C#+SharpMap的相关代码

//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 / 2;
        double semiHeight = map.Envelope.Height / ratio / 2;
        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 > 0) //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[0]);
            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 = 0; i < pointCoordinatePair.Length / 2; i++)
        {            
            PointF pointF=new PointF(Convert.ToSingle(pointCoordinatePair[i*2]),Convert.ToSingle(pointCoordinatePair[i*2+1]));
            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();       
    }