Wpf DataGrid : changing the XML field binding at runtime

I am developing a WPF User Control for displaying portions of XML files. I'm trying to make the User Control flexible, so that I can assign the column headings and field data bindings from the outside of the control.

I've found that I can easily change the column headings, but while the following code seemed to have promise, SertMemberPath doesn't change the field binding

    public void ChangeColumnDefinitions ( List<XmlGridColumnDefinition> columns )
    {
        int columnnum = 0;
        foreach ( XmlGridColumnDefinition column in columns )
        {
            this.datagrid.Columns[columnnum].Header = column.Heading;
            this.datagrid.Columns[columnnum].SortMemberPath = string.Format ( "Element[{0}].Value", column.FieldName );
            ++columnnum;
        }
    }

From stackoverflow

• Sorry to not have found this in my first search.

  After looking around more I found this question and answer by @Generic_Error on SO. I modified his code slightly and here is what I came up with this which I can customize further.

      public void ChangeColumnDefinitions ( IEnumerable<XmlGridColumnDefinition> columns )
      {
          this.datagrid.Columns.Clear ();
          foreach ( var column in columns )
          {
              DataGridTextColumn coldef = new DataGridTextColumn
                  {
                      Header = column.Heading,
                      Binding = new Binding ( string.Format ( "Element[{0}].Value", column.FieldName ) )
                  };
              this.datagrid.Columns.Add ( coldef );
          }
      }