Bing Maps in SharePoint 2010 Web Part

using System;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using VisualWebPartProject1.GeocodeService;
using VisualWebPartProject1.ImageryService;
using VisualWebPartProject1.ControlTemplates;

namespace VisualWebPartProject1.BingMapsWebPart
{
    public partial class BingMapsWebPartUserControl : UserControl
    {
        const string longititudeKey = "longititude";
        const string latitudeKey = "latitude";
        const string zoomKey = "zoom";

        double longititude;
        double latitude;
        int zoom = 15;

        protected void Page_Load(object sender, EventArgs e)
        {
            lblError.Visible = true;
            if (ViewState[longititudeKey] != null)
            {
                longititude = (double)ViewState[longititudeKey];
                latitude = (double)ViewState[latitudeKey];
                zoom = (int)ViewState[zoomKey];
            }

            //if (!Page.IsPostBack)
            {
                ((BingMapNav)BingMapNav1).ZoomOutButtonClick += new BingMapNav.ButtonClickDelegate(ZoomOut);
                ((BingMapNav)BingMapNav1).ZoomInButtonClick += new BingMapNav.ButtonClickDelegate(ZoomIn);
                ((BingMapNav)BingMapNav1).ScrollDownButtonClick += new BingMapNav.ButtonClickDelegate(ScrollDown);
                ((BingMapNav)BingMapNav1).ScrollLeftButtonClick += new BingMapNav.ButtonClickDelegate(ScrollLeft);
                ((BingMapNav)BingMapNav1).ScrollRightButtonClick += new BingMapNav.ButtonClickDelegate(ScrollRight);
                ((BingMapNav)BingMapNav1).ScrollUpButtonClick += new BingMapNav.ButtonClickDelegate(ScrollUp);
            }
        }

        protected void Page_PreRender(object sender, EventArgs e)
        {
            ViewState[longititudeKey] = longititude;
            ViewState[latitudeKey] = latitude;
            ViewState[zoomKey] = zoom;
        }

        protected void ZoomOut()
        { 
            zoom -=2;
            lblError.Text = "New Zoom " + zoom;
            mapImage.ImageUrl = BingMapHelper.GetImagery(latitude, longititude, zoom);
        }

        protected void ZoomIn()
        {
            zoom += 2;
            lblError.Text = "New Zoom " + zoom;
            mapImage.ImageUrl = BingMapHelper.GetImagery(latitude, longititude, zoom);
        }

        protected void ScrollDown()
        {
            latitude -= 0.2;
            lblError.Text = "New latitude " + latitude;
            mapImage.ImageUrl = BingMapHelper.GetImagery(latitude, longititude, zoom);
        }

        protected void ScrollLeft()
        {
            longititude -= 0.2;
            lblError.Text = "New longititude " + longititude;
            mapImage.ImageUrl = BingMapHelper.GetImagery(latitude, longititude, zoom);
        }

        protected void ScrollRight()
        {
            longititude += 0.2;
            lblError.Text = "New longititude " + longititude;
            mapImage.ImageUrl = BingMapHelper.GetImagery(latitude, longititude, zoom);
        }

        protected void ScrollUp()
        {
            latitude += 0.2;
            lblError.Text = "New latitude " + latitude;
            mapImage.ImageUrl = BingMapHelper.GetImagery(latitude, longititude, zoom);
        }


        protected void btnGetMap_Click(object sender, EventArgs e)
        {
            lblError.Visible = false;
            try
            {
                //Get map

                GeocodeResponse resp = BingMapHelper.GeocodeAddressGeocodeResponse(txtAddress.Text);
                latitude = resp.Results[0].Locations[0].Latitude;
                longititude = resp.Results[0].Locations[0].Longitude;

                //Get URI and set image
                mapImage.ImageUrl = BingMapHelper.GetImagery(latitude, longititude, zoom);

                //Show image
                mapImage.Visible = true;
            }
            catch (Exception ex)
            {
                lblError.Visible = true;
                lblError.Text = ex.Message + "<BR>" + ex.StackTrace;
            }
        }
    }
}