form06.frm

这是一个计算面积的程序

VERSION 5.00
Object = "{9BD6A640-CE75-11D1-AF04-204C4F4F5020}#2.0#0"; "mo20.ocx"
Begin VB.Form Form06 
   Caption         =   "Buffer演示"
   ClientHeight    =   4815
   ClientLeft      =   60
   ClientTop       =   345
   ClientWidth     =   6195
   LinkTopic       =   "Form1"
   ScaleHeight     =   4815
   ScaleWidth      =   6195
   StartUpPosition =   3  '窗口缺省
   Begin MapObjects2.Map Map1 
      Height          =   4575
      Left            =   120
      TabIndex        =   0
      Top             =   120
      Width           =   5895
      _Version        =   131072
      _ExtentX        =   10398
      _ExtentY        =   8070
      _StockProps     =   225
      BackColor       =   16777215
      BorderStyle     =   1
      Contents        =   "form06.frx":0000
   End
End
Attribute VB_Name = "Form06"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
'Xuewei,2003/6/5
'line的Buffer示例；

Option Explicit
Const Bdist = 0.5
Dim sym1 As New MapObjects2.Symbol
Dim sym2 As New MapObjects2.Symbol
Dim Line1 As New MapObjects2.Line
Dim buffLine As New MapObjects2.Polygon

Private Sub Map1_MouseDown(Button As Integer, Shift As Integer, x As Single, y As Single)
  Set Line1 = Map1.TrackLine
  Set buffLine = Line1.Buffer(Bdist, Map1.FullExtent)
  Map1.TrackingLayer.Refresh True
End Sub

Private Sub Map1_AfterTrackingLayerDraw(ByVal hDC As stdole.OLE_HANDLE)
  If Not Line1 Is Nothing Then
    Map1.DrawShape Line1, sym1
  End If
  If Not buffLine Is Nothing Then
    Map1.DrawShape buffLine, sym2
  End If
End Sub

Sub DrawLayer()
  Dim dc As New DataConnection
  Dim layer As MapLayer
  dc.Database = App.Path + "\..\" + "Mexico"
  If Not dc.Connect Then
    MsgBox "在指定的文件夹下没找到图层数据文件！"
    End
  End If
  
  Set layer = New MapLayer
  Set layer.GeoDataset = dc.FindGeoDataset("States")
  layer.Symbol.Color = moLimeGreen
  Map1.Layers.Add layer
End Sub


Private Sub Form_Load()
  DrawLayer
  With sym1
    .SymbolType = moLineSymbol
    .Color = moRed
    .Size = 3
  End With
  With sym2
    .SymbolType = moFillSymbol
    .Style = moGrayFill
    .Color = moBlue
    .OutlineColor = moBlue
  End With
End Sub