0
votes

I would like to unselect an item within a LongListSelector programmatically, but I am unsure of how to accomplish this task. I have the selection working correctly using the SelectionChanged event handler. My issue arises when leaving the page and then coming back, I am clearing the values used in the SelectionChanged event because they may change, but if I need to reselect the item in the LongListSelector, the event does not fire because it thinks it is already selected.

MainPage.xaml

<phone:PhoneApplicationPage.Resources>

    <Style x:Key="PhoneButtonBase" TargetType="ButtonBase">
        <Setter Property="Background" Value="Transparent"/>
        <Setter Property="BorderBrush" Value="{StaticResource PhoneForegroundBrush}"/>
        <Setter Property="Foreground" Value="{StaticResource PhoneForegroundBrush}"/>
        <Setter Property="BorderThickness" Value="{StaticResource PhoneBorderThickness}"/>
        <Setter Property="FontFamily" Value="{StaticResource PhoneFontFamilySemiBold}"/>
        <Setter Property="FontSize" Value="{StaticResource PhoneFontSizeMedium}"/>
        <Setter Property="Padding" Value="10,5,10,6"/>
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="ButtonBase">
                    <Grid Background="Transparent">
                        <VisualStateManager.VisualStateGroups>
                            <VisualStateGroup x:Name="CommonStates">
                                <VisualState x:Name="Normal"/>
                                <VisualState x:Name="MouseOver"/>
                                <VisualState x:Name="Pressed">
                                    <Storyboard>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="ContentContainer">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PhoneButtonBasePressedForegroundBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="ButtonBackground">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PhoneAccentBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                    </Storyboard>
                                </VisualState>
                                <VisualState x:Name="Disabled">
                                    <Storyboard>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="ContentContainer">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PhoneDisabledBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="ButtonBackground">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PhoneDisabledBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="ButtonBackground">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="Transparent"/>
                                        </ObjectAnimationUsingKeyFrames>
                                    </Storyboard>
                                </VisualState>
                            </VisualStateGroup>
                        </VisualStateManager.VisualStateGroups>
                        <Border x:Name="ButtonBackground" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" CornerRadius="0" Margin="{StaticResource PhoneTouchTargetOverhang}">
                            <ContentControl x:Name="ContentContainer" ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" Foreground="{TemplateBinding Foreground}" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" Padding="{TemplateBinding Padding}" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"/>
                        </Border>
                    </Grid>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
    <Style x:Key="PhoneRadioButtonCheckBoxBase" BasedOn="{StaticResource PhoneButtonBase}" TargetType="ToggleButton">
        <Setter Property="Background" Value="{StaticResource PhoneRadioCheckBoxBrush}"/>
        <Setter Property="BorderBrush" Value="{StaticResource PhoneRadioCheckBoxBorderBrush}"/>
        <Setter Property="FontSize" Value="{StaticResource PhoneFontSizeMedium}"/>
        <Setter Property="FontFamily" Value="{StaticResource PhoneFontFamilyNormal}"/>
        <Setter Property="HorizontalContentAlignment" Value="Left"/>
        <Setter Property="VerticalContentAlignment" Value="Center"/>
        <Setter Property="Padding" Value="0"/>
    </Style>
    <Style x:Key="RadioButtonStyle1" BasedOn="{StaticResource PhoneRadioButtonCheckBoxBase}" TargetType="RadioButton">
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="RadioButton">
                    <Grid Background="Transparent">
                        <VisualStateManager.VisualStateGroups>
                            <VisualStateGroup x:Name="CommonStates">
                                <VisualState x:Name="Normal"/>
                                <VisualState x:Name="MouseOver"/>
                                <VisualState x:Name="Pressed"/>
                                <VisualState x:Name="Disabled">
                                    <Storyboard>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="ContentContainer">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PhoneDisabledBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                    </Storyboard>
                                </VisualState>
                            </VisualStateGroup>
                            <VisualStateGroup x:Name="CheckStates">
                                <VisualState x:Name="Checked"/>
                                <VisualState x:Name="Unchecked"/>
                                <VisualState x:Name="Indeterminate"/>
                            </VisualStateGroup>
                        </VisualStateManager.VisualStateGroups>
                        <ContentControl x:Name="ContentContainer" ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" Foreground="{TemplateBinding Foreground}" FontSize="{TemplateBinding FontSize}" FontFamily="{TemplateBinding FontFamily}" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" Padding="{TemplateBinding Padding}" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"/>
                    </Grid>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

</phone:PhoneApplicationPage.Resources>

..

<phone:LongListSelector x:Name="Recent" Margin="0,0,0,72"
                                    LayoutMode="Grid" GridCellSize="108,108" 
                                    SelectionChanged="recent_SelectionChanged">

                <phone:LongListSelector.ItemTemplate>
                    <DataTemplate>
                        <ContentControl HorizontalAlignment="Stretch" HorizontalContentAlignment="Left">
                            <ContentControl.Resources>
                                <Storyboard x:Name="CheckedStoryboard">
                                    <ColorAnimation Duration="0" To="#FF1BA1E2" Storyboard.TargetProperty="(Border.BorderBrush).(SolidColorBrush.Color)" Storyboard.TargetName="brd" d:IsOptimized="True"/>
                                </Storyboard>
                            </ContentControl.Resources>
                            <RadioButton x:Name="radioButton" HorizontalAlignment="Stretch" Margin="0,0,0,0" GroupName="A" Background="Black" Style="{StaticResource RadioButtonStyle1}" >
                                <i:Interaction.Triggers>
                                    <i:EventTrigger EventName="Click">
                                        <eim:ControlStoryboardAction Storyboard="{StaticResource CheckedStoryboard}"/>
                                    </i:EventTrigger>
                                    <i:EventTrigger EventName="Unchecked">
                                        <eim:ControlStoryboardAction ControlStoryboardOption="Stop" Storyboard="{StaticResource CheckedStoryboard}"/>
                                    </i:EventTrigger>
                                </i:Interaction.Triggers>
                                <Border x:Name="MyBorder" Background="Transparent">
                                    <Border x:Name="brd" CornerRadius="10" Width="Auto" BorderThickness="3" BorderBrush="Transparent">
                                        <toolkit:ContextMenuService.ContextMenu>
                                            <toolkit:ContextMenu x:Name="imgListContextMenu" Background="{StaticResource PhoneChromeBrush}">                                                                                                        <toolkit:MenuItem Foreground="{StaticResource PhoneForegroundBrush}" Header="{Binding Path=LocalizedResources.MainPage_ContextMenu_Delete, Source={StaticResource LocalizedStrings}}" Click="deleteContextMenuItem_Click"/>
                                            </toolkit:ContextMenu>
                                        </toolkit:ContextMenuService.ContextMenu>
                                        <Viewbox Width="108" Height="108">
                                            <Image x:Name="recentImage" Source="{Binding Source}" Margin="6,6" Width="108"/>
                                        </Viewbox>
                                    </Border>
                                </Border>
                            </RadioButton>
                        </ContentControl>
                    </DataTemplate>
                </phone:LongListSelector.ItemTemplate>

            </phone:LongListSelector>

MainPage.xaml.cs

protected override void OnNavigatedFrom(NavigationEventArgs e)
    {
        base.OnNavigatedFrom(e);

        //if a LongListSElector item is currently selected, unselect it and remove border                
    }   

private void recent_SelectionChanged(object sender, SelectionChangedEventArgs e)
    {
        var item = (sender as LongListSelector).SelectedItem;
        if (item == null)
            return;

        capturedPicture = null; 
        //Get picture
        capturedPicture = (sender as LongListSelector).SelectedItem as CapturedPicture;

        if (capturedPicture != null)
        {                
            currentPhoto.DataContext = null;   
            fileName = null;
            currentPhoto.DataContext = capturedPicture;
            fileName = capturedPicture.FileName;
        }
    }
1
Can you please help me on this stackoverflow.com/questions/22706930/…user2056563

1 Answers

0
votes

To clear the selection, simply set the SelectedItem property to null:

Recent.SelectedItem = null;