这代码哪错了怎么改求解答

Public Class CategorySalesData
    'declare class level variables
    Private aDataSet As ConancoolDataSet
    Private CategoriesTableAdapter As ConancoolDataSetTableAdapters.CategoriesTableAdapter
    Private Category_Sales_for_1995TableAdapter As ConancoolDataSetTableAdapters.Category_Sales_for_1995TableAdapter

    'constructor
    Sub New()
        'instantiate dataset and table adapter objects
        aDataSet = New ConancoolDataSet
        CategoriesTableAdapter = New ConancoolDataSetTableAdapters.CategoriesTableAdapter
        Category_Sales_for_1995TableAdapter = New ConancoolDataSetTableAdapters.Category_Sales_for_1995TableAdapter
    End Sub

    'function to fill and return  dataset
    Public Function getData() As ConancoolDataSet
        'fill dataset
        CategoriesTableAdapter.Fill(aDataSet.Categories)
        Category_Sales_for_1995TableAdapter.Fill(aDataSet.Category_Sales_for_1995)
        Return aDataSet
    End Function

    'procedure to update database
    Public Sub updateDatabase(ByVal aDataSet As ConancoolDataSet)
        Try
            ' Update child Deletes.
            If aDataSet.Category_Sales_for_1995.GetChanges(DataRowState.Deleted) IsNot Nothing Then
                'Get changes for the deleted child rows only.
                Dim Category_Sales_for_1995DeleteDataTable As DataTable
                Category_Sales_for_1995DeleteDataTable = aDataSet.Category_Sales_for_1995.GetChanges(DataRowState.Deleted)
                Category_Sales_for_1995TableAdapter.Update(Category_Sales_for_1995DeleteDataTable)
            End If
            ' Update all parent row Adds, Deletes, and Changes.
            If aDataSet.Categories.GetChanges() IsNot Nothing Then
                CategoriesTableAdapter.Update(aDataSet.Categories)
            End If
            ' Update child Adds and Edits.
            If aDataSet.Category_Sales_for_1995.GetChanges(DataRowState.Added + DataRowState.Modified) IsNot Nothing Then
                'Get changes for the added and edited child rows only.
                Dim Category_Sales_for_1995AddDataTable As DataTable
                Category_Sales_for_1995AddDataTable = aDataSet.Category_Sales_for_1995.GetChanges(DataRowState.Added + DataRowState.Modified)
                Category_Sales_for_1995TableAdapter.Update(Category_Sales_for_1995AddDataTable)
            End If
            aDataSet.AcceptChanges()
        Catch ex As Exception
            MessageBox.Show(ex.Message)
        End Try
    End Sub

End Class



我用的是VB语言，下滑线的是显示出错的地方，可是我是按照书上打的，一模一样就不知道怎么错了。求各位解答