WPF

#region DependencyProperties
public static readonly DependencyProperty CircleSizeProperty = DependencyProperty.Register(
    "CircleSize", typeof(double), typeof(CircularContextMenu),
    new FrameworkPropertyMetadata(150));

public double CircleSize
{
    get { return (double)GetValue(CircleSizeProperty); }
    set { SetValue(CircleSizeProperty, value); }
}
#endregion DependencyProperties

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using System.Threading;

namespace SilverlightApplication1
{
    public partial class MainPage : UserControl
    {
        delegate void GetData();
        public MainPage()
        {
            GetData gd = new GetData(CallData);
            gd.BeginInvoke(afterCallData, null);
            InitializeComponent();
        }
        void CallData()
        {
            // do something
        }
        void afterCallData( IAsyncResult result)
        {
            // do some thing after completion
        }
    }
}

{System.NotSupportedException: Specified method is not supported.
   at SilverlightApplication1.MainPage.GetData.BeginInvoke(AsyncCallback callback, Object object)
   at SilverlightApplication1.MainPage..ctor()
   at SilverlightApplication1.App.Application_Startup(Object sender, StartupEventArgs e)
   at MS.Internal.CoreInvokeHandler.InvokeEventHandler(Int32 typeIndex, Delegate handlerDelegate, Object sender, Object args)
   at MS.Internal.JoltHelper.FireEvent(IntPtr unmanagedObj, IntPtr unmanagedObjArgs, Int32 argsTypeIndex, Int32 actualArgsTypeIndex, String eventName)}

private void MoveControl(Control control, Window form)
        {
            TransformGroup tGroup = new TransformGroup();

            tGroup.Children.Add(new TranslateTransform(50.0, 50.0));
            control.RenderTransform = tGroup;

            DoubleAnimation dA_X = GenerateDoubleAnimation(-50, 50);
            DoubleAnimation dA_Y = GenerateDoubleAnimation(-50, 50);

            //Get the TranslateTransform for the rectangle (note Children[0], we added TranslateTransform first)
            TranslateTransform tt = (control.RenderTransform as TransformGroup).Children[0] as TranslateTransform;

            //Get the projected bounds of the control

            double dTop = Canvas.GetTop(control) + (double)dA_X.To;
            double dLeft = Canvas.GetLeft(control) + (double)dA_Y.To; 
            double dBottom = dTop + control.Height+ (double)dA_X.To;
            double dRight = dLeft+control.Width + (double)dA_Y.To;


            if (dTop > 0 && dLeft > 0 && dBottom < form.Height && dRight < form.Width)
            {
                tt.BeginAnimation(TranslateTransform.XProperty, dA_X);
                tt.BeginAnimation(TranslateTransform.YProperty, dA_Y);

                GeneralTransform myTrans = control.TransformToAncestor(this);
                Point p1 = myTrans.Transform(new Point(0, 0));

                control.SetValue(Canvas.LeftProperty, p1.X + dA_X.To);
                control.SetValue(Canvas.TopProperty, p1.Y + dA_Y.To);
            }
            else
            {
                MoveControl(control, form);
            }

        }
        DoubleAnimation GenerateDoubleAnimation(int min,int max)
        {
            DoubleAnimation da = new DoubleAnimation();
            
            //da.To = randomNumber.Next(min, max);
            da.To = randomNumber.Next(min, max);
            
            //da.AccelerationRatio = .8;
            //da.DecelerationRatio = .1;
            da.Duration = new Duration(TimeSpan.FromSeconds(.2));

            return da;
        }

<r:RibbonTab Header="Home" >
    <r:RibbonGroup Header="Imaging">
        <r:RibbonButton Label="Archive Images" />
        <r:RibbonButton Label="Our Images" />
    </r:RibbonGroup>
    <r:RibbonTab.Triggers>
        <Trigger Property="IsSelected" Value="True">
            <Setter /> <!-- Show only contentcontrol HomePage -->
        </Trigger>
    </r:RibbonTab.Triggers>
</r:RibbonTab>
...

<ContentControl x:Name="HomePage"  Visibility="Collapsed"/>
<ContentControl x:Name="DocPage" Visibility="Collapsed"/>