Windows Phone 8, finding a checkbox item inside listbox

Question

I have a checkbox inside a stackpanel inside a listbox. I need to set the visibility of that checkbox based on some logical operations, so I need to find that element in listbox.

I am using the following code to find the checkbox on my PageLoad, after the list`s dataSource has been set. But on this listboxItem i get a null value and a exception saying : reference is not a valid visual dependencyobject

private void searchListCheckBoxVisibility()
        //private void SearchList_Loaded(object sender, RoutedEventArgs e)
        {
            try
            {
                ListBoxItem listItem = this.SearchList.ItemContainerGenerator.ContainerFromIndex(2) as ListBoxItem;
                CheckBox targetCheckBox = FindFirstElementInVisualTree<CheckBox>(listItem);
}
}

The following is my xaml :

Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
            <ListBox Margin="13,10,7,10" x:Name="SearchList" DoubleTap="SearchList_DoubleTap">
                <ListBox.ItemTemplate>
                    <DataTemplate>
                        <StackPanel x:Name="searchListPanel" Orientation="Horizontal" Width="400" ScrollViewer.HorizontalScrollBarVisibility="Auto">
                            <StackPanel Orientation="Vertical" Width="340">
                                <StackPanel Orientation="Vertical">
                                    <TextBlock Text="Name : " FontWeight="Bold" Style="{StaticResource ResourceKey=MSFTGuidelines_TextBlock}"/>
                                    <TextBlock Text="{Binding User}" TextWrapping="Wrap" Style="{StaticResource ResourceKey=MSFTGuidelines_TextBlock}"/>
                                </StackPanel>
                                <StackPanel Orientation="Horizontal">
                                    <TextBlock Text="Project : " FontWeight="Bold" Style="{StaticResource ResourceKey=MSFTGuidelines_TextBlock}"/>
                                    <TextBlock Text="{Binding Project}" TextWrapping="Wrap" Style="{StaticResource ResourceKey=MSFTGuidelines_TextBlock}"/>
                                </StackPanel>
                                <StackPanel Orientation="Horizontal">
                                    <TextBlock Text="Status : " FontWeight="Bold" Style="{StaticResource ResourceKey=MSFTGuidelines_TextBlock}"/>
                                    <TextBlock Text="{Binding On_OffBoarded}" TextWrapping="Wrap" Style="{StaticResource ResourceKey=MSFTGuidelines_TextBlock}"/>
                                </StackPanel>
                                <StackPanel Orientation="Horizontal">
                                    <TextBlock Text="Date : " FontWeight="Bold" Style="{StaticResource ResourceKey=MSFTGuidelines_TextBlock}"/>
                                    <TextBlock Text="{Binding DT_On_OffBoarded}" TextWrapping="Wrap" Style="{StaticResource ResourceKey=MSFTGuidelines_TextBlock}"/>
                                </StackPanel>
                                <StackPanel>
                                    <TextBlock Text=""/>
                                </StackPanel>
                            </StackPanel>
                            <CheckBox Width="60" 
                                      x:Name="user_Checkbox" 
                                      Content="" Tag="{Binding ID}" 
                                      Visibility="Collapsed" 
                                      Checked="user_Checkbox_Checked"
                                      Unchecked="user_Checkbox_UnChecked"
                                      Style="{StaticResource ResourceKey=MSFTGuidelinesCheckBox}"
                                      IsChecked="False"

                                      />
                        </StackPanel>
                    </DataTemplate>
                </ListBox.ItemTemplate>
            </ListBox>
        </Grid>

I am stuck at this issue for a while, and it has been getting onto my nerves now, Please help. Thanks in advance.

score 0 · Answer 1 · edited May 23 '17 at 10:26

0

You could simply use the VisualTreeHelper to find a control within your Listbox data template.

Reference: How to access a specific item in a Listbox with DataTemplate?

edited May 23 '17 at 10:26

Community

1
1

answered Nov 23 '14 at 17:41

Kulasangar

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Windows Phone 8, finding a checkbox item inside listbox

1 Answers1