Read and preset a combobox of color properties

From a tutorial I have the following combobox:

<ComboBox Name="comboBox_waColor" Margin="5,0,5,0" SelectionChanged="comboBox_waColor_SelectionChanged">
        <ComboBox.ItemTemplate>
                <DataTemplate>
                        <StackPanel Orientation="Horizontal">
                                <Rectangle Fill="{Binding Name}" Width="12" Height="12" Margin="0,2,5,2" />
                                <TextBlock Name="PART_ColorName" Text="{Binding Name}" />
                        </StackPanel>
                </DataTemplate>
        </ComboBox.ItemTemplate>
</ComboBox>

I populate it like this:

comboBox_waColor.ItemsSource = typeof(Colors).GetProperties();

I want to save the selected item in a text file to load it to the combobox later again.

What value could I save to use it for that scenario and how should I do it?

SelectedIndex aside I couldn't find one.