentAlignment" Value="Center" />
<Setter Property="Background" Value="Transparent" />
<Setter Property="Foreground" Value="{StaticResource TextForeground}" />
<Setter Property="Margin" Value="0" />
<Setter Property="IsTabStop" Value="False" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type CalendarDayButton}">
<Grid x:Name="Grid" Margin="{TemplateBinding Margin}">
<Border x:Name="Bg" Background="{TemplateBinding Background}" />
<ContentPresenter x:Name="NormalText" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
Margin="5,2,5,2" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
TextElement.Foreground="{TemplateBinding Foreground}" />
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="IsSelected" Value="True">
<Setter Property="Background" Value="{StaticResource ItemSelectedBackground}"></Setter>
<Setter Property="Foreground" Value="{StaticResource ItemSelectedForeground}"></Setter>
</Trigger>
<Trigger Property="IsToday" Value="True">
<Setter Property="Background" Value="{StaticResource ItemHighlighteBackground}"></Setter>
<Setter Property="Foreground" Value="{StaticResource ItemHighlighteForeground}"></Setter>
</Trigger>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Background" Value="{StaticResource ItemMouseOverBackground}"></Setter>
<Setter Property="Foreground" Value="{StaticResource ItemMouseOverForeground}"></Setter>
</Trigger>
<!--不可用日期-->
<Trigger Property="IsBlackedOut" Value="True">
<Setter Property="Opacity" Value="{StaticResource DisableOpacity}" TargetName="Grid"></Setter>
</Trigger>
<!--不在当月的日期-->
<Trigger Property="IsInactive" Value="True">
<Setter Property="Opacity" Value="0.65" TargetName="Grid"></Setter>
</Trigger>
<Trigger Property="IsEnabled" Value="False">
<Setter Property="Opacity" Value="{StaticResource DisableOpacity}" TargetName="Grid"></Setter>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
日历日期面板样式：
<!--日历日期面板样式-->
<Style x:Key="CalendarItemStyle" TargetType="{x:Type CalendarItem}">
<Setter Property="Margin" Value="0,1,0,1" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type CalendarItem}">
<ControlTemplate.Resources>
<!-- 头部星期样式-->
<DataTemplate x:Key="{x:Static CalendarItem.DayTitleTemplateResourceKey}">
<TextBlock Text="{Binding}" FontWeight="Bold" FontFamily="{StaticResource FontFamily}" Foreground="{StaticResource PressedForeground}"
FontSize="{StaticResource HeaderFontSize}" HorizontalAlignment="Center" VerticalAlignment="Center" Margin="0,6,0,6" Opacity="0.8" />
</DataTemplate>
</ControlTemplate.Resources>
<Grid x:Name="PART_Root">
<Border BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="1" Background="{TemplateBinding Background}" Margin="{TemplateBinding Margin}">
<Grid Margin="2">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<!--Header-->
<Grid Grid.Row="0" HorizontalAlignment="Stretch" Background="{StaticResource HeaderBackground}">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="2*"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<local:FButton x:Name="PART_HeaderButton" FontWeight="Bold" Style="{StaticResource FButton_Transparency}"
Focusable="False" Grid.Column="1" FIcon="{x:Null}"/>
<local:FButton x:Name="PART_PreviousButton" Style="{StaticResource FButton_Transparency}"
Focusable="False" Grid.Column="0" FIconSize="18" Content="" FIcon=""/>
<local:FButton x:Name="PART_NextButton" Style="{StaticResource FButton_Transparency}"
Focusable="False" Grid.Column="2" FIconSize="18" Content="" FIcon=""/>
</Grid>
<!--PART_MonthView-->
<Grid x:Name="PART_MonthView" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Margin="6,1,6,6" Grid.Row="1" Visibility="Visible">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="*" />
<ColumnDefinition Width="*" />
<ColumnDefinition Width="*" />
<ColumnDefinition Width="*" />
<ColumnDefinition Width="*" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="*" />
<RowDefinition Height="*" />
<RowDefinition Height="*" />
<RowDefinition Height="*" />
<RowDefinition Height="*" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
</Grid>
<!--PART_YearView-->
<Grid x:Name="PART_YearView" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Margin="6,10,6,10" Grid.Row="1" Visibility="Hidden">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="*" />
<ColumnDefinition Width="*" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="*" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
</Grid>
</Grid>
</Border>
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="IsEnabled" Value="False">
<Setter Property="Opacity" TargetName="PART_Root" Value="{StaticResource DisableOpacity}" />
</Trigger>
<DataTrigger Binding="{Binding DisplayMode, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Calendar}}}" Value="Year">
<Setter Property="Visibility" TargetName="PART_MonthView" Value="Hidden" />
<Setter Property="Visibility" TargetName="PART_YearView" Value="Visible" />
</DataTrigger>
<!--Decade 美 ['dɛked] n. 十年，十年期；十-->
<DataTrigger Binding="{Binding DisplayMode, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Calendar}}}" Value="Decade">
<Setter Property="Visibility" TargetName="PART_MonthView" Value="Hidden" />
<Setter Property="Visibility" TargetName="PART_YearView" Value="Visible" />
</DataTrigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
年月按钮样式：
<!--年、月按钮样式-->
<Style x:Key="CalendarButtonStyle" TargetType="{x:Type CalendarButton}">
<Setter Property="Background" Value="Transparent" />
<Setter Property="MinWidth" Value="40" />
<Setter Property="MinHeight" Value="42" />
<Setter Property="FontSize" Value="{StaticResource FontSize}" />
<Setter Property="FontFamily" Value="{StaticResource FontFamily}" />
<Setter Property="HorizontalContentAlignment" Value="Center" />
<Setter Property="VerticalContentAlignment" Value="Center" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type CalendarButton}">
<Grid x:Name="Grid" Margin="{TemplateBinding Margin}">
<Border x:Name="Bg" Background="{TemplateBinding Background}" />
<ContentPresenter x:Name="NormalText" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
Margin="5,2,5,2" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
TextElement.Foreground="{TemplateBinding Foreground}" />
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="IsFocused" Value="True">
<Setter Property="Background" Value="{StaticResource ItemSelectedBackground}"></Setter>
<Setter Property="Foreground" Value="{StaticResource ItemSelectedForeground}"></Setter>
</Trigger>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Background" Value="{StaticResource ItemMouseOverBackground}"></Setter>
<Setter Property="Foreground" Value="{StaticResource ItemMouseOverForeground}"></Setter>
</Trigger>
<!--不在当月的日期-->
<Trigger Property="IsInactive" Value="True">
<Setter Property="Opacity" Value="0.8" TargetName="Grid"></Setter>
</Trigger>
<Trigger Property="IsEnabled" Value="False">
<Setter Property="Opacity" Value="{StaticResource DisableOpacity}" TargetName="Grid"></Setter>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
最后综合以上的样式，定义我们需要的Calendar样式就差一步之遥了。
<!--默认日历样式-->
<Style x:Key="DefaultCalendar" TargetType="{x:Type Calendar}">
<Setter Property="SnapsToDevicePixels" Value="True" />
<Setter Property="Foreground" Value="{StaticResource TextForeground}" />
<Setter Property="CalendarDayButtonStyle" Value="{StaticResource CalendarDayButtonStyle}" />
<Setter Property="CalendarItemStyle" Value="{StaticResource CalendarItemStyle}" />
<Setter Property="CalendarButtonStyle" Value="{StaticResource CalendarButtonStyle}" />
<Setter Property="Background" Value="{StaticResource PopupBackground}" />
<Setter Property="BorderBrush" Value="{StaticResource ControlBorderBrush}" />
<Setter Property="BorderThickness" Value="1" />
<Setter Property="FontSize" Value="13" />
<Setter Property="FontFamily" Value="{StaticResource FontFamily}" />
<Setter Property="IsTodayHighlighted" Value="True" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type Calendar}">
<StackPanel x:Name="PART_Root" HorizontalAlignment="Center" Background="Transparent">
<CalendarItem x:Name="PART_CalendarItem" BorderBrush="{TemplateBinding BorderBrush}" FontSize="{TemplateBinding FontSize}"
FontFamily="{TemplateBinding FontFamily}"
BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}"
Style="{TemplateBinding CalendarItemStyle}" />
</StackPanel>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
三．DatePicker自定义样式，及Label标签、水印、清除日期功能扩展
有了上面的日历样式，下面做DatePicker的样式就好办了，其实就是TextBox+Button+Calendar。此处的实现同上一篇（WPF自定义控件与样式(3)-TextBox & RichTextBox & PasswordBox样式）思路基本一致，因此本文就不做更多的解释，可以参考本系列前面的文章（末尾附录有链接）先看看效果图：
3.1 DatePicker自定义样式
基本样式定义：
<Style x:Key="DefaultDatePicker" TargetType="{x:Type DatePicker}">
<Setter Property="Foreground" Value="{StaticResource TextForeground}" />
<Setter Property="Background" Value="{StaticResource TextBackground}" />
<Setter Property="BorderThickness" Value="1" />
<Setter Property="BorderBrush" Value="{StaticResource ControlBorderBrush}" />
<Setter Property="local:ControlAttachProperty.FocusBorderBrush" Value="{StaticResource FocusBorderBrush}" />
<Setter Property="local:ControlAttachProperty.MouseOverBorderBrush" Value="{StaticResource MouseOverBorderBrush}" />
<Setter Property="local:ControlAttachProperty.FIconSize" Value="21" />
<Setter Property="FontFamily" Value="{StaticResource FontFamily}" />
<Setter Property="FontSize" Value="{StaticResource FontSize}" />
<Setter Property="MinHeight" Value="26" />
<Setter Property="Height" Value="30" />
<Setter Property="Width" Value="200" />
<Setter Property="HorizontalContentAlignment" Value="Stretch" />
<Setter Property="IsTodayHighlighted" Value="True" />
<Setter Property="Padding" Value="0" />
<Setter Property="Margin" Value="0" />
<Setter Property="SelectedDate" Value="{x:Null}" />
<Setter Property="SnapsToDevicePixels" Value="True" />
<Setter Property="CalendarStyle" Value="{StaticResource DefaultCalendar}" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type DatePicker}">
<Grid x:Name="PART_Root">
<Border x:Name="Bg" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"
BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}"
Background="{TemplateBinding Background}" />
<Grid x:Name="PART_InnerGrid" Margin="0">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="*" />
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<!--Label区域-->
<ContentControl x:Name="Label" Template="{TemplateBinding local:ControlAttachProperty.LabelTemplate}" IsTabStop="False" IsHitTestVisible="False"
Content="{TemplateBinding local:ControlAttachProperty.Label}" Margin="1,1,0,1"/>
<!--附加内容区域-->
<Border x:Name="PART_AttachContent" Grid.Column="2" VerticalAlignment="Center" HorizontalAlignment="Center" >
<ContentControl VerticalAlignment="Center" VerticalContentAlignment="Center" Template="{TemplateBinding local:ControlAttachProperty.AttachContent}"/>
</Border>
<!--下拉按钮-->
<ToggleButton x:Name="PART_DropDownToggle" IsTabStop="False" Style="{StaticResource FIconToggleButton}"
IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Margin="1,1,3,1"
Grid.Column="3" local:ControlAttachProperty.FIconSize="{TemplateBinding local:ControlAttachProperty.FIconSize}"
Background="{TemplateBinding local:ControlAttachProperty.FocusBackground}"/>
<!--水印-->
<Border Grid.Column="1">
<TextBlock x:Name="Message" Padding="0" Visibility="Collapsed" Text="{TemplateBinding local:ControlAttachProperty.Watermark}"
Foreground="{TemplateBinding Foreground}" IsHitTestVisible="False" Opacity="{StaticResource WatermarkOpacity}" HorizontalAlignment="Left" TextAlignment="Center"
VerticalAlignment="Center" Margin="5,2,5,2" />
</Border>
<!--Date内容区-->
<Grid Grid.Column="1">
<TextBox x:Name="PART_TextBox" Style="{StaticResource EditableTextBoxStyle}" HorizontalAlignment="Stretch"
SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" IsHitTestVisible="True" IsReadOnly="True"
FontFamily="{TemplateBinding FontFamily}" Foreground="{TemplateBinding Foreground}" FontSize="{TemplateBinding FontSize}"
Text="{Binding Path=SelectedDate,Mode=OneWay,RelativeSource={RelativeSource TemplatedParent},StringFormat={StaticResource DateFormat}}"/>
</Grid>
<!--弹出日历-->
<Popup x:Name="PART_Popup" AllowsTransparency="True" Placement="Bottom"
PlacementTarget="{Binding ElementName=PART_Root}" StaysOpen="False" />
</Grid>
</Grid>
<ControlTemplate.Triggers>
<!--1.显示水印-->
<DataTrigger Binding="{Binding RelativeSource={RelativeSource Self}, Path=Text}" Value="">
<Setter TargetName="Message" Property="Visibility" Value="Visible" />
</DataTrigger>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="BorderBrush" Value="{Binding Path=(local:ControlAttachProperty.MouseOverBorderBrush),RelativeSource={RelativeSource Self}}"/>
</Trigger>
<Trigger Property="IsFocused" Value="True">
<Setter Property="BorderBrush" Value="{Binding Path=(local:ControlAttachProperty.FocusBorderBrush),RelativeSource={RelativeSource Self}}"/>
</Trigger>
<Trigger Property="IsKeyboardFocusWithin" Value="True">
<Setter Property="BorderBrush" Value="{Binding Path=(local:ControlAttachProperty.FocusBorderBrush),RelativeSource={RelativeSource Self}}"/>
</Trigger>
<Trigger Property="IsEnabled" Value="False">
<Setter TargetName="PART_Root" Property="Opacity" Value="{StaticResource DisableOpacity}" />
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
水印效果：
使用示例：
<DatePicker Margin="3" core:ControlAttachProperty.Watermark="妈的快输入日期"/>
<DatePicker Margin="3" SelectedDate="{x:Static system:DateTime.Today}"/>
<DatePicker Margin="3" IsEnabled="False" SelectedDate="{x:Static system:DateTime.Today}"/>
3.2 Label标签
通过扩展基础样式中的标签附加属性实现，定义样式代码：
<!--DatePicker包含附加属性Label的样式 LabelDatePicker -->
<Style TargetType="{x:Type DatePicker}" x:Key="LabelDatePicker" BasedOn="{StaticResource DefaultDatePicker}">
<Setter Property="Width" Value="260"></Setter>
<Setter Property="local:ControlAttachProperty.LabelTemplate" >
<Setter.Value>
<ControlTemplate TargetType="ContentControl">
<Border Width="60" Background="{StaticResource TextLabelBackground}">
<TextBlock VerticalAlignment="Center" HorizontalAlignment="Right" Margin="2" Text="{TemplateBinding Content}"></TextBlock>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
效果图：
使用示例：
<DatePicker Margin="3" Style="{StaticResource LabelClearButtonDatePicker}" core:ControlAttachProperty.Watermark="选择出生日期" core:ControlAttachProperty.Label="出生日期"/>
<DatePicker Margin="3" Style="{StaticResource LabelDatePicker}" core:ControlAttachProperty.Label="死亡日期" SelectedDate="{x:Static system:DateTime.Today}"/>
<DatePicker Margin="3" Style="{StaticResource LabelDatePicker}" core:ControlAttachProperty.Label="非法日期" IsEnabled="False" SelectedDate="{x:Static system:DateTime.Today}"/>
3.3 清除日期值的功能扩展
此功能在前面的文章有介绍过（参考本文末尾链接），效果在上面的图片中可以看到。样式代码：
<!--DatePicker包含清除Text按钮的样式 ClearButtonDatePicker -->
<Style TargetType="{x:Type DatePicker}" x:Key="ClearButtonDatePicker" BasedOn="{StaticResource DefaultDatePicker}">
<Setter Property="local:ControlAttachProperty.AttachContent">
<Setter.Value>
<ControlTemplate>
<local:FButton FIcon="" Style="{StaticResource FButton_Transparency}" IsTabStop="False" FIconMargin="0"
local:ControlAttachProperty.IsClearTextButtonBehaviorEnabled="True" Command="local:ControlAttachProperty.ClearTextCommand"
CommandParameter="{Binding RelativeSource={RelativeSource FindAncestor,AncestorType={x:Type DatePicker}}}"
Margin="1,3,0,4" FIconSize="14" Foreground="{StaticResource TextForeground}" Cursor="Arrow"/>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style> <!--DatePicker包含附加属性Label，以及ClearText按钮的样式 LabelClearButtonDatePicker -->
<Style TargetType="{x:Type DatePicker}" x:Key="LabelClearButtonDatePicker" BasedOn="{StaticResource DefaultDatePicker}">
<Setter Property="Width" Value="280"></Setter>
<Setter Property="local:ControlAttachProperty.LabelTemplate" >
<Setter.Value>
<ControlTemplate TargetType="ContentControl">
<Border Width="60" Background="{StaticResource TextLabelBackground}">
<TextBlock VerticalAlignment="Center" HorizontalAlignment="Right" Margin="2" Text="{TemplateBinding Content}"></TextBlock>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
<Setter Property="local:ControlAttachProperty.AttachContent">
<Setter.Value>
<ControlTemplate>
<local:FButton FIcon="" Style="{StaticResource FButton_Transparency}" IsTabStop="False" FIconMargin="0"
local:ControlAttachProperty.IsClearTextButtonBehaviorEnabled="True" Command="local:ControlAttachProperty.ClearTextCommand"
CommandParameter="{Binding RelativeSource={RelativeSource FindAncestor,AncestorType={x:Type DatePicker}}}"
Margin="0,3,0,4" FIconSize="14" Foreground="{StaticResource TextForeground}" Cursor="Arrow"/>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
使用示例：
<DatePicker Margin="3" Style="{StaticResource ClearButtonDatePicker}"/>
<DatePicker Margin="3" Style="{StaticResource LabelClearButtonDatePicker}" core:ControlAttachProperty.Watermark="选择出生日期" core:ControlAttachProperty.Label="出生日期"/>
附录：参考引用
WPF自定义控件与样式(1)-矢量字体图标(iconfont)
WPF自定义控件与样式(3)-TextBox & RichTextBox & PasswordBox样式、水印、Label标签、功能扩展
WPF自定义控件与样式(4)-CheckBox/RadioButton自定义样式
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