本文整理汇总了VB.NET中System.Data.DataTableCollection.CollectionChanging事件的典型用法代码示例。如果您正苦于以下问题：VB.NET DataTableCollection.CollectionChanging事件的具体用法？VB.NET DataTableCollection.CollectionChanging怎么用？VB.NET DataTableCollection.CollectionChanging使用的例子？那么恭喜您, 这里精选的事件代码示例或许可以为您提供帮助。您也可以进一步了解该事件所在类System.Data.DataTableCollection的用法示例。
在下文中一共展示了DataTableCollection.CollectionChanging事件的1个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的VB.NET代码示例。
示例1: TableCollectionCollectionChanging
Public Sub TableCollectionCollectionChanging()
' Create a DataSet with two tables
Dim dataSet As New DataSet()
AddHandler dataSet.Tables.CollectionChanging, _
AddressOf Collection_Changing
' Create Customer table
Dim customersTable As New DataTable("Customers")
customersTable.Columns.Add("customerId", _
System.Type.GetType("System.Integer")).AutoIncrement = True
customersTable.Columns.Add("name", _
System.Type.GetType("System.String"))
customersTable.PrimaryKey = New DataColumn() _
{customersTable.Columns("customerId")}
' Create Orders table
Dim ordersTable As New DataTable("Orders")
ordersTable.Columns.Add("orderId", _
System.Type.GetType("System.Integer")).AutoIncrement = True
ordersTable.Columns.Add("customerId", _
System.Type.GetType("System.Integer"))
ordersTable.Columns.Add("amount", System.Type.GetType("System.Double"))
ordersTable.PrimaryKey = New DataColumn() {ordersTable.Columns("orderId")}
' Add the tables to the DataTableCollection
dataSet.Tables.AddRange(New DataTable() {customersTable, ordersTable})
' Remove all tables
' First check to see if the table can be removed and
' then remove it.
'
' You cannot use a For Each loop to remove items
' from a collection.
Do While (dataSet.Tables.Count > 0)
Dim table As DataTable
table = dataSet.Tables(0)
If (dataSet.Tables.CanRemove(table)) Then
dataSet.Tables.RemoveAt(0)
End If
Loop
Console.WriteLine("dataSet has {0} tables", dataSet.Tables.Count)
End Sub
Private Sub Collection_Changing(ByVal sender As Object, _
ByVal e As System.ComponentModel.CollectionChangeEventArgs)
' Implementing this event allows you to abort a change
' to the collection by raising an exception which you can
' catch.
Console.WriteLine( _
"Collection_Changing Event: '{0}'\table element={1}", _
e.Action.ToString(), e.Element.ToString())
End Sub