So I have a `DataGridComboBoxColumn` `ColCID` whose value depends on another cell of the row `ColSID` (see below code). I tried to implement it with an IValueConverter but I get this error:

> 
> Cannot find governing FrameworkElement or FrameworkContentElement for target element. BindingExpression:(no path); DataItem=null; target element is 'DataGridComboBoxColumn' (HashCode=18018639); target property is 'ItemsSource' (type 'IEnumerable')
> 
> 
> 

XAML:

```
<DataGridComboBoxColumn x:Name="ColSID" Header="Guild"
                        SelectedValueBinding="{Binding SID, Mode=TwoWay}"
                        SelectedValuePath="SID"
                        DisplayMemberPath="Name" />
<DataGridComboBoxColumn x:Name="ColCID" Header="Channel"
                        ItemsSource="{ Binding ElementName=ColSID, Converter={StaticResource ChannelConverter} }"
                        SelectedValueBinding="{Binding CID, Mode=TwoWay}"
                        SelectedValuePath="CID"
                        DisplayMemberPath="Name" />

```

Converter:

```
public class ChannelConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        Guild guild = SenderView.Guilds.Find(g => g.SID == value.ToString());
        if (guild != null) return guild.Channels;
        return null;
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}
...
public class Guild
{
    public class Channel
    {
        public string CID { get; set; }
        public string Name { get; set; }
    }
    public string SID { get; set; }
    public string Name { get; set; }
    public List<Channel> Channels { get; set; }
}

```