Is it possible to get dynamic columns on wpf datagrid in mvvm pattern?

Question

Im developing a product in wpf (mvvm pattern). I have a scenario in which i have spent more than a week for no good result. Pls help me if you can... Here is the scenario, a

Answer 1

I would like to extend the previous example (answer) the ability to subscribe and unsubscribe on event CollectionChanged.

Behavior (add reference on System.Windows.Interactivity):

 public class ColumnsBindingBehaviour : Behavior
{
    public ObservableCollection Columns
    {
        get { return (ObservableCollection) base.GetValue(ColumnsProperty); }
        set { base.SetValue(ColumnsProperty, value); }
    }

    public static readonly DependencyProperty ColumnsProperty = DependencyProperty.Register("Columns",
        typeof(ObservableCollection), typeof(ColumnsBindingBehaviour),
            new PropertyMetadata(OnDataGridColumnsPropertyChanged));

    private static void OnDataGridColumnsPropertyChanged(DependencyObject source, DependencyPropertyChangedEventArgs e)
    {
        var context = source as ColumnsBindingBehaviour;

        var oldItems = e.OldValue as ObservableCollection;

        if (oldItems != null)
        {
            foreach (var one in oldItems)
                context._datagridColumns.Remove(one);

            oldItems.CollectionChanged -= context.collectionChanged;
        }

        var newItems = e.NewValue as ObservableCollection;

        if (newItems != null)
        {
            foreach (var one in newItems)
                context._datagridColumns.Add(one);

            newItems.CollectionChanged += context.collectionChanged;
        }
    }

    private ObservableCollection _datagridColumns;

    protected override void OnAttached()
    {
        base.OnAttached();

        this._datagridColumns = AssociatedObject.Columns;
    }


    private void collectionChanged(object sender, NotifyCollectionChangedEventArgs e)
    {
        switch (e.Action)
        {
            case NotifyCollectionChangedAction.Add:
                if (e.NewItems != null)
                    foreach (DataGridColumn one in e.NewItems)
                        _datagridColumns.Add(one);
                break;

            case NotifyCollectionChangedAction.Remove:
                if (e.OldItems != null)
                    foreach (DataGridColumn one in e.OldItems)
                        _datagridColumns.Remove(one);
                break;

            case NotifyCollectionChangedAction.Move:
                _datagridColumns.Move(e.OldStartingIndex, e.NewStartingIndex);
                break;

            case NotifyCollectionChangedAction.Reset:
                _datagridColumns.Clear();
                if (e.NewItems != null)
                    foreach (DataGridColumn one in e.NewItems)
                        _datagridColumns.Add(one);
                break;
        }
    }
}

View:

ViewModel:

     private ObservableCollection _dataGridColumns;
     public ObservableCollection DataGridColumns
     {
         get
         {
             if (_dataGridColumns == null)
                 _dataGridColumns = new ObservableCollection()
                 {
                     new DataGridTextColumn()
                     {
                         Header = "Column1"
                     }
                 };

             return _dataGridColumns;
         }
         set
         {
             _dataGridColumns = value;
             OnPropertyChanged("DataGridColumns");
         }
     }