mapxtreme2004经典代码之一：添加几何对象

In MXT, geometry & style are object model.
在mxt中，几何实体和样式都是对象模型。

The follow example code demonstrate how to create a geometry , add it to map to display it:
下面的代码演示了怎样生成一个几何对象（Point），然后＋到地图控件上去显示。

The code is not difficult, but I put is here only because it covers many concepts like CoordSys(&CoordSysFactory：Design Patter Concepte), TableInfo(TableInfoMemTable), Table(Column,GeometryColumn,MI Ado.net data provider MIConnection, MICommand), Feature(FeatureGeometry)
代码本身并不难，我在这里放置这段代码的原因是因为它涉及到很多概念：坐标系（坐标系工厂：设计模式概念），表格元数据:表格信息（内存表格），表格（列，集合列，MapInfo数据提供者，数据连接，命令）图元（几何图元）

I hope u can have a deeper understanting about i
希望你能有一个深刻的理解。
The code is without any comment, I think u r more clever than me.
代码没有注释，因为我认为你比我更聪明，

1 private void button1_Click(object sender, System.EventArgs e)
2
4 CoordSysFactory csf = new CoordSysFactory();
5 CoordSys coordsys = csf.CreateCoordSys("mapinfo:coordsys 1,104");
6 double x = 10,y=20;
7
8 TableInfoMemTable timt = new MapInfo.Data.TableInfoMemTable("mem");
9
10
11
12 GeometryColumn gc = new MapInfo.Data.GeometryColumn(coordsys);
13 gc.Alias = "Obj";
14 gc.DataType = MIDbType.FeatureGeometry;
15 timt.Columns.Add(gc);
16
17 Column c = new Column();
18 c.Alias = "MI_Style";
19 c.DataType = MIDbType.Style;
20 timt.Columns.Add(c);
21 Table table = MapInfo.Engine.Session.Current.Catalog.CreateTable(timt);
22
23 Geometry g = new MapInfo.Geometry.Point(coordsys,x,y);
24 FeatureGeometry fg = (FeatureGeometry)g;
25
26 SimpleVectorPointStyle svps = new SimpleVectorPointStyle(34,Color.Red,50);
27 CompositeStyle cs = new CompositeStyle(svps);
28
29 MIConnection micon = new MIConnection();
30
31 micon.Open();
32 MICommand micom = micon.CreateCommand();
33 micom.CommandText = "insert into mem values(@obj,@style)";
34 micom.Parameters.Add("@obj",MIDbType.FeatureGeometry);
35 micom.Parameters.Add("@style",MIDbType.Style);
36 micom.Parameters["@obj"].Value = g;
37 micom.Parameters["@style"].Value = cs;
38
39 micom.Prepare();
40 int n = micom.ExecuteNonQuery();
41
42 micom.Cancel();
43 micom.Dispose();
44
45 FeatureLayer fl = new FeatureLayer(table);
46 this.mapControl1.Map.Layers.Add(fl);
47
48
49
50 }Because all geometry is a object , u can create any FeatureGeometry to & add it to the map;the code is all the same except the constructor to create the geometry.
因为几何实体都是对象，所以你可以创建自己的几何实体，并＋到地图上去显示它；所有的代码都是很相似，仅仅是不同类型，其构造方法不同而已。