大家在实际工作中有没有遇到要在DataGrid中显示带有伸缩层次结构的数据呢？如果你对ADO.NET和SQL Server2000熟悉的话，我们下面就举一个利用VS.NET自带的示例数据库Northwind和VB.NET来说明如何实现这一目标。

首先，我们先准备要显示的带有伸缩层次结构的数据。下面就是要绑定到HierarchicalDataGrid.aspx的VB.NET代码文件HierarchicalDataGrid.aspx.vb的内容：

Imports System.Data.SqlClient

Public Class HierarchicalDataGrid

Inherits System.Web.UI.Page

Protected WithEvents DataGrid1 As System.Web.UI.WebControls.DataGrid

#Region " Web Form Designer Generated Code "

\'下面的调用对Web Form设计器来说是必须的

<System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()

End Sub

Private Sub Page_Init(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Init

\'CODEGEN: 这个方法是为Web Form设计器调用的

\'不要用代码编辑器改变这里.

InitializeComponent()

End Sub

#End Region

Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

\'打开数据库连接

Dim OrdersConnection As New SqlConnection("Server=(local)\\NetSDK;Database=northwind;Trusted_Connection=yes")

\'得到订单和订单详细信息

Dim OrderAdapter As New SqlDataAdapter("Select * from Orders; select OrderID ,Products.ProductName,[order Details].Unitprice,[order Details].Quantity,[order Details].discount from [order Details],Products where [Order Details].ProductId=Products.ProductID", OrdersConnection)

\'创建并填充DataSet对象

Dim OrderDataSet As New DataSet()

OrderAdapter.Fill(OrderDataSet)

\'设定表名字

OrderDataSet.Tables(0).TableName = "Orders"

OrderDataSet.Tables(1).TableName = "Order Details"

\'在基于OrderID字段的两个表之间建立父子关系

Dim Parent As DataColumn = OrderDataSet.Tables("Orders").Columns("OrderID")

Dim Child As DataColumn = OrderDataSet.Tables("Order Details").Columns("OrderID")

Dim OrderRelation As DataRelation = New DataRelation("OrderRelation", Parent, Child, False)

\'为DataSet添加关系

OrderDataSet.Relations.Add(OrderRelation)

\'把DataGrid绑定到Orders表

DataGrid1.DataSource = OrderDataSet.Tables("Orders").DefaultView

DataBind()

End Sub

Private Sub DataGrid1_ItemDataBound(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.DataGridItemEventArgs) Handles DataGrid1.ItemDataBound

e.Item.Cells(0).BackColor = System.Drawing.Color.Ivory

End Sub

End Class