请教：用户定义类型未定义

以下程序哪里错拉
Private Sub Command7_Click()
  Dim dc As New DataConnection
  Dim gs As GeoDataset
  Dim name As String
  Dim layer As MapObjects.MapLayer     ‘显示这句有问题。不解
  CommonDialog1.Filter = "ESRI Shapefiles (*.shp)|*.shp"
  CommonDialog1.ShowOpen
  If Len(CommonDialog1.FileName) = 0 Then Exit Sub
  dc.Database = CurDir
  If Not dc.Connect Then Exit Sub
  name = Left(CommonDialog1.FileTitle, Len(CommonDialog1.FileTitle) - 4)
  Set gs = dc.FindGeoDataset(name)
  If gs Is Nothing Then Exit Sub
  Set layer = New MapLayer
  layer.GeoDataset = gs
  Map1.Layers.Add layer
End Sub

已经解决。