如何用VB.Net创建一个三层的数据库应用程序

''
  
   Me.DataGrid1.DataMember = ""
  
   Me.DataGrid1.Location = New System.Drawing.Point(40, 56)
  
   Me.DataGrid1.Name = "DataGrid1"
  
   Me.DataGrid1.Size = New System.Drawing.Size(480, 264)
  
   Me.DataGrid1.TabIndex = 3
  
   ''
  
   ''Form1
  
   ''
  
   Me.AutoScaleBaseSize = New System.Drawing.Size(6, 14)
  
   Me.ClientSize = New System.Drawing.Size(568, 429)
  
   Me.Controls.AddRange(New System.Windows.Forms.Control() {Me.DataGrid1, Me.Button3, Me.Button2, Me.Button1})
  
   Me.Name = "Form1"
  
   Me.Text = "Form1"
  
   CType(Me.Client_DataSet, System.ComponentModel.ISupportInitialize).EndInit()
  
   CType(Me.DataGrid1, System.ComponentModel.ISupportInitialize).EndInit()
  
   Me.ResumeLayout(False)
  
   End Sub
  
  #End Region
  
   Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
  
   Dim Customer_Ds As New localhost.super_ds()
  
   Dim ser1 As New localhost.Service1()
  
   Customer_Ds.Merge(ser1.Get_Dataset)
  
   DataGrid1.DataSource = Customer_Ds
  
   End Sub
  
  End Class
  
  总结：可见，表示层窗体上完全没有数据库连接控件，它与数据库的连接任务是通过业务层来完成的，这样，程序的结构更加清晰，当然业务层的实现也可以用其他方法，比如：写一个自己的类来完成与数据库的数据传输。
  
  (转自51dotnet)