How to resolve "Items collection must be empty before using itemssource" error?

Question

I have set the datasource for TreeViewAdv and tried to use the context menu and checkbox for treeview items.

<TreeView>
    <TreeViewItem Header="TestedApps"
         ItemsSource="{Binding Scripts}">
        <StackPanel Orientation="Horizontal">
            <StackPanel.ContextMenu>
                <ContextMenu>
                    <MenuItem Header="Play" Click="Play"/>
                </ContextMenu>
            </StackPanel.ContextMenu>
            <CheckBox Margin="0" VerticalAlignment="Center" IsChecked="{Binding IsEnabled, Mode=TwoWay}"/>
            <Rectangle Margin="5 0" Width="12" Height="12" Fill="{Binding Result, Converter={StaticResource ResultConverter}}"/>
            <TextBlock Margin="2 0" Text="{Binding Name}" VerticalAlignment="Center"/>
        </StackPanel>
    </TreeViewItem>
</TreeView>

But it gives me an error "Items collection must be empty before using itemssource". I have visited some articles but could not find the reason for this.

Please anyone let me know how to solve this?

Thanks,

Get rid of all the code inside of the treeviewitem. Parser thinks that your `StackPanel` is your items source. What you need is to take that code and insert it into a `DataTemplate` and then reference it in your TreeViewItem. — XAMlMAX, Dec 27 '17 at 09:09

score 2 · Accepted Answer · answered Dec 27 '17 at 09:11

2

I guess, you need the following:

<TreeView>
    <TreeView.ItemTemplate>
        <DataTemplate>
            <StackPanel>
                ....
            </StackPanel>
        </DataTemplate>
    </TreeView.ItemTemplate>    
</TreeView>

answered Dec 27 '17 at 09:11

JohnyL

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i have tried this. but shows checkboxes only when i expand the node. "{Binding Scripts}" was not displayed. I have used like below – Prithiv Dec 27 '17 at 09:27
Hi @John, Thanks for your suggestion. I have corrected my code. Now its working fine. – Prithiv Dec 27 '17 at 09:58
@Prithiv You're welcome! – JohnyL Dec 27 '17 at 09:59

How to resolve "Items collection must be empty before using itemssource" error?

1 Answers1