Why not dispose of RadPanes? Memory leak issue.

[Greg]

Through forum searches I've realized that you never actually dispose of a Pane, rather make IsHidden to True upon "close," either from a floating ToolWindow or when it's in its docked state.

This is very aggravating, and since I realize this is probably not something you'll change, I'm wondering why did you decide this was appropriate and how can I as a developer handle the resulting memory leaks? How am I to handle View/Viewmodel disposal when a user closes a Pane if the pane continues to exist with a strong reference via its Content and/or DataContext?

If there was even a proper event or argument that would signify a close, that would be fine - I could kill the view/vm myself. But, neither VisibilityChanged nor PaneStateChanged fire on close, and I don't see anything during Pane_Unloaded that would say for certain the pane is closing and not doing something like changing docking states (when you undock or re-dock a pane, its IsHidden is false during the transition, so that doesn't help at all).

TL;DR: Any thoughts on how to know when a pane is closed?

[Miroslav Nedyalkov]

Hello Greg,

You could use the PreviewClose and Close events of the Docking control. We decided to put the events to the Docking control as it is easer to handle events at the element which is not moved/changed during the application lifetime.

We decided to not remove the panes by default, because it is easier to remove them if you need to instead of inserting them back if you want to leave them in the Docking control. We are planning to add property to the RadDocking control for this.

Here is an example how to achieve this:

public class DockingExtensions
{
    public static bool GetRemovePanesWhenClosed(DependencyObject obj)
    {
        return (bool)obj.GetValue(RemovePanesWhenClosedProperty);
    }

    public static void SetRemovePanesWhenClosed(DependencyObject obj, bool value)
    {
        obj.SetValue(RemovePanesWhenClosedProperty, value);
    }

    public static readonly DependencyProperty RemovePanesWhenClosedProperty =
        DependencyProperty.RegisterAttached("RemovePanesWhenClosed", typeof(bool), typeof(DockingExtensions), new PropertyMetadata(false, OnRemovePanesWhenClosedPropertyChanged));

    private static void OnRemovePanesWhenClosedPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var newValue = (bool)e.NewValue;
        var dock = d as RadDocking;

        if (dock != null)
        {
            if (newValue)
            {
                dock.PreviewClose += dock_PreviewClose;
            }
            else
            {
                dock.PreviewClose -= dock_PreviewClose;
            }
        }
    }

    private static void dock_PreviewClose(object sender, Telerik.Windows.Controls.Docking.StateChangeEventArgs e)
    {
        foreach (var pane in e.Panes)
            pane.RemoveFromParent();

        e.Handled = true;
    }
}

Having this attached property you just need to set it to the Docking control:

<telerik:RadDocking local:DockingExtensions.RemovePanesWhenClosed="True">

Hope this helps.

Kind regards,
Miroslav Nedyalkov
the Telerik team

[Cody]

Has this been added to the docking control yet?  I am using version 2011.2.920.1040.

[Miroslav Nedyalkov]

Hi Cody,

This feature is not added to the Docking control yet.

Regards,
Miroslav Nedyalkov
the Telerik team

[Adiel]

We have issues with this behavior. 
Any news on removing RadPane? 

[Kalin]

Hi Meir,

If you'd need to dispose a Pane you would have to manually call its RemoveFromParent method - this behavior is not implemented in control. However you can easily do that by simply hook to the PreviewClose event of the control and call the RemoveFromParent method of the Pane. However as this thread is really old - if you face any particular issue with the control, I'll kindly ask you to open a support ticket with detailed explanation of the issue and sample project attached if possible.

Hope this helps.

Regards,
Kalin
Telerik