[求助][讨论]mapxtreme2005 web 划线问题

<P>谁能给看一下这个在webGis上画线的代码，每当我画完双击后地图消失</P>
<P>    [Serializable]<BR>    public class Line : MapInfo.WebControls.MapBaseCommand<BR>    {<BR>        public Line()<BR>        {<BR>            Name = "Line";<BR>        }</P>
<P>        public override void Process()<BR>        {<BR>            MapControlModel model = MapControlModel.GetModelFromSession();<BR>            model.SetMapSize(MapAlias, MapWidth, MapHeight);</P>
<P>            //extract points from url of client side.<BR>            System.Drawing.Point[] points = ExtractPoints(DataString);</P>
<P>            MapInfo.Mapping.Map map = model.GetMapObj(MapAlias);<BR>            MapInfo.Mapping.FeatureLayer workLayer = (MapInfo.Mapping.FeatureLayer)map.Layers["行政区"];<BR>            MapInfo.Data.Table tblTemp = MapInfo.Engine.Session.Current.Catalog.GetTable("行政区");<BR>            <BR>            for (int i = 0; i <points.Length-1; i++)<BR>            {<BR>                DPoint startPoint;<BR>                DPoint endPoint;<BR>                map.DisplayTransform.FromDisplay(points, out startPoint);<BR>                map.DisplayTransform.FromDisplay(points[i + 1], out endPoint);<BR>           </P>
<P>                FeatureGeometry lfg = MultiCurve.CreateLine(workLayer.CoordSys, startPoint, endPoint);<BR>                MapInfo.Styles.SimpleLineStyle lstyle = new MapInfo.Styles.SimpleLineStyle(<BR>                    new MapInfo.Styles.LineWidth(3, MapInfo.Styles.LineWidthUnit.Pixel), 2, System.Drawing.Color.OrangeRed);<BR>                MapInfo.Styles.CompositeStyle cstyle = new MapInfo.Styles.CompositeStyle(lstyle);<BR>                MapInfo.Data.Feature lft = new MapInfo.Data.Feature(tblTemp.TableInfo.Columns);<BR>                lft.Geometry = lfg;<BR>                lft.Style = cstyle;<BR>                lft["index"] = i;<BR>                workLayer.Table.InsertFeature(lft);<BR>            }</P>
<P>            System.IO.MemoryStream ms = model.GetMap(MapAlias, MapWidth, MapHeight, ExportFormat);<BR>            StreamImageToClient(ms);</P>
<P>        }</P>
<P><BR>    }<BR>在页面上拖放一个自定义控件WebTool，对其样式进行设置，有几个属性需要选择：</P>
<P>ID:LineTool1</P>
<P>ClientCommand:MapCommand</P>
<P>ClientInteraction:PolylineInteraction</P>
<P>Command:Line</P>

<P>在页面加载中添加Line的命令注册。代码如下：</P>

<DIV class=cnblogs_code><!--<br /><br />Code highlighting produced by Actipro CodeHighlighter (freeware)<br />http://www.CodeHighlighter.com/<br /><br />--><IMG src="http://www.cnblogs.com/Images/OutliningIndicators/None.gif" align=top>if (Session.IsNewSession)<BR>{<BR><IMG src="http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif" align=top>MapControlModel model = MapControlModel.SetDefaultModelInSession();<BR><IMG src="http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif" align=top>model.Commands.Add(new Line());<BR><IMG src="http://www.cnblogs.com/Images/OutliningIndicators/ExpandedBlockEnd.gif" align=top>}</DIV>