In this article I am going to explain WPF
Expander control. An Expander control is used to wrap or expand the content of items. You may have noticed some websites provide functionalty to close and open some controls. This can be achieved in WPF using the Expander control.
Below is the XAML Code:
<Window x:Class="WpfApplication1.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Window1" Height="300" Width="300">
<Grid>
<Expander Header="Select Country">
<StackPanel Margin="10,4,0,0">
<CheckBox Margin="4" Content="India" />
<CheckBox Margin="4" Content="USA" />
<CheckBox Margin="4" Content="UK" />
</StackPanel>
</Expander>
</Grid>
</Window>

Image 1.

Image 2.