form04.frm

给出了详细的vb环境下mo基本功能的代码 如图层的加载

VERSION 5.00
Object = "{9BD6A640-CE75-11D1-AF04-204C4F4F5020}#2.0#0"; "mo20.ocx"
Begin VB.Form Form04 
   Caption         =   "墨西哥地图"
   ClientHeight    =   5415
   ClientLeft      =   60
   ClientTop       =   345
   ClientWidth     =   6765
   LinkTopic       =   "Form1"
   ScaleHeight     =   5415
   ScaleWidth      =   6765
   StartUpPosition =   3  '窗口缺省
   Begin VB.CommandButton Command1 
      Caption         =   "Command1"
      Height          =   495
      Left            =   2880
      TabIndex        =   1
      Top             =   4800
      Width           =   1215
   End
   Begin MapObjects2.Map Map1 
      Height          =   4575
      Left            =   0
      TabIndex        =   0
      Top             =   0
      Width           =   6735
      _Version        =   131072
      _ExtentX        =   11880
      _ExtentY        =   8070
      _StockProps     =   225
      BackColor       =   16777215
      BorderStyle     =   1
      Contents        =   "Form04.frx":0000
   End
End
Attribute VB_Name = "Form04"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
'Xuewei,2003/6/10
'使用SQL数据库向属性数据库写数据；

Option Explicit

Private Sub DrawLayer()
  Dim Layer As MapLayer
  Dim dc As New DataConnection
   
  On Error GoTo Err1
  dc.Database = App.Path + "\..\" + "Mexico"
  Set Layer = New MapLayer
  Set Layer.GeoDataset = dc.FindGeoDataset("states")
  Layer.Symbol.Color = moLimeGreen
  Map1.Layers.Add Layer
  
  Set Layer = New MapLayer
  Set Layer.GeoDataset = dc.FindGeoDataset("CITIES")
  Layer.Symbol.Color = moRed
  Map1.Layers.Add Layer
  Exit Sub
  
Err1:
  If dc.ConnectError = 0 Then
    MsgBox "没找到图层", vbInformation, "MO示例"
  Else
    MsgBox ConnectErrorMsg(dc.ConnectError), vbInformation, "MO示例"
  End If
  End
End Sub

Private Sub Command1_Click()
  Dim Recs As MapObjects2.Recordset
  Dim Layer As MapObjects2.MapLayer
  Dim Rst1 As ADODB.Recordset
  Dim Str1 As String
  
  On Error GoTo Err1
  Str1 = InputBox("输入年度", "MO示例", "2002")
  Set Rst1 = New ADODB.Recordset
  Rst1.Open "select * from cities where RYEAR = '" & Str1 & "'", Cnn1, adOpenStatic, adLockReadOnly
  
  Set Layer = Map1.Layers("cities")
  Set Recs = Layer.Records
  Do While Not Recs.EOF
    Recs.Edit
    Recs!POPULATION = Rst1!POPULATION
    Recs.Update
    Recs.MoveNext
    Rst1.MoveNext
  Loop
  
  Set Recs = Nothing
  Set Rst1 = Nothing
  MsgBox "修改完成"
  Exit Sub
  
Err1:
  MsgBox "输入错误"
End Sub

Private Sub Form_Load()
  DrawLayer   '加载墨西哥地图的States和Cities图层；
  SetSQLDb
  Command1.Caption = "写入数据"
End Sub