如何在wpf中将组合框与组合框结合

I have two Combobox

我有两个Combobox

<ComboBox x:Name="sourceNumber">
    <ComboBoxItem Content="1"/>
    <ComboBoxItem Content="2"/>
    <ComboBoxItem Content="3"/>
    <ComboBoxItem Content="4"/>
    <ComboBoxItem Content="5"/>
<ComboBox