Expand/Collapse all expanders

Question

I have a list of expanders which I want to control its expanded state(IsExpanded) with global toggle button which should toggle between expanded/collapsed state.

The solution which I have got so far does that by binding the expander's IsExpanded state to the togglebutton's IsChecked state. This works as long as I dont manually dont toggle the expanders. Once I do that those particular expanders dont respect the binding (toggle button's IsChecked state).

Any idea why? and is there a clean solution in XAML for this?

<Page
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
  <Grid>  
  <StackPanel>
    <ToggleButton Name="ExpandAll">Toggle</ToggleButton>  
    <Expander IsExpanded="{Binding ElementName=ExpandAll,Path=IsChecked, Mode=OneWay}">
      Hai
    </Expander>
    <Expander IsExpanded="{Binding ElementName=ExpandAll,Path=IsChecked, Mode=OneWay}">
      Hello
    </Expander>
    <Expander IsExpanded="{Binding ElementName=ExpandAll,Path=IsChecked, Mode=OneWay}">
      Weird
    </Expander>
    </StackPanel>
  </Grid>
</Page>

Answer 1

I know that this post is very old. Just posting this for anyone else who comes across. The below code worked for me.

<Expander IsExpanded="{Binding ElementName=ExpandAll, Path=IsChecked, UpdateSourceTrigger=Explicit}">
</Expander>

This works when the expanders are generated dynamically, for example inside a DataGrid.RowDetailsTemplate.