手动建立主从表关系数据库显示

Dim   dsOrdersAndDetails   As   New   DataSet ()

          '两个SqlDataAdapter，一个用来读取Orders表，

          '一个用来读取Order Details表

          Dim   daOrders   As   New   SqlClient.   SqlDataAdapter ()

          Dim   daDetails   As   New   SqlClient.   SqlDataAdapter ()

          '数据库连接

          Dim   conn   As   New   SqlClient.   SqlConnection ()

          '建立两个数据表，一个代表Orders表，

          '一个代表OrderDetails表

          Dim   tblOrders   As   New   DataTable ()

          Dim   tblDetails   As   New   DataTable ()

          '把两个数据表加入到数据集中

        dsOrdersAndDetails.Tables.Add(tblOrders)

        dsOrdersAndDetails.Tables.Add(tblDetails)

          '设置数据库连接字符串

        conn.ConnectionString =   "Data Source=(local);Initial Catalog=wb2012;Integrated Security=SSPI"

          '设置读取数据的SQL命令

        daOrders.SelectCommand =   New   SqlClient. SqlCommand   ( "Select * From Fi_mCustomer" , conn)

        daDetails.SelectCommand =   New   SqlClient. SqlCommand   ( "Select * From [Fi_Customer]" , conn)

          '打开数据库连接，填充两个数据表

        conn.Open()

        daOrders.Fill(tblOrders)

        daDetails.Fill(tblDetails)

        conn.Close()

          '开始建立两个数据表之间的关联

          '必须在数据表被填充以后建立关联，因为在那以前，两个数据表都是空的

          '关联也无从谈起

          Dim   rltOrdersToDetails   As   DataRelation

          '第一个参数是关联的名字，就像Case7_5中的OrdersOrder_x0020_Details

          '第二个参数是主子段，也就是主表中的OrderID

          '第三个参数是从字段，也就是从表中的OrderID

        rltOrdersToDetails =   New   DataRelation   ( "Orders_To_Details" , _

                                         tblOrders.Columns( "cid"   ), _

                                         tblDetails.Columns( "cid"   ))

          '把建立好的关联加入数据集

        dsOrdersAndDetails.Relations.Add(rltOrdersToDetails)

          Me .DataGridView1.DataSource = tblOrders

          Me .DataGridView2.DataSource = tblOrders

          Me .DataGridView2.DataMember =   "Orders_To_Details"