Jak mogę uzyskać kontrolki typu dzieckaComboBox wMyContainer Grid w WPF?

<code><Grid x:Name="MyContainer">                    
    <Label Content="Name"  Name="label1"  />
    <Label Content="State" Name="label2"  />
    <ComboBox Height="23" HorizontalAlignment="Left" Name="comboBox1"/>
    <ComboBox Height="23" HorizontalAlignment="Left" Name="comboBox3" />
    <ComboBox Height="23" HorizontalAlignment="Left" Name="comboBox4" />
</Grid>
</code>

Ta linia daje mi błąd:

<code>var myCombobox = this.MyContainer.Children.GetType(ComboBox);
</code>