Expand/Collapse grid column on WPF expander click event - wpf

Question

I have a MVVM application. In main window I have put below grid with 2 columns. In column 2 I have placed an WPF expander and I set it as collapsed by default (IsExpanded="False"). When application executes I would like grid column 1 to fill the entire width of the grid and grid column 2 with width 0 (collapsed). So when I click in the expander I want grid column 2 to expand to take 0.47* of width. Then if I click the expander again, I would like grid column 1 to fill the entire width of the grid and grid column 2 to be collapsed (width=0). How can I do this? Below code is not working.
<Grid x:Name="Grid">
<Grid.RowDefinitions>
<RowDefinition Height="47.5*" />
<RowDefinition Height="auto" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="0.47*" />
</Grid.ColumnDefinitions>
<controls:UCIndicationsOfUse Grid.Row="0" Grid.Column="0"
HorizontalAlignment="Stretch"
VerticalAlignment="Stretch"
Width="auto"
Height="auto"
DataContext="{Binding}" />
<controls:UCPData Grid.Row="1" Grid.Column="0"
HorizontalAlignment="Stretch"
VerticalAlignment="Stretch"
Width="auto"
Height="auto"
DataContext="{Binding}" />
<Expander Grid.Row="0"
Grid.RowSpan="2"
Grid.Column="1"
Width="25"
ExpandDirection="Left"
IsExpanded="False"
HorizontalAlignment="Right">
<Expander.Header>
<TextBlock Text="Settings">
<TextBlock.LayoutTransform>
<RotateTransform Angle="-90"/>
</TextBlock.LayoutTransform>
</TextBlock>
</Expander.Header>
</Expander>

Answer 1

Finally I have added Collapsed and Expanded events to the expander:
<Expander Grid.Row="0"
Grid.RowSpan="2"
Grid.Column="1"
Width="25"
Collapsed="Expander_Collapsed"
Expanded="Expander_Expanded"
ExpandDirection="Left"
IsExpanded="False"
HorizontalAlignment="Right">
<Expander.Header>
<TextBlock Text="Settings">
<TextBlock.LayoutTransform>
<RotateTransform Angle="-90"/>
</TextBlock.LayoutTransform>
</TextBlock>
</Expander.Header>
</Expander>
And then from view code-behind:
private void Expander_Collapsed(object sender, RoutedEventArgs e)
{
ColumnDefinition c = this.Grid.ColumnDefinitions[1];
c.Width = new GridLength(0, GridUnitType.Auto);
this.Grid.ColumnDefinitions.RemoveAt(1);
this.Grid.ColumnDefinitions.Insert(1, c);
}
private void Expander_Expanded(object sender, RoutedEventArgs e)
{
ColumnDefinition c = this.Grid.ColumnDefinitions[1];
c.Width = new GridLength(0.47, GridUnitType.Star);
this.Grid.ColumnDefinitions.RemoveAt(1);
this.Grid.ColumnDefinitions.Insert(1, c);
}
I think this not break MVVM pattern since it is a task for the view.