WPF将RelativeSource绑定到祖先问题

DataSource

class DataGridItemType
{
    public string weightType;
    public string SourceType;
    private BindingList<DataGridItem> typeCollection = new BindingList<DataGridItem>();
}


BindingList<DataGridItemType> list = new BindingList<DataGridItemType>();

list

Text="{Binding Path=weightType, Mode=TwoWay, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type btm:DataGridItemType}}}

weightType