数据库类,该如何解决

Imports System.Data.Common

Public Class Form1

    Private db As New LzmTW.Data.SqlDatabase("(local)", "NorthWind")
    Private cm As DbCommand
    Private ds As New DataSet

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        cm = db.CreateCommand("[Sales by Year]", True)
        db.AddParameter(cm, "Beginning_Date").DbType = DbType.DateTime
        db.AddParameter(cm, "Ending_Date").DbType = DbType.DateTime


        db.SetParameterValue(cm, "Beginning_Date", #7/4/1996#)
        db.SetParameterValue(cm, "Ending_Date", #9/4/1996#)
        db.Load(cm, ds, "1996")

        db.SetParameterValue(cm, "Beginning_Date", #7/4/1997#)
        db.SetParameterValue(cm, "Ending_Date", #9/4/1997#)
        db.Load(cm, ds, "1997")

        db.Load("SELECT * FROM ORDERS;SELECT * FROM REGION", ds, New String() {"ORDERS", "REGION"})
    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click

        Me.DataGridView1.DataSource = ds.Tables("1996")
    End Sub

    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
        Me.DataGridView1.DataSource = ds.Tables("1997")
    End Sub

    Private Sub Button5_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button5.Click
        Me.DataGridView1.DataSource = ds.Tables("ORDERS")
    End Sub

    Private Sub Button6_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button6.Click
        Me.DataGridView1.DataSource = ds.Tables("REGION")
    End Sub

    Private Sub Button7_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button7.Click
        Dim db As New LzmTW.Data.ExcelDatabase("g:\dd.xls")
        Console.WriteLine(db.ToExcel(New String() {"[AA$]", "[BB$]"}, "g:\t.xls", New String() {"AA", "BB"}))
    End Sub


End Class