How to associate an inherited nested property value with my virtual machine?

Question

I defined a custom attached property as follows:

public class DataFilter
{
    public static readonly DependencyProperty FilterColumnProperty =
        DependencyProperty.RegisterAttached("FilterColumn", typeof (string), typeof (DataFilter),
                                            new FrameworkPropertyMetadata(string.Empty,
                                                                          FrameworkPropertyMetadataOptions.Inherits));

    public static void SetFilterColumn(UIElement element, string value)
    {
        element.SetValue(FilterColumnProperty, value);
    }

    public static string GetFilterColumn(UIElement element)
    {
        return (string) element.GetValue(FilterColumnProperty);
    }

}

I use it in my XAML as follows:

    <Grid Height="600" Name="grdData" cmds:DataFilter.FilterColumn="datasource_id">
      <Grid.RowDefinitions>
        <RowDefinition></RowDefinition>
        <RowDefinition Height="25"></RowDefinition>
        <RowDefinition Height="50"></RowDefinition>
      </Grid.RowDefinitions>
      <igDP:XamDataGrid Name="xamDataGrid1" VerticalAlignment="Top" DataSource="{Binding Tables[Table1]}" ActiveDataItem="{Binding SelectedItem, Mode=OneWayToSource}" cmds:DataFilter.FilterColumn="{Binding FilterCol, Mode=OneWayToSource">

The goal is to be able to bind the inherited nested value of the cmds: DataFilter.FilterColumn property to the VM FilterCol property. I don’t know how to achieve this. The above / XAML code sets the property of the attached property (strng.Empty) to the default value for the VM property, which is due to the fact that it creates a new instance of the attached property in the child control. I don’t know what XAML syntax to use to bind it to the value set in the Grid (parent) control.

Answer 1

( ), , , , :

DataContext "{t [1]}", , , Binding FilterCol, . {Binding FilterCol, RelativeSource = {RelativeSource AncestorType = {x: }}}  ,

Answer 2

. , DataContext , , , .