WPF扩展器未扩展

Question

I'd like to create a custom WPF accordion-like control without using WPF toolkit... After some searching it seems like the best approach would be to use an Expander... so I wanted to just see if I could get some sort of basic functionality like getting a row to expand upward to show some content when it is expanded and then to have it collapse and hide that content. It seems like it should be pretty straight-forward but my expander never expands. Here's my basic example:

<Grid Background="Transparent">
    <Grid.RowDefinitions>
        <RowDefinition Height="30"></RowDefinition>
        <RowDefinition Height="Auto"></RowDefinition>
        <RowDefinition Height="1*"></RowDefinition>
        <RowDefinition Height="24"></RowDefinition>
    </Grid.RowDefinitions>
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="215"></ColumnDefinition>
        <ColumnDefinition></ColumnDefinition>
    </Grid.ColumnDefinitions>
    <Expander Grid.Row="3" Grid.ColumnSpan="2" Header="More Options" ExpandDirection="Down" Background="Red" IsExpanded="False">
        <StackPanel Height="300">
            <CheckBox Margin="4" Content="Option 1" />
            <CheckBox Margin="4" Content="Option 2" />
            <CheckBox Margin="4" Content="Option 3" />
        </StackPanel>
    </Expander>
</Grid>

Answer 1

Update your RowDefinitions . Currently, the Row that the Expander is in is hard-coded to have a Height of 24. Make it Auto .

<Grid.RowDefinitions>
    <RowDefinition Height="30"></RowDefinition>
    <RowDefinition Height="Auto"></RowDefinition>
    <RowDefinition Height="1*"></RowDefinition>
    <RowDefinition Height="Auto"></RowDefinition>
</Grid.RowDefinitions>