original link:
http://www.cnitblog.com/eastperson/archive/2006/10/17/18055.aspx
origin full text:
我在2005上研究了好长时间， 才弄出来个简单的鹰眼，与大家分享，我的设计思路是将后台设置两个map，map1和map2，map1为主地图，map2为鹰眼地图，但是map2没有MapControl，定义一个实现类继承于MapBaseCommand，将map1.Bounds的矩形在map2上转换为System.Drawing.Rectangle，之后将这个Rectangle的左上坐标和width，height传到客户端，应用JS进行客户端绘图，在客户端加入一个Div，Div里放置一个IMG，如下为部分代码：
自定义类：
1
using System;
2using System.Collections;
3using System.Drawing;
4using System.IO;
5using System.Web;
6using System.Web.UI.WebControls;
7using System.Web.UI;
8using MapInfo.Mapping;
9using MapInfo.Data;
10using MapInfo.WebControls;
11
12
13namespace CustomWebTools
14
{
15
/// <summary>
16
/// Info command for InfoWebTool.
17
/// </summary>
18 [Serializable]
19 public class Info : MapInfo.WebControls.MapBaseCommand
20 {
21 /// <summary>
22 /// Key to be used to get the pixel tolerance parameter value from the URL.
23 /// </summary>
24 protected const string PixelToleranceKey = "PixelTolerance";
25 protected const string InfoCommand = "Info";
26
27
28 /// <summary>
29 /// Constructor for Info class
30 /// </summary>
31 public Info()
32 {
33 Name = InfoCommand;
34 }
35
36 /// <summary>
37 /// Override the Execute method in MapBasicCommand class to not save state, because
38 /// for info tool, which does not change map state, so there is no need to save map state.
39 /// </summary>
40 public override void Execute()
41 {
42
43 StateManager sm = StateManager.GetStateManagerFromSession();
44 if (sm == null)
45 {
46 if(StateManager.IsManualState())
47 {
48 throw new NullReferenceException("Cannot find instance of StateManager in the ASP.NET session.");
49 }
50 }
51 ParseContext();
52 if(sm != null)
53 {
54 PrepareStateManagerParamsDictionary(sm);
55 sm.RestoreState();
56 }
57
58 Process();
59 }
60
61 /// <summary>
62 /// method to do the real server side process for info tool.
63 /// </summary>
64 public override void Process()
65 {
66 //get pixel tolerance from url of client side.
67 int pixelTolerance = System.Convert.ToInt32(HttpContext.Current.Request[PixelToleranceKey]);
68
69 MapControlModel model = MapControlModel.GetModelFromSession();
70 model.SetMapSize(MapAlias, MapWidth, MapHeight);
71
72 //extract points from url of client side.
73 System.Drawing.Point[] points = ExtractPoints(DataString);
74
75 //do searching and get results back
76 MultiResultSetFeatureCollection mrfc = RetrieveInfo(points, pixelTolerance);
77
78 IEnumerator resultEnum = mrfc.GetEnumerator();
79
80 //retrieve the selected feature from collection
81 while(resultEnum.MoveNext())
82 {
83 IResultSetFeatureCollection irfc = (IResultSetFeatureCollection)resultEnum.Current;
84 IFeatureEnumerator ftrEnum = irfc.GetFeatureEnumerator();
85
86 while(ftrEnum.MoveNext())
87 {
88 Feature ftr = (Feature)ftrEnum.Current;
89 //create a html table to display feature info and stream back to client side.
90 CreateInfoTable(ftr);
91 irfc.Close();
92 mrfc.Clear();
93 break;
94 }
95 break;
96 }
97 }
98
99 /// <summary>
100 /// Creates html table to hold passed in feature info, and stream back to client.
101 /// </summary>
102 /// <param name="ftr">feature object</param>
103 private void CreateInfoTable(Feature ftr)
104 {
105 //create a table control and populat it with the column name/value(s) from the feature returned and
106 // and the name of the layer where the feature belong
107 System.Web.UI.WebControls.Table infoTable = new System.Web.UI.WebControls.Table();
108 //set table attribute/styles
109 infoTable.CellPadding = 4;
110 infoTable.Font.Name = "Arial";
111 infoTable.Font.Size = new FontUnit(8);
112 infoTable.BorderWidth = 1;
113 //infoTable.BorderStyle = BorderStyle.Outset;
114
115 System.Drawing.Color backColor = Color.Bisque;
116
117 //add the first row, the layer name/value where the selected feature belongs
118 TableRow r = new TableRow();
119 r.BackColor = backColor;
120
121 TableCell c = new TableCell();
122 c.Font.Bold = true;
123 c.ForeColor = Color.Indigo;
124
125 c.Text = "Layer Name";
126 r.Cells.Add(c);
127
128 c = new TableCell();
129
130 //the feature returned is from a resultset table whose name is got from appending _2
131 //to the real table name, so below is to get the real table name.
132 string alias = ftr.Table.Alias;
133 c.Text = alias.Substring(0, alias.Length-2);
134 c.Font.Bold = true;
135 r.Cells.Add(c);
136
137 infoTable.Rows.Add(r);
138
139 foreach(Column col in ftr.Columns)
140 {
141 String upAlias = col.Alias.ToUpper();
142 //don't display obj, MI_Key or MI_Style columns
143 if(upAlias != "OBJ" && upAlias != "MI_STYLE" && upAlias != "MI_KEY")
144 {
145 r = new TableRow();
146 r.BackColor = backColor;
147
148 r.Cells.Clear();
149 c = new TableCell();
150 c.Text = col.Alias;
151 c.Font.Bold = true;
152 c.ForeColor = Color.RoyalBlue;
153
154 r.Cells.Add(c);
155 c = new TableCell();
156 c.Text = ftr[col.Alias].ToString();
157 r.Cells.Add(c);
158 infoTable.Rows.Add(r);
159 }
160 }
161
162 //stream the html table back to client
163 StringWriter sw = new StringWriter();
164 HtmlTextWriter hw = new HtmlTextWriter(sw);
165 infoTable.RenderControl(hw);
166 String strHTML = sw.ToString();
167 HttpContext.Current.Response.Output.Write(strHTML);
168 }
169
170 /// <summary>
171 /// Get a MultiFeatureCollection containing features in all layers falling into the tolerance of the point.
172 /// </summary>
173 /// <param name="points">points array</param>
174 /// <param name="pixelTolerance">pixel tolerance used when searching</param>
175 /// <returns>Returns a MultiResultSetFeatureCollection object</returns>
176 protected MultiResultSetFeatureCollection RetrieveInfo(Point[] points, int pixelTolerance)
177 {
178 if(points.Length != 1)
179 return null;
180
181 MapControlModel model = MapControlModel.GetModelFromSession();
182 //get map object from map model
183 MapInfo.Mapping.Map map = model.GetMapObj(MapAlias);
184
185 if(map == null) return null;
186
187 //creat a layer filter to include normal visible layers for searching
188 IMapLayerFilter layerFilter = MapLayerFilterFactory.FilterForTools(
189 map, MapLayerFilterFactory.FilterByLayerType(LayerType.Normal), MapLayerFilterFactory.FilterVisibleLayers(true),
190 "MapInfo.Tools.MapToolsDefault.SelectLayers", null);
191
192 ITableEnumerator tableEnum = map.Layers.GetTableEnumerator(layerFilter);
193
194 //return if there is no valid layer to search
195 if(tableEnum == null) return null;
196
197 System.Drawing.Point center = points[0];
198
199 //create a SearchInfo with a point and tolerance
200 SearchInfo si = MapInfo.Mapping.SearchInfoFactory.SearchNearest(map, center, pixelTolerance);
201 (si.SearchResultProcessor as ClosestSearchResultProcessor).Options = ClosestSearchOptions.StopAtFirstMatch;
202 //retrieve all columns
203 si.QueryDefinition.Columns = null;
204
205 MapInfo.Geometry.Distance d = MapInfo.Mapping.SearchInfoFactory.ScreenToMapDistance(map, pixelTolerance);
206 (si.SearchResultProcessor as ClosestSearchResultProcessor).DistanceUnit=d.Unit;
207 (si.SearchResultProcessor as ClosestSearchResultProcessor).MaxDistance = d.Value;
208
209
210 //do search
211 MultiResultSetFeatureCollection mrfc = MapInfo.Engine.Session.Current.Catalog.Search(tableEnum, si);
212 return mrfc;
213
214 }
215 }
216
217 /// <summary>
218 /// ZoomValue command to write current zoom value to client for display.
219 /// </summary>
220 [Serializable]
221 public class ZoomValue : MapInfo.WebControls.MapBaseCommand
222 {
223 /// <summary>
224 /// Constructor for ZoomValue class
225 /// </summary>
226 public ZoomValue()
227 {
228 Name = "ZoomValue";
229 }
230
231 /// <summary>
232 /// Override the Execute method in MapBasicCommand class to NOT save state, because
233 /// for this command, which does not change map state, so there is no need to save map state.
234 /// </summary>
235 public override void Execute()
236 {
237
238 StateManager sm = StateManager.GetStateManagerFromSession();
239 if (sm == null)
240 {
241 if(StateManager.IsManualState())
242 {
243 throw new NullReferenceException("Cannot find instance of StateManager in the ASP.NET session.");
244 }
245 }
246 ParseContext();
247 if(sm != null)
248 {
249 PrepareStateManagerParamsDictionary(sm);
250 sm.RestoreState();
251 }
252
253 Process();
254 }
255
256 public override void Process()
257 {
258 MapControlModel model = MapControlModel.GetModelFromSession();
259 //get map object from map model
260 MapInfo.Mapping.Map map = model.GetMapObj(MapAlias);
261 MapInfo.Mapping.Map map2 = model.GetMapObj("Map2");
262 System.Drawing.Rectangle rect;
263 map2.DisplayTransform.ToDisplay(map.Bounds, out rect);
264
265 HttpContext.Current.Response.Output.Write(rect.X);
266 HttpContext.Current.Response.Output.Write(',');
267 HttpContext.Current.Response.Output.Write(rect.Y);
268 HttpContext.Current.Response.Output.Write(',');
269 HttpContext.Current.Response.Output.Write(rect.Width);
270 HttpContext.Current.Response.Output.Write(',');
271 HttpContext.Current.Response.Output.Write(rect.Height);
289 }
290 }
291
}
292
客户端JS代码：
//client info command to control client behavior for info tool.2
function InfoCommand(name, interaction)3
{4
if (arguments.length > 0) {5
this.Init(name, interaction);6
}7
}8
InfoCommand.prototype = new MapCommand();9
InfoCommand.prototype.constructor = InfoCommand;10
InfoCommand.superclass = MapCommand.prototype;11
InfoCommand.prototype.Execute = function()12
{13
this.CreateUrl();14
this.AddParamToUrl("PixelTolerance", this.pixelTolerance);15
//create an XMLHttp obj to send request to server16
var xmlHttp = CreateXMLHttp();17
xmlHttp.open("GET", this.url, false);18
xmlHttp.send(null);19
//get response back20
this.result = xmlHttp.responseText;21
22
var div = FindElement("Info");23
if(div.style.visibility != "visible")24
div.style.visibility = "visible"; 25
//display the response at client html26
div.innerHTML = "<font size=2 face=Arial><b>Selected Feature Info:</b></font><p>" + this.result;27
28
};29
//function to update zoom label30
function getZoomValue()31
{32
//create url to send to server, server command name is "ZoomValue"33
var url = "MapController.ashx?Command=ZoomValue&Ran=" + Math.random();34
var mapImage = document.getElementById("MapControl1_Image"); 35
if (mapImage.mapAlias) 36
url += "&MapAlias=" + mapImage.mapAlias;37
var xmlHttp = CreateXMLHttp();38
xmlHttp.open("GET", url, false);39
xmlHttp.send(null);40
var result = xmlHttp.responseText; 41
var div = FindElement("ZoomValue");42
div.innerHTML = "<font size=2 face=Arial><b>Zoom: <font color=Indigo>" + result + "</font></b></font>";43
44
var arr = new Array();45
arr = result.split(',');46
var left = 1*arr[0];47
var top = 1*arr[1];48
var width = 1*arr[2];49
var height = 1*arr[3];50
if (left < 0) left = 0;51
if (top < 0) top = 0;52
if (width > 232) width = 232;53
if (height > 210) height = 210;54
//alert(left+","+top+","+width+","+height);55
myDrawFunction(left, top, width, height);56
}; 57
58
后台HTML文件代码：
<%@ Page language="c#" Codebehind="WebForm1.aspx.cs" AutoEventWireup="false" Inherits="InfoToolWeb.WebForm1_temp" %>2
<%@ Register TagPrefix="mapinfowebuiwebcontrols" Namespace="MapInfo.WebControls" Assembly="MapInfo.WebControls, Version=4.0.0.362, Culture=neutral, PublicKeyToken=0a9556cc66c0af57" %>3
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >4
<HTML xmlns:v="urn:schemas-microsoft-com:vml">5
<HEAD>6
<title>WebForm1</title>7
<meta content="Microsoft Visual Studio 7.0" name="GENERATOR">8
<meta content="C#" name="CODE_LANGUAGE">9
<meta content="JavaScript" name="vs_defaultClientScript">10
<meta content="http://schemas.microsoft.com/intellisense/ie5" name="vs_targetSchema">11
<style>v\:* { BEHAVIOR: url(#default#VML) }12
</style>13
<script src="wz_jsgraphics.js" type="text/javascript"></script>14
</HEAD>15
<body bgColor="#ffefd5" MS_POSITIONING="GridLayout">16
<form id="Form1" method="post" runat="server">17
<!-- inlcude javascript for info tool here -->18
<script language="javascript" src="CustomCommand.js" type="text/javascript"></script>19
<!-- zoom label used to display current zoom value ->20
<DIV id="ZoomValue" style="DISPLAY: inline; Z-INDEX: 124; LEFT: 120px; WIDTH: 872px; POSITION: absolute; TOP: 88px; HEIGHT: 19px"21
ms_positioning="FlowLayout"><STRONG><FONT face="Arial" size="2">Zoom:</FONT></STRONG></DIV>22
<mapinfowebuiwebcontrols:mapcontrol id="MapControl1" style="Z-INDEX: 101; LEFT: 88px; POSITION: absolute; TOP: 128px"23
runat="server" MapAlias="Map1" Height="600px" Width="600px"></mapinfowebuiwebcontrols:mapcontrol><mapinfowebuiwebcontrols:southnavigationtool id="SouthNavigationTool2" style="Z-INDEX: 102; LEFT: 640px; POSITION: absolute; TOP: 944px"24
runat="server" MapControlID="MapControl1"></mapinfowebuiwebcontrols:southnavigationtool><mapinfowebuiwebcontrols:northnavigationtool id="NorthNavigationTool2" style="Z-INDEX: 104; LEFT: 224px; POSITION: absolute; TOP: 112px"25
runat="server" MapControlID="MapControl1"></mapinfowebuiwebcontrols:northnavigationtool><mapinfowebuiwebcontrols:eastnavigationtool id="EastNavigationTool2" style="Z-INDEX: 105; LEFT: 912px; POSITION: absolute; TOP: 552px"26
runat="server" MapControlID="MapControl1"></mapinfowebuiwebcontrols:eastnavigationtool><mapinfowebuiwebcontrols:westnavigationtool id="WestNavigationTool2" style="Z-INDEX: 106; LEFT: 72px; POSITION: absolute; TOP: 280px"27
runat="server" MapControlID="MapControl1"></mapinfowebuiwebcontrols:westnavigationtool><mapinfowebuiwebcontrols:northeastnavigationtool id="NorthEastNavigationTool1" style="Z-INDEX: 108; LEFT: 840px; POSITION: absolute; TOP: 112px"28
runat="server" MapControlID="MapControl1"></mapinfowebuiwebcontrols:northeastnavigationtool><mapinfowebuiwebcontrols:southwestnavigationtool id="SouthWestNavigationTool1" style="Z-INDEX: 109; LEFT: 64px; POSITION: absolute; TOP: 616px"29
runat="server" MapControlID="MapControl1"></mapinfowebuiwebcontrols:southwestnavigationtool><mapinfowebuiwebcontrols:southeastnavigationtool id="SouthEastNavigationTool1" style="Z-INDEX: 110; LEFT: 952px; POSITION: absolute; TOP: 848px"30
runat="server" MapControlID="MapControl1"></mapinfowebuiwebcontrols:southeastnavigationtool><mapinfowebuiwebcontrols:northwestnavigationtool id="NorthWestNavigationTool1" style="Z-INDEX: 111; LEFT: 72px; POSITION: absolute; TOP: 112px"31
runat="server" MapControlID="MapControl1"></mapinfowebuiwebcontrols:northwestnavigationtool><mapinfowebuiwebcontrols:zoombartool id="ZoomBarTool1" style="Z-INDEX: 112; LEFT: 24px; POSITION: absolute; TOP: 216px"32
runat="server" Height="8px" MapControlID="MapControl1" ZoomLevel="12500"></mapinfowebuiwebcontrols:zoombartool><mapinfowebuiwebcontrols:zoombartool id="ZoomBarTool2" style="Z-INDEX: 113; LEFT: 24px; POSITION: absolute; TOP: 240px"33
runat="server" Height="8px" MapControlID="MapControl1" ZoomLevel="6500"></mapinfowebuiwebcontrols:zoombartool><mapinfowebuiwebcontrols:zoombartool id="ZoomBarTool3" style="Z-INDEX: 114; LEFT: 24px; POSITION: absolute; TOP: 264px"34
runat="server" Height="8px" MapControlID="MapControl1" ZoomLevel="3550"></mapinfowebuiwebcontrols:zoombartool><mapinfowebuiwebcontrols:zoombartool id="ZoomBarTool4" style="Z-INDEX: 115; LEFT: 24px; POSITION: absolute; TOP: 288px"35
runat="server" MapControlID="MapControl1" ZoomLevel="1500"></mapinfowebuiwebcontrols:zoombartool><mapinfowebuiwebcontrols:zoombartool id="ZoomBarTool5" style="Z-INDEX: 116; LEFT: 24px; POSITION: absolute; TOP: 312px"36
runat="server" MapControlID="MapControl1" ZoomLevel="500"></mapinfowebuiwebcontrols:zoombartool><asp:image id="Image1" style="Z-INDEX: 117; LEFT: 32px; POSITION: absolute; TOP: 336px" runat="server"37
ImageUrl="/MapXTremeWebResources 6_5/ZoomInToolControlActive.gif"></asp:image><asp:image id="Image2" style="Z-INDEX: 118; LEFT: 32px; POSITION: absolute; TOP: 192px" runat="server"38
ImageUrl="/MapXTremeWebResources 6_5/ZoomOutToolControlActive.gif"></asp:image>39
<div id="Info" style="Z-INDEX: 119; LEFT: 712px; VISIBILITY: hidden; POSITION: absolute; TOP: 16px">Div element 40
to display selected feature information in html table.</div>41
<mapinfowebuiwebcontrols:pantool id="PanTool1" style="Z-INDEX: 120; LEFT: 984px; POSITION: absolute; TOP: 464px"42
runat="server" MapControlID="MapControl1" ClientCommand="MapCommand"></mapinfowebuiwebcontrols:pantool><mapinfowebuiwebcontrols:zoomintool id="ZoomInTool1" style="Z-INDEX: 121; LEFT: 904px; POSITION: absolute; TOP: 464px"43
runat="server" MapControlID="MapControl1"></mapinfowebuiwebcontrols:zoomintool><mapinfowebuiwebcontrols:zoomouttool id="ZoomOutTool1" style="Z-INDEX: 122; LEFT: 944px; POSITION: absolute; TOP: 464px"44
runat="server" MapControlID="MapControl1"></mapinfowebuiwebcontrols:zoomouttool><mapinfowebuiwebcontrols:centertool id="CenterTool1" style="Z-INDEX: 123; LEFT: 1024px; POSITION: absolute; TOP: 464px"45
runat="server" MapControlID="MapControl1"></mapinfowebuiwebcontrols:centertool><mapinfowebuiwebcontrols:pointselectiontool id="InfoWebTool1" style="Z-INDEX: 125; LEFT: 1072px; POSITION: absolute; TOP: 464px"46
runat="server" MapControlID="MapControl1" ClientInteraction="ClickInteraction" ActiveImageUrl="/MapXtremeWebResources 6_5/InfoToolControlActive.gif" InactiveImageUrl="/MapXtremeWebResources 6_5/InfoToolControlInActive.gif"47
CursorImageUrl="/MapXtremeWebResources 6_5/MapInfoWebInfo.cur" Command="Info" ClientCommand="InfoCommand"></mapinfowebuiwebcontrols:pointselectiontool><asp:label id="Label1" style="Z-INDEX: 107; LEFT: 72px; POSITION: absolute; TOP: 16px" runat="server"48
Height="48px" Width="712px" Font-Size="X-Large" ForeColor="Navy" BorderColor="MediumTurquoise">InfoTool Web Sample </asp:label><asp:textbox id="TextBox1" style="Z-INDEX: 103; LEFT: 64px; POSITION: absolute; TOP: 64px" runat="server"49
Height="8px" Width="806px" BackColor="DarkBlue"></asp:textbox><mapinfowebuiwebcontrols:rectangleselectiontool id="RectangleSelectionTool1" style="Z-INDEX: 126; LEFT: 1104px; POSITION: absolute; TOP: 464px"50
runat="server" MapControlID="MapControl1" Command="RectangleSelection" ClientCommand="MapCommand" Active="True"></mapinfowebuiwebcontrols:rectangleselectiontool>51
<div id="myCanvas" style="LEFT:896px;WIDTH:230px;POSITION:absolute;TOP:120px;HEIGHT:230px"><IMG src="file:///C:\Program Files\MapInfo\MapXtreme\6.5\Samples\Web\Features\InfoToolWeb\cs\eyemap.GIF"52
height="230" width="230"></div>53
<script src="drawfunction.js" type="text/javascript"></script>54
<INPUT style="Z-INDEX: 128; LEFT: 896px; POSITION: absolute; TOP: 416px" type="button"55
value="Button" onclick="myDrawFunction()">56
<script language="javascript" type="text/javascript">57
//first time when page loads, at this point, maybe the image is already loaded, so58
//alway call getZoomValue when the page loads first time.59
getZoomValue();60
61
//hook up map image onload event with getZoomValue method.62
var mapimage = document.getElementById("MapControl1_Image"); 63
mapimage.onload = getZoomValue; 64
</script>65
</form>66
</body>67
</HTML>68
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