我有一个WPF应用程序。我有一个名为Metro.xaml的资源字典。我在这个资源字典中添加了一些样式。在我为Calendar及其部件添加控件模板之前，它工作正常。
这是名为Metro.xaml的ResourceDictionary：
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:c="clr-namespace:DairyManagement.Converters"
xmlns:powerMask="clr-namespace:DairyManagement.PowerControls.MaskedTextbox">
<Style TargetType="{x:Type FrameworkElement}" x:Key="baseStyle">
<Setter Property="TextElement.FontSize" Value="30" />
<Setter Property="TextElement.FontFamily" Value="Nilkanth" />
</Style>
<!--Calendar-->
<Style TargetType="Calendar">
<Setter Property="IsTabStop" Value="False" />
<Setter Property="Background">
<Setter.Value>
<LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
<GradientStop Color="#FFD3DEE8" Offset="0" />
<GradientStop Color="#FFD3DEE8" Offset="0.16" />
<GradientStop Color="#FFFCFCFD" Offset="0.16" />
<GradientStop Color="#FFFFFFFF" Offset="1" />
</LinearGradientBrush>
</Setter.Value>
</Setter>
<Setter Property="BorderThickness" Value="1" />
<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="Template">
<Setter.Value>
<ControlTemplate TargetType="Calendar">
<StackPanel x:Name="Root" HorizontalAlignment="Center">
<CalendarItem x:Name="CalendarItem" Background="{TemplateBinding Background}"
BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" />
</StackPanel>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<Style TargetType="CalendarItem">
<!-- eliminated-->
</Style>
<Style TargetType="CalendarDayButton">
<Setter Property="Background" Value="#FFBADDE9" />
<Setter Property="FontSize" Value="10" />
<Setter Property="HorizontalContentAlignment" Value="Center" />
<Setter Property="VerticalContentAlignment" Value="Center" />
<Setter Property="MinWidth" Value="5" />
<Setter Property="MinHeight" Value="5" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="CalendarDayButton">
<Grid>
<VisualStateManager.VisualStateGroups>
<VisualStateGroup x:Name="CommonStates">
<VisualStateGroup.Transitions>
<VisualTransition GeneratedDuration="0:0:0.1" />
</VisualStateGroup.Transitions>
<VisualState x:Name="Normal" />
<VisualState x:Name="MouseOver">
<Storyboard>
<DoubleAnimation Storyboard.TargetName="Background" Storyboard.TargetProperty="Opacity" To=".5"
Duration="0" />
</Storyboard>
</VisualState>
<VisualState x:Name="Pressed">
<Storyboard>
<DoubleAnimation Storyboard.TargetName="Background" Storyboard.TargetProperty="Opacity" To=".5"
Duration="0" />
</Storyboard>
</VisualState>
<VisualState x:Name="Disabled">
<Storyboard>
<DoubleAnimation Storyboard.TargetName="Background" Storyboard.TargetProperty="Opacity" To="0"
Duration="0" />
<DoubleAnimation Storyboard.TargetName="Content" Storyboard.TargetProperty="Opacity" To=".35"
Duration="0" />
</Storyboard>
</VisualState>
</VisualStateGroup>
<VisualStateGroup x:Name="SelectionStates">
<VisualStateGroup.Transitions>
<VisualTransition GeneratedDuration="0" />
</VisualStateGroup.Transitions>
<VisualState x:Name="Unselected" />
<VisualState x:Name="Selected">
<Storyboard>
<DoubleAnimation Storyboard.TargetName="SelectedBackground" Storyboard.TargetProperty="Opacity" To=".75"
Duration="0" />
</Storyboard>
</VisualState>
</VisualStateGroup>
<VisualStateGroup x:Name="CalendarButtonFocusStates">
<VisualStateGroup.Transitions>
<VisualTransition GeneratedDuration="0" />
</VisualStateGroup.Transitions>
<VisualState x:Name="CalendarButtonFocused">
<Storyboard>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="FocusVisual"
Storyboard.TargetProperty="Visibility" Duration="0">
<DiscreteObjectKeyFrame KeyTime="0" Value="Visible" />
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
<VisualState x:Name="CalendarButtonUnfocused">
<Storyboard>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="FocusVisual"
Storyboard.TargetProperty="Visibility" Duration="0">
<DiscreteObjectKeyFrame KeyTime="0" Value="Collapsed" />
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
</VisualStateGroup>
<VisualStateGroup x:Name="ActiveStates">
<VisualStateGroup.Transitions>
<VisualTransition GeneratedDuration="0" />
</VisualStateGroup.Transitions>
<VisualState x:Name="Active" />
<VisualState x:Name="Inactive">
<Storyboard>
<ColorAnimation Storyboard.TargetName="Content"
Storyboard.TargetProperty="(ContentControl.Foreground).(GradientBrush.GradientStops)[2].(GradientStop.Color)"
To="#FF777777" Duration="0" />
<ColorAnimation Storyboard.TargetName="Content"
Storyboard.TargetProperty="(ContentControl.Foreground).(GradientBrush.GradientStops)[3].(GradientStop.Color)"
To="#FF777777" Duration="0" />
</Storyboard>
</VisualState>
</VisualStateGroup>
<VisualStateGroup x:Name="DayStates">
<VisualStateGroup.Transitions>
<VisualTransition GeneratedDuration="0" />
</VisualStateGroup.Transitions>
<VisualState x:Name="RegularDay" />
<VisualState x:Name="Today">
<Storyboard>
<DoubleAnimation Storyboard.TargetName="TodayBackground" Storyboard.TargetProperty="Opacity" To="1"
Duration="0" />
<DoubleAnimation Storyboard.TargetName="Content"
Storyboard.TargetProperty="(ContentControl.Foreground).(GradientBrush.GradientStops)[1].(GradientStop.Offset)"
To="1" Duration="0" />
<DoubleAnimation Storyboard.TargetName="Content"
Storyboard.TargetProperty="(ContentControl.Foreground).(GradientBrush.GradientStops)[2].(GradientStop.Offset)"
To="1" Duration="0" />
</Storyboard>
</VisualState>
</VisualStateGroup>
<VisualStateGroup x:Name="BlackoutDayStates">
<VisualStateGroup.Transitions>
<VisualTransition GeneratedDuration="0" />
</VisualStateGroup.Transitions>
<VisualState x:Name="NormalDay" />
<VisualState x:Name="BlackoutDay">
<Storyboard>
<DoubleAnimation Storyboard.TargetName="BlackoutVisual" Storyboard.TargetProperty="Opacity" To=".2"
Duration="0" />
</Storyboard>
</VisualState>
</VisualStateGroup>
</VisualStateManager.VisualStateGroups>
<Rectangle x:Name="TodayBackground" RadiusX="1" RadiusY="1" Opacity="0" Fill="#FFAAAAAA" />
<Rectangle x:Name="SelectedBackground" RadiusX="1" RadiusY="1" Opacity="0" Fill="{TemplateBinding Background}" />
<Rectangle x:Name="Background" RadiusX="1" RadiusY="1" Opacity="0" Fill="{TemplateBinding Background}" />
<ContentControl x:Name="Content" IsTabStop="False" Content="{TemplateBinding Content}"
ContentTemplate="{TemplateBinding ContentTemplate}"
HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
FontSize="{TemplateBinding FontSize}" Margin="5,1,5,1">
<ContentControl.Foreground>
<LinearGradientBrush>
<GradientStop Offset="0" Color="#FFFFFFFF" />
<GradientStop Offset="0" Color="#FFFFFFFF" />
<GradientStop Offset="0" Color="#FF333333" />
<GradientStop Offset="1" Color="#FF333333" />
</LinearGradientBrush>
</ContentControl.Foreground>
</ContentControl>
<Path x:Name="BlackoutVisual" Opacity="0" Margin="3" HorizontalAlignment="Stretch" VerticalAlignment="Stretch"
RenderTransformOrigin="0.5,0.5" Fill="#FF000000" Stretch="Fill"
Data="M8.1772461,11.029181 L10.433105,11.029181 L11.700684,12.801641 L12.973633,11.029181 L15.191895,11.029181 L12.844727,13.999395 L15.21875,17.060919 L12.962891,17.060919 L11.673828,15.256231 L10.352539,17.060919 L8.1396484,17.060919 L10.519043,14.042364 z" />
<Rectangle x:Name="FocusVisual" Visibility="Collapsed" IsHitTestVisible="false" RadiusX="1" RadiusY="1" Stroke="#FF6DBDD1" />
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<Style TargetType="CalendarButton">
<Setter Property="Background" Value="#FFBADDE9" />
<Setter Property="FontSize" Value="10" />
<Setter Property="HorizontalContentAlignment" Value="Center" />
<Setter Property="VerticalContentAlignment" Value="Center" />
<Setter Property="MinWidth" Value="40" />
<Setter Property="MinHeight" Value="42" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="CalendarButton">
<Grid>
<VisualStateManager.VisualStateGroups>
<VisualStateGroup x:Name="CommonStates">
<VisualStateGroup.Transitions>
<VisualTransition GeneratedDuration="0:0:0.1" />
</VisualStateGroup.Transitions>
<VisualState x:Name="Normal" />
<VisualState x:Name="MouseOver">
<Storyboard>
<DoubleAnimation Storyboard.TargetName="Background" Storyboard.TargetProperty="Opacity"
To=".5" Duration="0" />
</Storyboard>
</VisualState>
<VisualState x:Name="Pressed">
<Storyboard>
<DoubleAnimation Storyboard.TargetName="Background" Storyboard.TargetProperty="Opacity" To=".5"
Duration="0" />
</Storyboard>
</VisualState>
</VisualStateGroup>
<VisualStateGroup x:Name="SelectionStates">
<VisualStateGroup.Transitions>
<VisualTransition GeneratedDuration="0" />
</VisualStateGroup.Transitions>
<VisualState x:Name="Unselected" />
<VisualState x:Name="Selected">
<Storyboard>
<DoubleAnimation Storyboard.TargetName="SelectedBackground" Storyboard.TargetProperty="Opacity" To=".75"
Duration="0" />
</Storyboard>
</VisualState>
</VisualStateGroup>
<VisualStateGroup x:Name="ActiveStates">
<VisualStateGroup.Transitions>
<VisualTransition GeneratedDuration="0" />
</VisualStateGroup.Transitions>
<VisualState x:Name="Active" />
<VisualState x:Name="Inactive">
<Storyboard>
<ColorAnimation Storyboard.TargetName="Content"
Storyboard.TargetProperty="(ContentControl.Foreground).(SolidColorBrush.Color)"
To="#FF777777" Duration="0" />
</Storyboard>
</VisualState>
</VisualStateGroup>
<VisualStateGroup x:Name="CalendarButtonFocusStates">
<VisualStateGroup.Transitions>
<VisualTransition GeneratedDuration="0" />
</VisualStateGroup.Transitions>
<VisualState x:Name="CalendarButtonFocused">
<Storyboard>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="FocusVisual" Storyboard.TargetProperty="Visibility"
Duration="0">
<DiscreteObjectKeyFrame KeyTime="0" Value="Visible" />
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
<VisualState x:Name="CalendarButtonUnfocused">
<Storyboard>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="FocusVisual" Storyboard.TargetProperty="Visibility"
Duration="0">
<DiscreteObjectKeyFrame KeyTime="0" Value="Collapsed" />
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
</VisualStateGroup>
</VisualStateManager.VisualStateGroups>
<Rectangle x:Name="SelectedBackground" RadiusX="1" RadiusY="1" Opacity="0" Fill="{TemplateBinding Background}" />
<Rectangle x:Name="Background" RadiusX="1" RadiusY="1" Opacity="0" Fill="{TemplateBinding Background}" />
<ContentControl x:Name="Content" IsTabStop="False" Foreground="#FF333333" Content="{TemplateBinding Content}"
ContentTemplate="{TemplateBinding ContentTemplate}"
HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
FontSize="{TemplateBinding FontSize}" Margin="1,0,1,1" />
<Rectangle x:Name="FocusVisual" Visibility="Collapsed" IsHitTestVisible="false" RadiusX="1" RadiusY="1" Stroke="#FF6DBDD1" />
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<ControlTemplate x:Key="DatePickerTextBoxControlTemplate" TargetType="DatePickerTextBox">
<Grid>
<Grid.Resources>
<SolidColorBrush x:Key="G">#FFAAAAAA</SolidColorBrush>
</Grid.Resources>
<VisualStateManager.VisualStateGroups>
<VisualStateGroup Name="CommonStates" />
<VisualStateGroup Name="WatermarkStates" />
<VisualStateGroup Name="FocusStates" />
</VisualStateManager.VisualStateGroups>
<Border BorderThickness="{TemplateBinding Border.BorderThickness}" Padding="{TemplateBinding Control.Padding}" CornerRadius="1,1,1,1"
BorderBrush="{TemplateBinding Border.BorderBrush}" Background="{TemplateBinding Panel.Background}" Name="Border" Opacity="1">
<Grid Name="WatermarkContent" HorizontalAlignment="{TemplateBinding Control.HorizontalContentAlignment}"
VerticalAlignment="{TemplateBinding Control.VerticalContentAlignment}">
<Border BorderThickness="1,1,1,1" BorderBrush="#FFFFFFFF" Name="ContentElement" />
<Border BorderThickness="1,1,1,1" BorderBrush="#FFFFFFFF" Name="watermark_decorator">
<ContentControl Padding="2,2,2,2" Name="PART_Watermark" Opacity="0" IsHitTestVisible="False" Focusable="False" />
</Border>
<ScrollViewer HorizontalContentAlignment="{TemplateBinding Control.HorizontalContentAlignment}"
VerticalContentAlignment="{TemplateBinding Control.VerticalContentAlignment}"
Name="PART_ContentHost" Margin="0,0,0,0" />
<Border CornerRadius="1,1,1,1" BorderBrush="#FF45D6FA" Name="FocusVisual" Opacity="0" IsHitTestVisible="False" />
</Grid>
</Border>
</Grid>
</ControlTemplate>
<Style x:Key="DatePickerCalendarStyle"
TargetType="{x:Type Calendar}"
BasedOn="{StaticResource {x:Type Calendar}}" />
<!--The template for the button that displays the calendar.-->
<Style x:Key="DropDownButtonStyle" TargetType="Button">
<!-- eliminated-->
</Style>
<!--DatePicker-->
<Style TargetType="{x:Type DatePicker}" BasedOn="{StaticResource baseStyle}">
<!-- eliminated-->
</Style>
</ResourceDictionary>
注意：我已经删除了一些不是问题所必需的样式，因为stackoverflow.com不允许我有超过30000的字符。
我收到运行时错误：将值添加到类型＆＃39; System.Windows.ResourceDictionary＆＃39;的字典中。抛出异常。
当我进入内部异常时，我得到：{＆＃34; Key不能为空。\ r \ nParameter name：key＆＃34;}
这是内部异常的堆栈跟踪：
at System.Collections.Hashtable.Insert(Object key, Object nvalue, Boolean add)
at System.Collections.Hashtable.Add(Object key, Object value)
at System.Windows.ResourceDictionary.AddWithoutLock(Object key, Object value)
at System.Windows.ResourceDictionary.Add(Object key, Object value)
at System.Xaml.Schema.XamlTypeInvoker.AddToDictionary(Object instance, Object key, Object item)
at MS.Internal.Xaml.Runtime.ClrObjectRuntime.AddToDictionary(Object collection, XamlType dictionaryType, Object value, XamlType valueXamlType, Object key)
答案 0 :(得分：2)
您的某些样式缺少x:Key属性。根据{{3}}样式，在大多数情况下，应具有该属性。