Hi bouhmid86,

A sample approach to achieve this could be the following.

XAML:
        <igMap:XamMap x:Name="map1" Loaded="map1_Loaded">
            <igMap:XamMap.Layers>
                <igMap:MapLayer x:Name="statesLayer">
                    <igMap:MapLayer.Reader>
                        <igMap:ShapeFileReader Uri="Shapefiles/usa/usa_st" DataMapping="Name=STATE_NAME; Value=POP1997; Caption=STATE_NAME"/>
                    </igMap:MapLayer.Reader>
                </igMap:MapLayer>
            </igMap:XamMap.Layers>
        </igMap:XamMap>

CB:
        private void map1_Loaded(object sender, RoutedEventArgs e)
        {
            ZoomMapToRegion(3);
        }

        public void ZoomMapToRegion(double zoom)
        {
            DispatcherTimer timer = new DispatcherTimer() { Interval = TimeSpan.FromSeconds(1.0) };

            timer.Tick += (o, e) =>
            {
                map1.WindowZoom = zoom;
                ((DispatcherTimer)o).Stop();
            };

            timer.Start();
        }

Hope that helps,
Milana Zhileva