====== Source Code DesktopEditionSample RestrictingExtent CS 101103.zip ======


====Program.cs====

<code csharp>
using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;
namespace RestrictingExtent
{
    static class Program
    {
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new TestForm());
        }
    }
}
</code>



====TestForm.cs====

<code csharp>
using System;
using System.Windows.Forms;
using System.Collections.ObjectModel;
using ThinkGeo.MapSuite.Core;
using ThinkGeo.MapSuite.DesktopEdition;

namespace  RestrictingExtent
{
    public partial class TestForm : Form
    {
        RectangleShape restrictedExtentForPanning = new RectangleShape(-127, 51, -65, 21);
        RectangleShape restrictedExtentForZoomOut = null;
        public TestForm()
        {
            InitializeComponent();
        }
        private void TestForm_Load(object sender, EventArgs e)
        {
            //Gets the restricted extent for zooming out based on the restrcited extent for panning
            restrictedExtentForZoomOut = (RectangleShape)restrictedExtentForPanning.CloneDeep();
            restrictedExtentForZoomOut.ScaleUp(80);
            winformsMap1.MapUnit = GeographyUnit.DecimalDegree;
            winformsMap1.CurrentExtent = restrictedExtentForPanning;
            winformsMap1.BackgroundOverlay.BackgroundBrush = new GeoSolidBrush(GeoColor.FromArgb(255, 198, 255, 255));
            //Displays the World Map Kit as a background.
            ThinkGeo.MapSuite.DesktopEdition.WorldMapKitWmsDesktopOverlay worldMapKitDesktopOverlay = new ThinkGeo.MapSuite.DesktopEdition.WorldMapKitWmsDesktopOverlay();
            winformsMap1.Overlays.Add(worldMapKitDesktopOverlay);
            //InMemoryFeatureLayer to show the restricted extent. It is just for display.
            InMemoryFeatureLayer inMemoryFeatureLayer = new InMemoryFeatureLayer();
            inMemoryFeatureLayer.ZoomLevelSet.ZoomLevel01.DefaultAreaStyle = AreaStyles.CreateSimpleAreaStyle(GeoColor.StandardColors.Transparent,
                                        GeoColor.StandardColors.Green, 3);
            inMemoryFeatureLayer.ZoomLevelSet.ZoomLevel01.ApplyUntilZoomLevel = ApplyUntilZoomLevel.Level20;
            inMemoryFeatureLayer.Open();
            inMemoryFeatureLayer.InternalFeatures.Add(new Feature(restrictedExtentForPanning));
            inMemoryFeatureLayer.InternalFeatures.Add(new Feature(restrictedExtentForZoomOut));
            inMemoryFeatureLayer.Close();
            LayerOverlay layerOverlay = new LayerOverlay();
            layerOverlay.Layers.Add(inMemoryFeatureLayer);
            winformsMap1.Overlays.Add(layerOverlay);
            winformsMap1.Refresh();
        }

        private void winformsMap1_CurrentExtentChanging(object sender, CurrentExtentChangingWinformsMapEventArgs e)
        {
            //While changing zoom level. Does not allow zooming out beyond the restricted extent by using the geometric
            //function IsWithin. The new extent has to be within the restricted extent or the zoomin out will be canceled.
            if (e.CurrentExtent.GetBoundingBox().Width != e.NewExtent.GetBoundingBox().Width)
            {
                if (e.NewExtent.IsWithin(restrictedExtentForZoomOut) == false)
                {
                    e.Cancel = true;
                }
            }
            //While panning. It checks for the difference in area of the overlap (GetIntersection) of the current extent and the
            //new extent with the restricted extent for panning. That way, we can be outside the restricted extent for panning after
            //zooming out and still pan to get more within the restricted extent for panning.
            else
            {
                RectangleShape currentIntersection = restrictedExtentForPanning.GetIntersection(e.CurrentExtent);
                RectangleShape newIntersection = restrictedExtentForPanning.GetIntersection(e.NewExtent);
                //Gets the area. Meter is an arbitrary unit.
                double currentArea = currentIntersection.GetArea(GeographyUnit.Meter, AreaUnit.SquareMeters);
                double newArea = newIntersection.GetArea(GeographyUnit.Meter, AreaUnit.SquareMeters);
                if (newArea < currentArea)
                {
                    e.Cancel = true;
                }
            }
        }

        private void winformsMap1_MouseMove(object sender, MouseEventArgs e)
        {
            //Displays the X and Y in screen coordinates.
            statusStrip1.Items["toolStripStatusLabelScreen"].Text = "X:" + e.X + " Y:" + e.Y;
            //Gets the PointShape in world coordinates from screen coordinates.
            PointShape pointShape = ExtentHelper.ToWorldCoordinate(winformsMap1.CurrentExtent, new ScreenPointF(e.X, e.Y), winformsMap1.Width, winformsMap1.Height);
            //Displays world coordinates.
            statusStrip1.Items["toolStripStatusLabelWorld"].Text = "(world) X:" + Math.Round(pointShape.X, 4) + " Y:" + Math.Round(pointShape.Y, 4);
        }
        private void btnClose_Click(object sender, EventArgs e)
        {
            this.Close();
        }

    }
}
</code>