求教！

HI , Good morning everyone ,请指点一下：“Set Nftr1 = Map1.Layers.Item("Try").Selection.Item(1)“这句的错误是："No object was found using the index you specified" Why? thanks! Dim Nftr1 As Feature Dim Nftr2 As Feature Dim ff As FeatureFactory Dim Myftrs As Parts Dim Myftr As Points Dim pnts As Points Dim pnt As Point Dim Npnt As New Point Dim Npnts As New Points Dim MyNftr As Feature Dim x As Double Dim Y As Double Set Nftr1 = Map1.Layers.Item("Try").Selection.Item(1) Set Nftr2 = Map1.Layers.Item("Try").Selection.Item(2) Set ff = Map1.FeatureFactory   If ff.IntersectionTest(Nftr1, Nftr1, 1) Then     MsgBox "交*", , "提示"     Set Nftr = ff.CombineFeatures(Nftr1, Nftr1)     Set Myftrs = Nftr.Parts     For Each Myftr In Myftrs       Set pnts = Myftr       For Each pnt In pnts         x = pnt.x * 1 / 2         Y = pnt.Y * 1 / 2         Npnt.Set x, Y         Npnts.Add Npnt       Next         Set MyNftr = ff.CreateRegion(Npnts)         Set MyNftr = Map1.Layers(1).AddFeature(MyNftr)         MyNftr.Style.RegionColor = RGB(255, 0, 0)         MyNftr.Style.RegionPattern = miPatternDiagCross         Map1.Layers.Item("Try").AddFeature MyNftr         MyNftr.Update            Next   Else     MsgBox "无交*", , "提示"   End If