[编程交流] PromptSelectionResult不起作用

     Public Sub FindBlockInFrame(frame As Extents3d)
           Dim tvs As TypedValue() = New TypedValue() _
           {
               New TypedValue(DxfCode.Start, "INSERT"),
               New TypedValue(DxfCode.BlockName, "myblock")
           }
           Dim filter As New SelectionFilter(tvs)
           Dim selection As PromptSelectionResult = ed.SelectCrossingWindow(frame.MinPoint, frame.MaxPoint, filter)
           'Dim selection As PromptSelectionResult = ed.SelectWindow(frame.MinPoint, frame.MaxPoint, filter)
           If selection.Status <> PromptStatus.OK Then
               Return
           End If
           Using tr As Transaction = db.TransactionManager.StartTransaction()
               Dim list As New List(Of BlockReference)
               For Each id As ObjectId In selection.Value.GetObjectIds()
                   Dim block As BlockReference = DirectCast(tr.GetObject(id, OpenMode.ForRead), BlockReference)
                   list.Add(block)
               Next
               ed.WriteMessage(vbLf & "block count in frmae  {0})", list.Count)
               tr.Commit()
           End Using
       End Sub