请问怎样实现鼠标点击选定对象？

<P>请问怎样实现鼠标点击选定对象？　比如用鼠标框一个方框可以选择地图上的几个州</P>
<P>AO中帮助的代码为</P>
<P>Public Sub SelFeatures()<BR>  Dim pMxDoc As IMxDocument<BR>  Dim pMap As IMap<BR>  Dim pFeatSel As IFeatureSelection<BR>  Dim pQF As IQueryFilter<BR>  Dim pSelSet As ISelectionSet<BR>  <BR>  Set pMxDoc = Application.Document<BR>  Set pMap = pMxDoc.FocusMap<BR>  Set pFeatSel = pMap.Layer(0)<BR>  <BR>  ' set up query filter with where clause<BR>  Set pQF = New QueryFilter<BR>  pQF.WhereClause = "POP2000 > 200000"　　　／／我想在此修改<BR>  <BR>  ' perform selection<BR>  pFeatSel.SelectFeatures pQF, esriSelectionResultNew, False<BR>  pFeatSel.SelectionChanged<BR>  pMxDoc.ActiveView.PartialRefresh esriViewGeography, Nothing, Nothing<BR>  <BR>  ' report number of selected features<BR>  Set pSelSet = pFeatSel.SelectionSet<BR>  MsgBox pSelSet.Count<BR>  <BR>End Sub</P>
<P>但这个代码是限定一定的检索条件的，怎么改成鼠标的点击选取方式．谢谢！</P>