有两个表order(orderid,ordername,totalprice), orderdetail(orderid,productid,productname,price) 已经建立一对多 关联(orderid). 用VB.net建立一个窗体, 用于主表和明细表的数据录入及更新. 在窗体上增加两个sqldataadapter,分别选择order和orderdetail表, 并生成数据集,在DATASET中建立关联(orderid)
主表中:ORDERID,ORDERNAME 绑定在两个TEXTBOX文本框中,用于接受用户的输入,totalprice接受明细表中price 的汇总值. 明细表绑定到一个DATAGRID控件, datasource:dsorder; datamember:order.orderorderdetail建立的关联名称
问题:
在主表中新增一个记录,用户录入orderid和ordername后,进入明细表的录入,用户录入productid, productname, price后,提示
“明细orderID列不允许空值，要更正该值吗？” 是什么原因? 用于连接主表的明细orderID如果输入跟主表一样的orderID时提示“ForeignKeyconstraint 要求在交叉表中存在子键值。要更正该值吗？”
只有录入主表中的orderid和ordername后, 先更新主表数据源,才可以编辑更新明细表,这是为什么?
请问,有没有其他更好的方法, 实现主表和明细表的新增记录同时更新呢?
谢谢关照！
网友：方宇
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附部分源代码: Public Class fmOrders Inherits System.Windows.Forms.Form Dim WithEvents dtOrderDetails As New DataTable() Dim BmOrders As BindingManagerBase Dim BmOrderDetails As BindingManagerBase Dim OrderDetailsHasChange As Boolean Dim orderid As DataColumn dim ordername as datacolumn Dim SubTotal As DataColumn
Private Sub bnFirst_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles bnFirst.Click BmOrders.Position = 0 End Sub Private Sub bnPrior_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles bnPrior.Click BmOrders.Position -= 1 End Sub Private Sub bnNext_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles bnNext.Click BmOrders.Position += 1 End Sub Private Sub bnLast_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles bnLast.Click BmOrders.Position = BmOrders.Count - 1 End Sub
Private Sub bnAdd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles bnAdd.Click Try BmOrders.EndCurrentEdit() BmOrders.AddNew()
Catch err As System.SystemException MessageBox.Show(err.ToString) End Try End Sub Private Sub bnLoad_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles bnLoad.Click FillData() End Sub
Private Sub bnUpdate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles bnUpdate.Click Dim dsTestOrdersChange As DataSet
BmOrderDetails.EndCurrentEdit() BmOrders.EndCurrentEdit() If Not dsTestOrders.HasChanges(DataRowState.Deleted) Then Try daOrders.Update(dsTestOrders, "Orders") daOrderDetails.Update(dsTestOrders, "OrderDetails") dsTestOrders.AcceptChanges() Catch err As System.SystemException dsTestOrders.RejectChanges() MessageBox.Show(err.ToString) Throw End Try Else Try daOrderDetails.Update(dsTestOrders, "OrderDetails") daOrders.Update(dsTestOrders, "Orders") dsTestOrders.AcceptChanges() Catch err As System.SystemException dsTestOrders.RejectChanges() MessageBox.Show(err.ToString) Throw End Try End If End Sub
Private Sub fmOrders_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load FillData() dtOrderDetails = dsTestOrders.Tables("OrderDetails") BmOrders = Me.BindingContext(dsTestOrders, "Orders") BmOrderDetails = Me.BindingContext(dsTestOrders, "Orders.OrdersOrderDetails") OrderDetailsHasChange = True SubTotal = dsTestOrders.Tables("Orders").Columns("SubTotal") SubTotal.DefaultValue = 0 Price = dsTestOrders.Tables("OrderDetails").Columns("Price") Price.DefaultValue = 0 End Sub
Private Sub FillData() dsTestOrders.EnforceConstraints = False daOrders.Fill(dsTestOrders) daOrderDetails.Fill(dsTestOrders) dsTestOrders.EnforceConstraints = True End Sub Private Sub dtOrderDetails_ColumnChanged(ByVal sender As Object, ByVal e As System.Data.DataColumnChangeEventArgs) _ Handles dtOrderDetails.ColumnChanged
Dim drOrders As DataRow Dim drOrderDetails As DataRow Dim iSubTotal As Integer Try If OrderDetailsHasChange Then OrderDetailsHasChange = False drOrders = dsTestOrders.Tables("Orders").Rows(BmOrders.Position) iSubTotal = 0 For Each drOrderDetails In drOrders.GetChildRows("OrdersOrderDetails")
iSubTotal = iSubTotal + drOrderDetails("price") Next drOrders.BeginEdit() drOrders("SubTotal") = iSubTotal drOrders.EndEdit() End If Finally OrderDetailsHasChange = True End Try End Sub
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