//放大的代码：

private void MapZoomIn(NameValueCollection queryString)

    {

        SharpMap.Map map = Session["map"] as SharpMap.Map;

        PointF pointFLeftBottom = new PointF(float.Parse(queryString["Left"]), float.Parse(queryString["Bottom"]));

        PointF pointFRightTop = new PointF(float.Parse(queryString["Right"]), float.Parse(queryString["Top"]));

        SharpMap.Geometries.BoundingBox zoomToBoundingBox = new SharpMap.Geometries.BoundingBox(map.ImageToWorld(pointFLeftBottom), map.ImageToWorld(pointFRightTop));

        map.ZoomToBox(zoomToBoundingBox);

        Session.Remove("map");

        Session["map"] = map;

    }

//缩小的代码：

    private void MapZoomOut(NameValueCollection queryString)

    {

        SharpMap.Map map = Session["map"] as SharpMap.Map;

        PointF pointFLeftBottom = new PointF(float.Parse(queryString["Left"]), float.Parse(queryString["Bottom"]));

        PointF pointFRightTop = new PointF(float.Parse(queryString["Right"]), float.Parse(queryString["Top"]));

        SharpMap.Geometries.BoundingBox boundingBox = new SharpMap.Geometries.BoundingBox(map.ImageToWorld(pointFLeftBottom), map.ImageToWorld(pointFRightTop));

        SharpMap.Geometries.Point mapCenterPoint = boundingBox.GetCentroid();       

        double ratio = 0.0;

        double ratioX=boundingBox.Width / map.Envelope.Width;

        double ratioY=boundingBox.Height / map.Envelope.Height;

        if (ratioX > ratioY)

        {

            ratio = ratioX;

        }

        else

        {

            ratio = ratioY;

        }

        double semiWidth = map.Envelope.Width / ratio / ;

        double semiHeight = map.Envelope.Height / ratio / ;

        SharpMap.Geometries.BoundingBox zoomToBoundingBox = new SharpMap.Geometries.BoundingBox(mapCenterPoint.X - semiWidth, mapCenterPoint.Y - semiHeight, mapCenterPoint.X + semiWidth, mapCenterPoint.Y + semiHeight);

        map.ZoomToBox(zoomToBoundingBox);

        Session.Remove("map");

        Session["map"] = map;

    }

//平移的代码：

    private void MapPan(NameValueCollection queryString)

    {

        SharpMap.Map map = Session["map"] as SharpMap.Map;

        PointF pointFFirst = new PointF(float.Parse(queryString["FirstX"]), float.Parse(queryString["FirstY"]));

        PointF pointFSecond = new PointF(float.Parse(queryString["SecondX"]), float.Parse(queryString["SecondY"]));

        SharpMap.Geometries.Point firstPoint = map.ImageToWorld(pointFFirst);

        SharpMap.Geometries.Point secondPoint = map.ImageToWorld(pointFSecond);

        SharpMap.Geometries.Point mapCenterPoint = map.Center;

        SharpMap.Geometries.Point mapNewCenterPoint = new SharpMap.Geometries.Point(mapCenterPoint.X + firstPoint.X - secondPoint.X, mapCenterPoint.Y + firstPoint.Y - secondPoint.Y);

        map.Center = mapNewCenterPoint;

        Session.Remove("map");

        Session["map"] = map;

    }

//全图显示的代码：

    private void MapFullExtent(NameValueCollection queryString)

    {

        SharpMap.Map map = Session["map"] as SharpMap.Map;

        map.ZoomToExtents();

        Session.Remove("map");

        Session["map"] = map;

    }

//空间查询的代码：

private void MapQuery(NameValueCollection queryString)

    {

        SharpMap.Map map = Session["map"] as SharpMap.Map;

        PointF pointFLeftBottom = new PointF(float.Parse(queryString["Left"]), float.Parse(queryString["Bottom"]));

        PointF pointFRightTop = new PointF(float.Parse(queryString["Right"]), float.Parse(queryString["Top"]));

        SharpMap.Geometries.BoundingBox boundingBox = new SharpMap.Geometries.BoundingBox(map.ImageToWorld(pointFLeftBottom), map.ImageToWorld(pointFRightTop));

        SharpMap.Data.FeatureDataSet featureDataSet = new SharpMap.Data.FeatureDataSet();

        ILayer pLayer = map.GetLayerByName(queryString["LayerName"]);

        SharpMap.Layers.VectorLayer vectorLayer = pLayer as SharpMap.Layers.VectorLayer;

        vectorLayer.DataSource.ExecuteIntersectionQuery(boundingBox, featureDataSet);

        if (featureDataSet.Tables.Count > ) //得到了结果

        {

            //增加点击选择的对象到selection图层

            //这样就新增了一个图层，因此渲染该副地图则显示选中对象

            SharpMap.Layers.VectorLayer layerSelected = new SharpMap.Layers.VectorLayer("Selection");

            layerSelected.DataSource = new SharpMap.Data.Providers.GeometryProvider(featureDataSet.Tables[]);

            layerSelected.Style.Fill = new System.Drawing.SolidBrush(System.Drawing.Color.Yellow);

            map.Layers.Add(layerSelected);

        }

        Session.Remove("map");

        Session["map"] = map;

    }

//长度测量的代码：

private void MapMeasurePolyline(NameValueCollection queryString, out string responseXML)

    {

        SharpMap.Map map = Session["map"] as SharpMap.Map;

        string pointsCoordinate = queryString["PointsCoordinate"];

        string[] pointCoordinatePair = pointsCoordinate.Split(',');

        SharpMap.Geometries.LineString lineStringMeasure = new SharpMap.Geometries.LineString();

        for (int i = ; i < pointCoordinatePair.Length / ; i++)

        {

            PointF pointF=new PointF(Convert.ToSingle(pointCoordinatePair[i*]),Convert.ToSingle(pointCoordinatePair[i*+]));

            SharpMap.Geometries.Point point = map.ImageToWorld(pointF);

            lineStringMeasure.Vertices.Add(point);

        }

        StringBuilder resultsXML = new StringBuilder("");

        resultsXML.Append("<?xml version=\"1.0\" encoding=\"utf-8\"?>");

        resultsXML.Append("<map>");

        resultsXML.Append("<measure>");

        resultsXML.Append("<长度>");

        resultsXML.Append("<![CDATA[");

        resultsXML.Append(lineStringMeasure.Length.ToString());

        resultsXML.Append("]]>");

        resultsXML.Append("</长度>");

        resultsXML.Append("</measure>");

        resultsXML.Append("</map>");

        responseXML = resultsXML.ToString();

    }