资源字典中的运行时错误： { "Key cannot be null.rnParameter name: key" }

Question

我有一个WPF应用程序。我有一个名为Metro.xaml的资源字典。我为这个资源字典添加了一些样式。在我为日历及其部分添加控制模板之前，它运行得很好。

这是名为Metro.xaml:的资源字典

<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必要的样式，因为stackoverflow.com不允许我有超过30000个字符。

我收到一个运行时错误：向"System.Windows.ResourceDictionary"类型的字典添加值引发了异常。

当我转到内部异常时，我得到：｛"Key不能为null。\r\n参数名称：Key"｝

以下是内部异常的堆栈：

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)

Answer 1

某些样式缺少x:Key属性。根据这篇关于MSDN的文章，样式在大多数情况下都应该具有该属性。