Setter中无法识别或访问Path.Data属性

Question

I am hosting a Path inside a Button and want to dynamically change the Data property based on the WindowState of the window that contains the control and thus I ended up with the following XAML code:

<Path SnapsToDevicePixels="True" Data="F1M0,0L0,9 9,9 9,0 0,0 0,3 8,3 8,8 1,8 1,3z"
    Fill="Black">
    <Path.Style>
        <Style>
            <Style.Triggers>
                <DataTrigger Binding="{Binding RelativeSource={RelativeSource AncestorType={x:Type system:Window}}, Path=WindowState}" Value="Maximized">
                    <Setter Property="Data" Value="F1M0,10L0,3 3,3 3,0 10,0 10,2 4,2 4,3 7,3 7,6 6,6 6,5 1,5 1,10z M1,10L7,10 7,7 10,7 10,2 9,2 9,6 6,6 6,9 1,9z" />
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </Path.Style>
</Path>

Unfortunately I get the error message The member "Data" is not recognized or is not accesible. and I did not understand why this error occurs and neither was I able to find a workaround.

Answer 1

you are missing TargetType .

also note that if you set local value for Data , then a setter from trigger won't be able to change it, so you need a setter in a style

<Path SnapsToDevicePixels="True" Fill="Black">
    <Path.Style>
        <Style TargetType="Path">
            <Setter Property="Data" Value="F1M0,0L0,9 9,9 9,0 0,0 0,3 8,3 8,8 1,8 1,3z"/>
            <Style.Triggers>
                <DataTrigger Binding="{Binding RelativeSource={RelativeSource AncestorType={x:Type system:Window}}, Path=WindowState}" Value="Maximized">
                    <Setter Property="Data" Value="F1M0,10L0,3 3,3 3,0 10,0 10,2 4,2 4,3 7,3 7,6 6,6 6,5 1,5 1,10z M1,10L7,10 7,7 10,7 10,2 9,2 9,6 6,6 6,9 1,9z" />
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </Path.Style>
</Path>