[求助]IIdentify问题

<P>为什么我用IIdentify只能获得面要素，而对于点、线却总是获取不到？代码如下：</P>
<P>public override void OnMouseDown(int Button, int Shift, int X, int Y)<BR>  {<BR>   base.OnMouseDown (Button, Shift, X, Y);<BR>   <BR>   //Get the active view<BR>   IActiveView activeView = m_HookHelper.ActiveView;<BR>   map = activeView.FocusMap;<BR>   identify = map.get_Layer(0) as IIdentify;<BR>   point = activeView.ScreenDisplay.DisplayTransformation.ToMapPoint(X, Y);<BR>   idArray = identify.Identify(point);</P>
<P>   if (idArray != null)<BR>   {<BR>    featIdObj = idArray.get_Element(0) as IFeatureIdentifyObj;<BR>    idObj = featIdObj as IIdentifyObj;<BR>    idObj.Flash(activeView.ScreenDisplay);<BR>    MessageBox.Show("Layer: " + idObj.Layer.Name + "\n" + "Feature: " + idObj.Name);<BR>   }<BR>  }</P>
<P>请各位高手多执教。</P>

<P>因为你没有点中,:),在你的程序里,是需要用户精确的点中要素才显示相关信息的;你可以参照下面的例子,在点的附近建立一个矩形区域来查询要素</P>
<H1>FeatureIdentifyObject Example</H1><PRE><PRE><PRE><P>The following UIToolControl code uses the <STRONG>IIdentify::Identify </STRONG>method to get the <STRONG>FeatureIdentifyObject</STRONG> objects at the mouse-click location. Then, using the <STRONG>IIdentifyObj </STRONG>interface, some of the properties of the feature first identified are reported.</P><CODE><PRE>Private Sub UIToolControl1_MouseDown(ByVal button As Long, _<BR>              ByVal shift As Long, ByVal x As Long, ByVal y As Long)<BR>  Dim pMxApp As IMxApplication<BR>  Dim pDoc As IMxDocument<BR>  Dim pMap As IMap<BR>  Dim pIdentify As IIdentify<BR>  Dim pIDArray As IArray<BR>  Dim pFeatIdObj As IFeatureIdentifyObj<BR>  Dim pIdObj As IIdentifyObj<BR>  Dim tol As Long<BR>  Dim pEnv As IEnvelope<BR>  Dim r As tagRECT<BR>  <BR>  Set pMxApp = Application<BR>  Set pDoc = Application.Document<BR>  Set pMap = pDoc.FocusMap<BR>  Set pIdentify = pMap.Layer(0)<BR>  tol = pDoc.SearchTolerancePixels<BR>  <BR>  'consruct a small rectangle out of the x,y coord and the document's pixel tolerance<BR>  r.Left = x - tol 'upper left x, top left is 0,0<BR>  r.Top = y - tol 'upper left y, top left is 0,0<BR>  r.Right = x + tol 'lower right x, top left is 0,0<BR>  r.bottom = y + tol 'lower right y, top left is 0,0<BR>  <BR>  'Tranform the device rectange into a geographic rectangle via the display transformation<BR>  Set pEnv = New Envelope<BR>  pMxApp.Display.DisplayTransformation.TransformRect pEnv, r, esriTransformPosition + esriTransformToMap<BR>  <BR>  'setup the spatial reference on the newly hydrated envelope<BR>  Set pEnv.SpatialReference = pMap.SpatialReference<BR>  <BR>  'identify with the envelope<BR>  Set pIDArray = pIdentify.Identify(pEnv)<BR>  <BR>  'Get the FeatureIdentifyObject<BR>  If Not pIDArray Is Nothing Then<BR>    Set pFeatIdObj = pIDArray.Element(0)<BR>    Set pIdObj = pFeatIdObj<BR>    pIdObj.Flash pMxApp.Display<BR>    'Report info from FeatureIdentifyObject<BR>    MsgBox "Layer: " ; pIdObj.Layer.Name ; vbNewLine ; "Feature: " ; pIdObj.Name<BR>  Else<BR>    MsgBox "No feature identified."<BR>  End If<BR>End Sub<BR></PRE></CODE></PRE></PRE></PRE>

多谢总统，但是我用的是AE，里面没有IMxDocument接口那我应该怎样获得那个容差呢？