RadGridView MVVM Bind Row Expanded

[Kevin]

I have a WPF /MVVM application. I need to put  2 buttons, Expand All and Collapse All above the grid. I need an example of binding each row's expanded property to a view model.

Thank you

[Yoan]

Hi Kevin,

Generally, you can use GridView's ExpandAllHierarchyItems and CollapseAllHierarchyItems methods. As for binding of GridViewRow's IsExpanded - you can bind it to a property of your business object by subscribing to GridView's RowLoaded event. It will be something similar to this:

private void clubsGrid_RowLoaded(object sender, Telerik.Windows.Controls.GridView.RowLoadedEventArgs e)
        {
            var row = e.Row as GridViewRow;

            if (row == null)
                return;

            var selectedBinding = new Binding("IsExpanded");
            selectedBinding.Source = row.Item;
            selectedBinding.Mode = BindingMode.TwoWay;

            row.SetBinding(GridViewRow.IsExpandedProperty, selectedBinding);
        }

Regards,
Yoan
Telerik

[Kevin]

Subscribing to an event means I now have data code in the code behind for the view, which is not MVVM. Is there not a row template with an IsExpanded property that I can bind to?

[Yoan]

Hi Kevin,

If you want to have your code-behind clean, the way to go is with an Attached behavior. Here you can find information about it. You will write the attached behavior only once. This attached behavior will attach to the event and will set the binding. Then you can enable this attached behavior on a RadGridView. Here is a very nice article about event handling with attached behaviors. You have the code in one place only. All you will need to do is something like this:

<RadGridView EnableMyAttachedBehavior="True"/> and then let the attached behavior kick in and do its job. 


Regards,
Yoan
Telerik