WPF Grid Show/Hide Column

Question

I have the following layout in my grid

<Grid>
    <Grid.RowDefinitions >
        <RowDefinition Height="50" />
        <RowDefinition />
    </Grid.RowDefinitions>
    <Button Click="Button_Click"  Grid.Row="0" Width="50" Grid.Column="2" Content="Test" />
    <Grid Grid.Row="1">
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="120" />
        <ColumnDefinition  />
        <ColumnDefinition Width="Auto"  />
    </Grid.ColumnDefinitions>
    <StackPanel Grid.Column="0" Grid.Row="1" Background="red" />
    <StackPanel Grid.Column="1" Grid.Row="1" Background="Blue" />
    <GridSplitter x:Name="gs"  Grid.Column="1" Grid.Row="1" Width="10" />
    <StackPanel x:Name="green" MinWidth="100" Grid.Column="2" Grid.Row="1" Background="Green" />
   </Grid>
</Grid>

I essentially want this layout when the button is pressed:

   <StackPanel Grid.Column="0" Grid.Row="1" Background="red" />
    <StackPanel Grid.Column="1" Grid.ColumnSpan="2" Grid.Row="1" Background="Blue" />
    <!--<GridSplitter x:Name="gs"  Grid.Column="1" Grid.Row="1" Width="10" />
    <StackPanel x:Name="green" MinWidth="100" Grid.Column="2" Grid.Row="1" Background="Green" />-->

And this layout when the button is pressed again:

    <StackPanel Grid.Column="0" Grid.Row="1" Background="red" />
    <StackPanel Grid.Column="1" Grid.ColumnSpan="1" Grid.Row="1" Background="Blue" />
    <GridSplitter x:Name="gs"  Grid.Column="1" Grid.Row="1" Width="10" />
    <StackPanel x:Name="green" MinWidth="100" Grid.Column="2" Grid.Row="1" Background="Green" />

How Can I make the gridsplitter and last panel disappear, and have the panel in the middle column fill it's place? (and vice-versa) Is there a way to change the column span at runtime?

Thanks!

Answer 1

You can use triggers or you can use a storyboard/animation the fires when you button is clicked.

you want to do something like this.....

<Window.Resources>

        <Storyboard x:Key="OnClick1">
            <DoubleAnimationUsingKeyFrames BeginTime="00:00:00" Storyboard.TargetName="gs" Storyboard.TargetProperty="(FrameworkElement.Width)">
                <SplineDoubleKeyFrame KeyTime="00:00:00.5000000" Value="0"/>
            </DoubleAnimationUsingKeyFrames>
            <DoubleAnimationUsingKeyFrames BeginTime="00:00:00" Storyboard.TargetName="green" Storyboard.TargetProperty="(FrameworkElement.MinWidth)">
                <SplineDoubleKeyFrame KeyTime="00:00:00.5000000" Value="0"/>
            </DoubleAnimationUsingKeyFrames>
        </Storyboard>

    </Window.Resources>
    <Window.Triggers>
        <EventTrigger RoutedEvent="ButtonBase.Click" SourceName="button">
            <BeginStoryboard Storyboard="{StaticResource OnClick1}"/>
        </EventTrigger>
    </Window.Triggers>

in order to reverse this animation, you should use something to maintain state, say use a ToggleButton and use the ToggleButton.Checked && ToggleButton.Unchecked routed events. Or, add a dependency property to your codebehind that maintains the state.

I think the main problem is remembering to change the MinWidth attribute as well. MinWidth will override actual width.