應用MapX控件實現查詢的功能並不太難。MapX爲我們提供了Find、FindFeature等對象,可以用來實現我們需要的功能:
1、本程序實現從下列表中選擇一個節點,並以此節點爲中心進行進行定位的功能(實例以第一層RTUName屬性的值進行查詢)
Private Sub Command1_Click()
Dim FindObj As MapXLib.Find
Dim FoundFeature As FindFeature
'從要查詢的RTU圖層生成Find對象,併爲這個對象設置要查詢的FindDataSet、FindField屬性
Set FindObj = Form1.Map1.Layers.Item(1).Find
Set FindObj.FindDataset = Form1.Map1.DataSets("RTU節點" & " dataset")
Set FindObj.FindField = FindObj.FindDataset.Fields("RTUName")
Set FoundFeature = FindObj.Search(Combo1.Text)
Me.Hide
' 關掉AutoRedraw是因爲CenterX(Y)的改變就要刷新圖層,AutoRedraw打開的話會造成二次刷新
Form1.Map1.AutoRedraw = False
Form1.Map1.CenterX = FoundFeature.CenterX
Form1.Map1.CenterY = FoundFeature.CenterY
Form1.Show
End Sub
2、把上面的程序稍微改寫一下,實現按照用戶輸入的字段進行查詢定位的功能:
Private Sub Command2_Click()
Dim FindObj As MapXLib.Find
Dim FoundFeature As FindFeature
'從要查詢的RTU圖層生成Find對象,併爲這個對象設置要查詢的FindDataSet、FindField屬性
Set FindObj = Form1.Map1.Layers.Item(1).Find
Set FindObj.FindDataset = Form1.Map1.DataSets("RTU節點" & " dataset")
Set FindObj.FindField = FindObj.FindDataset.Fields("RTUName")
Set FoundFeature = FindObj.Search(Text1.Text)
If FoundFeature.FindRC Mod 10 = 1 Or FoundFeature.FindRC Mod 10 = 2 Then
Me.Hide
' 關掉AutoRedraw是因爲CenterX(Y)的改變就要刷新圖層,AutoRedraw打開的話會造成二次刷新
Form1.Map1.AutoRedraw = False
Form1.Map1.CenterX = FoundFeature.CenterX
Form1.Map1.CenterY = FoundFeature.CenterY
Form1.Show
Else
MsgBox "不存在該RTU節點!"
End If
End Sub