xaml - LongListMultiSelector 中的项目之间的空间

Question

在我的 LongListMultiSelector ，如何设置项目之间的垂直空间，使其不会被选择矩形覆盖？只需在下面的 XAML 中添加一个边距，该边距就会被矩形覆盖。

<toolkit:LongListMultiSelector ItemsSource="{Binding Items}">
    <toolkit:LongListMultiSelector.ItemTemplate>
        <DataTemplate>
            <TextBlock Text="Some Text" Margin="0,0,0,50" />
        </DataTemplate>
    </toolkit:LongListMultiSelector.ItemTemplate>
</toolkit:LongListMultiSelector>

显示当我尝试选择一个项目时它的行为方式的图片。 (注意蓝色矩形)


这是一个标准邮件应用程序的示例，其中项目有一些空间，但选择矩形没有覆盖它。 (这就是我要的)

Answer 1

这是关于基本 XAML 概念的一个非常重要的问题:ItemsControl 数据绑定(bind)。 C# 中的所有 ItemsControls 都能够获取数据类(称为“Items”)并将它们转换为可视 UIElements(称为“Containers”)。例如，ListBox 可以从其 ItemSource 中获取项目，创建新的 ListBoxItems 并将每个项目设置为其容器的 DataContext。这基本上就是所有 ItemsControl 的数据绑定(bind)工作方式。

为什么这很有趣？因为 LongListMultiSelector 是另一个 ItemsControl，它会生成 LongListMultiSelectorItems。在 ListBoxItem 和 LongListMultiSelectorItem 的情况下，实例化的 DataTemplate 都嵌套在 ItemTemplate 内，它只是容器的一部分。但是，您无法从 DataTemplate 内部控制容器的属性。这就是为什么您在这里所做的一切似乎都不起作用的原因。

解决方案:使用 ItemContainerStyle 更改容器本身的属性。

1)在具有以下 C# 和 XAML 代码的项目中打开混合:

this.DataContext = "foo bar baz".Split(' ');

<Toolkit:LongListMultiSelector ItemsSource="{Binding}">
    <Toolkit:LongListMultiSelector.ItemTemplate>
        <DataTemplate>
            <TextBlock Text="{Binding}" />
        </DataTemplate>
    </Toolkit:LongListMultiSelector.ItemTemplate>
</Toolkit:LongListMultiSelector>

2) 选择 LongListMultiSelector。在顶部菜单上选择“对象--> 编辑附加样式--> 编辑ItemContainerSyle--> 创建空”并点击“确定”。

3) 由于 LongListMultiSelectorItem 在 Grid 和 List 之间更改了 ItemContainerStyle，您需要手动替换所有 <Setter />您的样式中的元素以及以下样式之一中的所有 setter 。例如，我将 LongListMultiSelectorItemListStyle 中的所有 setter 复制到我的新 LongListMultiSelectorItemStyle1 中。

<Style x:Key="LongListMultiSelectorItemGridStyle" TargetType="controls:LongListMultiSelectorItem">
    <Setter Property="Background" Value="Transparent"/>
    <Setter Property="BorderThickness" Value="0"/>
    <Setter Property="BorderBrush" Value="Transparent"/>
    <Setter Property="Padding" Value="0"/>
    <Setter Property="HorizontalContentAlignment" Value="Stretch"/>
    <Setter Property="VerticalContentAlignment" Value="Stretch"/>
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="controls:LongListMultiSelectorItem">
                <Border x:Name="LayoutRoot" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" HorizontalAlignment="{TemplateBinding HorizontalAlignment}" VerticalAlignment="{TemplateBinding VerticalAlignment}">
                    <VisualStateManager.VisualStateGroups>
                        <VisualStateGroup x:Name="CommonStates">
                            <VisualState x:Name="Normal"/>
                            <VisualState x:Name="MouseOver"/>
                            <VisualState x:Name="Disabled">
                                <Storyboard>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="LayoutRoot">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource TransparentBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <DoubleAnimation Duration="0" To=".5" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="ContentContainer"/>
                                </Storyboard>
                            </VisualState>
                        </VisualStateGroup>
                        <VisualStateGroup x:Name="SelectionStates">
                            <VisualState x:Name="Unselected"/>
                            <VisualState x:Name="Selected">
                                <Storyboard>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)" Storyboard.TargetName="SelectionTriangle">
                                        <DiscreteObjectKeyFrame KeyTime="0">
                                            <DiscreteObjectKeyFrame.Value>
                                                <Visibility>Visible</Visibility>
                                            </DiscreteObjectKeyFrame.Value>
                                        </DiscreteObjectKeyFrame>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)" Storyboard.TargetName="SelectionCheck">
                                        <DiscreteObjectKeyFrame KeyTime="0">
                                            <DiscreteObjectKeyFrame.Value>
                                                <Visibility>Visible</Visibility>
                                            </DiscreteObjectKeyFrame.Value>
                                        </DiscreteObjectKeyFrame>
                                    </ObjectAnimationUsingKeyFrames>
                                </Storyboard>
                            </VisualState>
                        </VisualStateGroup>
                        <VisualStateGroup x:Name="HasSelectionStates">
                            <VisualState x:Name="Opened">
                                <Storyboard>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)" Storyboard.TargetName="SelectionRectangle">
                                        <DiscreteObjectKeyFrame KeyTime="0">
                                            <DiscreteObjectKeyFrame.Value>
                                                <Visibility>Visible</Visibility>
                                            </DiscreteObjectKeyFrame.Value>
                                        </DiscreteObjectKeyFrame>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)" Storyboard.TargetName="OuterCover">
                                        <DiscreteObjectKeyFrame KeyTime="0">
                                            <DiscreteObjectKeyFrame.Value>
                                                <Visibility>Visible</Visibility>
                                            </DiscreteObjectKeyFrame.Value>
                                        </DiscreteObjectKeyFrame>
                                    </ObjectAnimationUsingKeyFrames>
                                </Storyboard>
                            </VisualState>
                            <VisualState x:Name="Closed"/>
                        </VisualStateGroup>
                    </VisualStateManager.VisualStateGroups>
                    <Grid Margin="1" >
                        <ContentControl x:Name="ContentContainer"
                                Margin="3"
                                ContentTemplate="{TemplateBinding ContentTemplate}"
                                Content="{TemplateBinding Content}"
                                Foreground="{TemplateBinding Foreground}"
                                HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
                                VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"
                                />
                        <Rectangle x:Name="SelectionRectangle" Visibility="Collapsed"
                                       Stroke="{StaticResource PhoneAccentBrush}" StrokeThickness="2"/>
                        <Polyline x:Name="SelectionTriangle" Visibility="Collapsed"
                                HorizontalAlignment="Right" VerticalAlignment="Top"
                                Points="50,0 50,50 0,0"
                                Fill="{StaticResource PhoneAccentBrush}"
                            />
                        <Polyline x:Name="SelectionCheck" Visibility="Collapsed"
                                Margin="5" HorizontalAlignment="Right" VerticalAlignment="Top"
                                Points="40,0 43,3 28,18 18,8 21,5 28,12"
                                Fill="{StaticResource PhoneForegroundBrush}"
                                />
                        <Grid x:Name="OuterCover" IsHitTestVisible="True" Visibility="Collapsed" Background="Transparent" VerticalAlignment="Stretch" HorizontalAlignment="Stretch"/>
                    </Grid>
                </Border>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

<Style x:Key="LongListMultiSelectorItemListStyle" TargetType="controls:LongListMultiSelectorItem">
    <Style.Setters>
        <Setter Property="Background" Value="{StaticResource PhoneAccentBrush}"/>
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="controls:LongListMultiSelectorItem">
                    <Grid MinHeight="52">
                        <Grid.Resources>
                            <ExponentialEase EasingMode="EaseIn" Exponent="8" x:Key="ExponentialEaseIn"/>
                            <QuadraticEase EasingMode="EaseOut" x:Key="QuadraticEaseOut"/>
                        </Grid.Resources>
                        <VisualStateManager.VisualStateGroups>
                            <VisualStateGroup x:Name="SelectionEnabledStates">
                                <VisualStateGroup.Transitions>
                                    <VisualTransition x:Name="ClosedToExposed" 
                                                      From="Closed" To="Exposed"
                                                      GeneratedDuration="0:0:0.30">
                                        <Storyboard>
                                            <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Opacity)" 
                                                                           Storyboard.TargetName="OuterHintPanel">
                                                <EasingDoubleKeyFrame KeyTime="0:0:0.0" Value="0.0" EasingFunction="{StaticResource QuadraticEaseOut}"/>
                                                <EasingDoubleKeyFrame KeyTime="0:0:0.30" Value="1.0" EasingFunction="{StaticResource QuadraticEaseOut}"/>
                                            </DoubleAnimationUsingKeyFrames>
                                        </Storyboard>
                                    </VisualTransition>
                                    <VisualTransition x:Name="ExposedToClosed" 
                                                      From="Exposed" To="Closed"
                                                      GeneratedDuration="0:0:0.30">
                                        <Storyboard>
                                            <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Opacity)" 
                                                                           Storyboard.TargetName="OuterHintPanel">
                                                <EasingDoubleKeyFrame KeyTime="0:0:0.0" Value="1.0" EasingFunction="{StaticResource QuadraticEaseOut}"/>
                                                <EasingDoubleKeyFrame KeyTime="0:0:0.30" Value="0.0" EasingFunction="{StaticResource QuadraticEaseOut}"/>
                                            </DoubleAnimationUsingKeyFrames>
                                        </Storyboard>
                                    </VisualTransition>
                                    <VisualTransition x:Name="ExposedToOpened"
                                                      From="Exposed" To="Opened"
                                                      GeneratedDuration="0:0:0.30">
                                        <Storyboard>
                                            <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.RenderTransform).(CompositeTransform.TranslateX)" 
                                                                           Storyboard.TargetName="SelectBox">
                                                <EasingDoubleKeyFrame KeyTime="0:0:0.0" Value="-58" EasingFunction="{StaticResource ExponentialEaseIn}"/>
                                                <EasingDoubleKeyFrame KeyTime="0:0:0.15" Value="0" EasingFunction="{StaticResource ExponentialEaseIn}"/>
                                            </DoubleAnimationUsingKeyFrames>
                                            <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.RenderTransform).(CompositeTransform.TranslateX)" 
                                                                           Storyboard.TargetName="Presenter">
                                                <EasingDoubleKeyFrame KeyTime="0:0:0.0" Value="24" EasingFunction="{StaticResource ExponentialEaseIn}"/>
                                                <EasingDoubleKeyFrame KeyTime="0:0:0.15" Value="86" EasingFunction="{StaticResource ExponentialEaseIn}"/>
                                            </DoubleAnimationUsingKeyFrames>
                                            <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Opacity)" 
                                                                           Storyboard.TargetName="OuterHintPanel">
                                                <EasingDoubleKeyFrame KeyTime="0:0:0.0" Value="1.0" EasingFunction="{StaticResource QuadraticEaseOut}"/>
                                                <EasingDoubleKeyFrame KeyTime="0:0:0.30" Value="0.0" EasingFunction="{StaticResource QuadraticEaseOut}"/>
                                            </DoubleAnimationUsingKeyFrames>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)" 
                                                                           Storyboard.TargetName="SelectBox">
                                                <DiscreteObjectKeyFrame KeyTime="0:0:0.0" Value="Visible"/>
                                            </ObjectAnimationUsingKeyFrames>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.IsHitTestVisible)" 
                                                                           Storyboard.TargetName="OuterHintPanel">
                                                <DiscreteObjectKeyFrame KeyTime="0:0:0" Value="False"/>
                                            </ObjectAnimationUsingKeyFrames>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.IsHitTestVisible)" 
                                                                           Storyboard.TargetName="InnerHintPanel">
                                                <DiscreteObjectKeyFrame KeyTime="0:0:0" Value="False"/>
                                            </ObjectAnimationUsingKeyFrames>
                                        </Storyboard>
                                    </VisualTransition>
                                    <VisualTransition x:Name="ClosedToOpened"
                                                      From="Closed" To="Opened"
                                                      GeneratedDuration="0:0:0.15">
                                        <Storyboard>
                                            <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.RenderTransform).(CompositeTransform.TranslateX)" 
                                                                           Storyboard.TargetName="SelectBox">
                                                <EasingDoubleKeyFrame KeyTime="0:0:0.0" Value="-58" EasingFunction="{StaticResource ExponentialEaseIn}"/>
                                                <EasingDoubleKeyFrame KeyTime="0:0:0.15" Value="0" EasingFunction="{StaticResource ExponentialEaseIn}"/>
                                            </DoubleAnimationUsingKeyFrames>
                                            <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.RenderTransform).(CompositeTransform.TranslateX)" 
                                                                           Storyboard.TargetName="Presenter">
                                                <EasingDoubleKeyFrame KeyTime="0:0:0.0" Value="24" EasingFunction="{StaticResource ExponentialEaseIn}"/>
                                                <EasingDoubleKeyFrame KeyTime="0:0:0.15" Value="86" EasingFunction="{StaticResource ExponentialEaseIn}"/>
                                            </DoubleAnimationUsingKeyFrames>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)" 
                                                                           Storyboard.TargetName="SelectBox">
                                                <DiscreteObjectKeyFrame KeyTime="0:0:0.0" Value="Visible"/>
                                            </ObjectAnimationUsingKeyFrames>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.IsHitTestVisible)" 
                                                                           Storyboard.TargetName="OuterHintPanel">
                                                <DiscreteObjectKeyFrame KeyTime="0:0:0" Value="False"/>
                                            </ObjectAnimationUsingKeyFrames>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.IsHitTestVisible)" 
                                                                           Storyboard.TargetName="InnerHintPanel">
                                                <DiscreteObjectKeyFrame KeyTime="0:0:0" Value="False"/>
                                            </ObjectAnimationUsingKeyFrames>
                                        </Storyboard>
                                    </VisualTransition>
                                    <VisualTransition x:Name="OpenedToClosed"
                                                      From="Opened" To="Closed"
                                                      GeneratedDuration="0:0:0.15">
                                        <Storyboard>
                                            <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.RenderTransform).(CompositeTransform.TranslateX)" 
                                                                           Storyboard.TargetName="SelectBox">
                                                <EasingDoubleKeyFrame KeyTime="0:0:0.0" Value="0" EasingFunction="{StaticResource ExponentialEaseIn}"/>
                                                <EasingDoubleKeyFrame KeyTime="0:0:0.15" Value="-58" EasingFunction="{StaticResource ExponentialEaseIn}"/>
                                            </DoubleAnimationUsingKeyFrames>
                                            <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.RenderTransform).(CompositeTransform.TranslateX)" 
                                                                           Storyboard.TargetName="Presenter">
                                                <EasingDoubleKeyFrame KeyTime="0:0:0.0" Value="86" EasingFunction="{StaticResource ExponentialEaseIn}"/>
                                                <EasingDoubleKeyFrame KeyTime="0:0:0.15" Value="24" EasingFunction="{StaticResource ExponentialEaseIn}"/>
                                            </DoubleAnimationUsingKeyFrames>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)" 
                                                                           Storyboard.TargetName="SelectBox">
                                                <DiscreteObjectKeyFrame KeyTime="0:0:0.15" Value="Collapsed"/>
                                            </ObjectAnimationUsingKeyFrames>
                                        </Storyboard>
                                    </VisualTransition>
                                </VisualStateGroup.Transitions>
                                <VisualStateGroup.States>
                                    <VisualState x:Name="Closed"/>
                                    <VisualState x:Name="Exposed">
                                        <Storyboard>
                                            <DoubleAnimation Storyboard.TargetProperty="(UIElement.Opacity)" 
                                                             Storyboard.TargetName="OuterHintPanel"
                                                             Duration="0" To="1.0"/>
                                        </Storyboard>
                                    </VisualState>
                                    <VisualState x:Name="Opened">
                                        <Storyboard>
                                            <DoubleAnimation Storyboard.TargetProperty="(UIElement.RenderTransform).(CompositeTransform.TranslateX)" 
                                                             Storyboard.TargetName="SelectBox"
                                                             Duration="0" To="0"/>
                                            <DoubleAnimation Storyboard.TargetProperty="(UIElement.RenderTransform).(CompositeTransform.TranslateX)" 
                                                             Storyboard.TargetName="Presenter"
                                                             Duration="0" To="86"/>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)" 
                                                                           Storyboard.TargetName="SelectBox">
                                                <DiscreteObjectKeyFrame KeyTime="0:0:0" Value="Visible"/>
                                            </ObjectAnimationUsingKeyFrames>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)" 
                                                                           Storyboard.TargetName="OuterCover">
                                                <DiscreteObjectKeyFrame KeyTime="0:0:0" Value="Visible"/>
                                            </ObjectAnimationUsingKeyFrames>
                                            <DoubleAnimation Storyboard.TargetProperty="(UIElement.Opacity)" 
                                                             Storyboard.TargetName="OuterHintPanel"
                                                             Duration="0" To="0.0"/>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.IsHitTestVisible)" 
                                                                           Storyboard.TargetName="OuterHintPanel">
                                                <DiscreteObjectKeyFrame KeyTime="0:0:0" Value="False"/>
                                            </ObjectAnimationUsingKeyFrames>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.IsHitTestVisible)" 
                                                                           Storyboard.TargetName="InnerHintPanel">
                                                <DiscreteObjectKeyFrame KeyTime="0:0:0" Value="False"/>
                                            </ObjectAnimationUsingKeyFrames>
                                        </Storyboard>
                                    </VisualState>
                                </VisualStateGroup.States>
                            </VisualStateGroup>
                        </VisualStateManager.VisualStateGroups>
                        <Grid HorizontalAlignment="Stretch">
                            <Grid.ColumnDefinitions>
                                <ColumnDefinition Width="*"/>
                                <ColumnDefinition Width="Auto"/>
                            </Grid.ColumnDefinitions>
                            <Grid Grid.Column="0" HorizontalAlignment="Stretch" primitives:ClipToBounds.IsEnabled="True">
                                <ContentPresenter x:Name="Presenter">
                                    <ContentPresenter.RenderTransform>
                                        <CompositeTransform TranslateX="24"/>
                                    </ContentPresenter.RenderTransform>
                                </ContentPresenter>
                            </Grid>
                            <Rectangle x:Name="InnerHintPanel" Grid.Column="0" Width="24"
                                       Height="{TemplateBinding HintPanelHeight}"
                                       HorizontalAlignment="Left"
                                       Fill="Transparent"
                                       StrokeThickness="0">
                                <Rectangle.RenderTransform>
                                    <CompositeTransform TranslateX="24"/>
                                </Rectangle.RenderTransform>
                            </Rectangle>
                            <ContentControl x:Name="InfoPresenter" Grid.Column="1" 
                                            VerticalAlignment="Top"
                                            Content="{TemplateBinding ContentInfo}"
                                            ContentTemplate="{TemplateBinding ContentInfoTemplate}"/>
                        </Grid>
                        <Rectangle x:Name="OuterHintPanel" Width="24"
                                   HorizontalAlignment="Left"
                                   Height="{TemplateBinding HintPanelHeight}"
                                   Fill="{TemplateBinding Background}"
                                   StrokeThickness="0" Opacity="0.0"/>
                        <Grid x:Name="OuterCover" IsHitTestVisible="True"
                              Visibility="Collapsed" Background="Transparent"/>
                        <Canvas HorizontalAlignment="Left">
                            <CheckBox x:Name="SelectBox" VerticalAlignment="Top" Margin="12,-20,5,0" Visibility="Collapsed"
                                      IsChecked="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=IsSelected, Mode=TwoWay}">
                                <CheckBox.RenderTransform>
                                    <CompositeTransform TranslateX="-58"/>
                                </CheckBox.RenderTransform>
                            </CheckBox>
                        </Canvas>
                    </Grid>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style.Setters>
</Style>

4) 确保修复 XMLNS 引用，如工具包和原语。

5) 现在您可以编辑样式了。从顶部菜单转到“对象--> 编辑附加样式--> 编辑ItemContainerStyle--> 编辑当前”。

6) 将 ItemContainerStyle Margin 从“0”设置为“0, 0, 50, 0”。



当我们使用修改后的 ItemContainerStyle 运行 LongListMultiSelector 时，我们可以看到项目之间的以下空间:



请务必记住，ItemContainerStyle 是我们武器库中非常强大的武器。我们可以使用 ItemContainerStyle 来编辑容器的样式，甚至是它们的模板。