How do I correctly bind a Popup to a ToggleButton?

Question

I am trying to do something that seems relatively simple and logic from a user interface level but I have one bug that is very annoying. I have a ToggleButton a

Answer 1

Stephans answers has the disadvantage, that the desired behaviour of closing the popup whenever it loses focus also disappears.

I solved it by disabling the toggle-button when the popup is open. An alternative would be to use the IsHitTestVisible Property instead of is enabled:

    <ToggleButton x:Name="TogglePopupButton" Content="My Popup Toggle Button" Width="100"  IsEnabled="{Binding ElementName=ToggledPopup, Path=IsOpen, Converter={StaticResource BoolToInvertedBoolConverter}}"/>
    <Popup x:Name="ToggledPopup" StaysOpen="False" IsOpen="{Binding IsChecked, ElementName=TogglePopupButton, Mode=TwoWay}">
        <Border Width="100" Height="200" Background="White" BorderThickness="1" BorderBrush="Black">
            <TextBlock>This is a test</TextBlock>
        </Border>                
    </Popup>

The converter looks like this:

public class BoolToInvertedBoolConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        if (value is bool)
        {
            bool boolValue = (bool)value;
            return !boolValue;
        }
        else
            return false;
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException("ConvertBack() of BoolToInvertedBoolConverter is not implemented");
    }
}

Answer 2

Solution without IValueConverter:

<Grid>
    <ToggleButton x:Name="TogglePopupButton" Content="My Popup Toggle Button" Width="100" >
        <ToggleButton.Style>
            <Style TargetType="{x:Type ToggleButton}">
                <Setter Property="IsHitTestVisible" Value="True"/>
                <Style.Triggers>
                    <DataTrigger Binding="{Binding ElementName=Popup, Path=IsOpen}" Value="True">
                        <Setter Property="IsHitTestVisible" Value="False"/>
                    </DataTrigger>
                </Style.Triggers>
            </Style>
        </ToggleButton.Style>
    </ToggleButton>

    <Popup StaysOpen="false" IsOpen="{Binding IsChecked, ElementName=TogglePopupButton, Mode=TwoWay}"
               PlacementTarget="{Binding ElementName=TogglePopupButton}" PopupAnimation="Slide" 
           x:Name="Popup">
        <Border Width="100" Height="200" Background="White" BorderThickness="1" BorderBrush="Black">
            <TextBlock>This is a test</TextBlock>
        </Border>
    </Popup>
</Grid>

Answer 3

On the ToggleButton set the Property ClickMode="Press"apixeltoofar

Answer 4

Set StaysOpen="True" for your Popup

From MSDN:

Gets or sets a value that indicates whether the Popup control closes when the control is no longer in focus.

[...]

true if the Popup control closes when IsOpen property is set to false;

false if the Popup control closes when a mouse or keyboard event occurs outside the Popup control.