应用MapX编程实现地图数据查询

王朝vb·作者佚名  2006-01-09
窄屏简体版  字體: |||超大  

0、综述

应用MapX控件实现查询的功能并不太难。MapX为我们提供了Find、FindFeature等对象,可以用来实现我们需要的功能:)

1、本程序实现从下列表中选择一个节点,并以此节点为中心进行进行定位的功能(实例以第一层RTUName属性的值进行查询)

Private Sub Command1_Click()

Dim FindObj As MapXLib.Find

Dim FoundFeature As FindFeature

'从要查询的RTU图层生成Find对象,并为这个对象设置要查询的FindDataSet、FindField属性

Set FindObj = Form1.Map1.Layers.Item(1).Find

Set FindObj.FindDataset = Form1.Map1.DataSets("RTU节点" & " dataset")

Set FindObj.FindField = FindObj.FindDataset.Fields("RTUName")

Set FoundFeature = FindObj.Search(Combo1.Text)

Me.Hide

' 关掉AutoRedraw是因为CenterX(Y)的改变就要刷新图层,AutoRedraw打开的话会造成二次刷新

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写一下,实现按照用户输入的字段进行查询定位的功能:

Private Sub Command2_Click()

Dim FindObj As MapXLib.Find

Dim FoundFeature As FindFeature

'从要查询的RTU图层生成Find对象,并为这个对象设置要查询的FindDataSet、FindField属性

Set FindObj = Form1.Map1.Layers.Item(1).Find

Set FindObj.FindDataset = Form1.Map1.DataSets("RTU节点" & " 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

' 关掉AutoRedraw是因为CenterX(Y)的改变就要刷新图层,AutoRedraw打开的话会造成二次刷新

Form1.Map1.AutoRedraw = False

Form1.Map1.CenterX = FoundFeature.CenterX

Form1.Map1.CenterY = FoundFeature.CenterY

Form1.Show

Else

MsgBox "不存在该RTU节点!"

End If

End Sub

 
 
 
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