在mapControl控件上添加feature要素

ArcGIS Engine没有提供在MapControl中点击查询的命令，只是提供了ReaderControl中的使用的点击查询的命令，下面的代码就是实现点击查询并闪烁的代码。

过程描述

Private Sub MapControl1_OnMouseDown(ByVal button As Long, ByVal shift As Long, ByVal x As Long, ByVal y As Long, ByVal mapX As Double, ByVal mapY As Double)
Dim pMap As IMap

Dim i As Integer
Dim pPoint As IPoint
Set pMap = MapControl1.Map
Set pPoint = MapControl1.ActiveView.ScreenDisplay.DisplayTransformation.ToMapPoint(x, y)

Dim pIdentify As IIdentify

Dim pIDArray As IArray
Dim pFeatIdObj As IFeatureIdentifyObj
Dim pIdObj As IIdentifyObj
Set pIdentify = pMap.Layer(1)

Dim pEnv As IEnvelope
Set pEnv = New Envelope
Set pEnv = MapControl1.ActiveView.Extent
pEnv.Height = 100
pEnv.Width = 100
pEnv.CenterAt pPoint

Set pIDArray = pIdentify.Identify(pEnv)

If Not pIDArray Is Nothing Then
Set pFeatIdObj = pIDArray.Element(0)
Set pIdObj = pFeatIdObj
pIdObj.Flash MapControl1.ActiveView.ScreenDisplay
'消息显示查询目标的信息
MsgBox "Layer:" & pIdObj.Layer.Name & vbNewLine & "Feature:" & pIdObj.Name
Else
MsgBox "No feature identified."
End If
End Sub