Three-State CheckBox
<Window x:Class="SimpleStyles.Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="SimpleStyles" Background="#F8F8F8"> <ScrollViewer> <WrapPanel> <!-- CheckBox --> <HeaderedItemsControl Header="CheckBox"> <CheckBox Margin="8">Normal</CheckBox> <CheckBox Margin="8" IsChecked="true">Checked</CheckBox> <CheckBox Margin="8" IsThreeState="true" IsChecked="{x:Null}">Indeterminate</CheckBox> </HeaderedItemsControl> </WrapPanel> </ScrollViewer> </Window>