一，查找圖元
   mapx查找地圖上的圖元有多種方法

  a, FindObj.Search
    這種方法在用的時候有局限性：數據集必須要有索引，查找的字段類型不能是10進制類型（可能還有其它的類型，忘了），否則在圖上找不到。

     Set FindObj = fMainForm.Map1.Layers(LayerCombo.Text).Find
    Set FindObj.FindDataset = fMainForm.Map1.DataSets(LayerCombo.Text & " dataset")
    Set FindObj.FindField = FindObj.FindDataset.Fields(FieldCombo.Text)
    Set FoundFeature = FindObj.Search(FindText.Text)

If FoundFeature.FindRC Mod 10 = 1 Or FoundFeature.FindRC Mod 10 = 2 Then       
       fMainForm.Map1.Layers(LayerCombo.Text).Selection.Add FoundFeature
        fMainForm.Map1.AutoRedraw = False
        fMainForm.Map1.CenterX = FoundFeature.CenterX
        fMainForm.Map1.CenterY = FoundFeature.CenterY
   End If

  b,SQL語句方法

Dim ftrs As MapXLib.Features
Dim lyr As Layer
Dim i As Integer

 Set lyr = fMainForm.Map1.Layers(RoadlyrName)
 Dim strs As String
 strs = Trim("路線編碼 = " + Chr(34) + ComRoadID.List(ComRoadID.ListIndex) + Chr(34))‘在值前面加雙引號如：ID="001",         觀測點名稱 like "%天平莊"
  Set ftrs = lyr.Search(strs)
  lyr.Selection.ClearSelection
 lyr.Selection.Add ftrs
 If ftrs.Count > 0 Then
 fMainForm.Map1.CenterX = ftrs.Item(1).CenterX
 fMainForm.Map1.CenterY = ftrs.Item(1).CenterY
 End If

二，顯示鼠標當前的經緯度
 Private Sub Map1_MouseMove(Button As Integer, Shift As Integer, x As Single, y As Single)
      Dim MX As Double, MY As Double
      Map1.ConvertCoord x, y, MX, MY, 1
   
        Text1.Item(1).Caption = "當前位置"
        Text1.Item(2).Caption = "東經 " & Format(MX, "###0.0000") + ",北緯 " + Format(MY, "###0.0000")                
        Text1.Item(3).Caption = " 當前圖層"
        Text1.Item(4).Caption = Map1.Layers(1).Name
End Sub

14自動滾屏
 Private Sub Map1_MouseMove(Button As Integer, Shift As Integer, x As Single, y As Single)
 If mnuMoveCenter.Checked = True Then
    If x > Map1.MapScreenWidth - 10 Then
    
    Map1.CenterX = Map1.CenterX + 0.05
    
    Map1.Refresh
    
    Else
    
    If x < 10 Then
    
    Map1.CenterX = Map1.CenterX - 0.05
    
    Map1.Refresh
    
    Else
    
    If y > Map1.MapScreenHeight - 10 Then
    
    Map1.CenterY = Map1.CenterY - 0.05
    
    Map1.Refresh
    
    Else
    
    If y < 10 Then
    
    Map1.CenterY = Map1.CenterY + 0.05
    
    Map1.Refresh
    
    End If
    
    End If
    
    End If
    
    End If
End If
 End Sub


15測距和測面積
Private Sub Form_Load()
  Map1.CreateCustomTool PolyRulerToolID, miToolTypePoly, miSizeAllCursor
    Map1.CreateCustomTool PolyAreaToolID, miToolTypePolygon, miSelectRegionMinusCursor
End Sub


 Private Sub Map1_PolyToolUsed(ByVal ToolNum As Integer, ByVal flags As Long, ByVal Points As Object, ByVal bShift As Boolean, ByVal bCtrl As Boolean, EnableDefault As Boolean)
    If ToolNum = PolyRulerToolID Then
        Dim i As Integer
        Dim DistanceSoFar As Double
        Map1.MapUnit = RulerUnit
        DistanceSoFar = 0#
        If Points.Count > 1 Then
            For i = 2 To Points.Count
                DistanceSoFar = DistanceSoFar + Map1.Distance(Points.Item(i).x, Points.Item(i).y, Points.Item(i - 1).x, Points.Item(i - 1).y)
            Next
        End If
        If flags = miPolyToolEnd Then
            'First, clear the status bar
            
            Text1.Item(4).Caption = ""
            MsgBox "距離: " & DistanceSoFar & " " & RulerUnitString
        Else
            Text1.Item(3).Caption = "距離"
             Text1.Item(4).Caption = DistanceSoFar & " " & RulerUnitString
        End If
    End If
    If ToolNum = PolyAreaToolID Then
    '面積
     
     Map1.AreaUnit = miUnitSquareKilometer
    On Error Resume Next
    Dim apolygoN As New MapXLib.Feature
    Dim ax As Double
    If (Points.Count > 2) Then
    Set apolygoN = New Feature
    Set apolygoN = Map1.FeatureFactory.CreateRegion(Points)
    ax = apolygoN.Area
    MsgBox "面積: " & ax
    End If
        
End If

End Sub