处理 SMO 事件

某些服务器事件类型可以通过使用事件处理程序和 ServerConnection 对象来进行订阅。

当服务器上发生某些操作时，SQL Server 管理对象 (SMO) 中的许多实例类可以触发事件。

通过设置事件处理程序并订阅相关事件，可以以编程方式对这些事件进行处理。 这种事件处理只是暂时性的，因为当 SMO 客户端程序退出时会删除所有的订阅。

ConnectionContext 事件处理

ServerConnection 对象支持若干种事件类型。 事件属性必须设置为相应事件处理程序的实例，且必须将事件处理程序对象定义为用于处理事件的受保护函数。

事件订阅

您可以通过以下方法处理事件：编写事件处理程序类，创建该类的实例，将事件处理程序分配给父对象，然后订阅事件。

必须编写事件处理程序类才能处理事件。 事件处理程序类可以包含多个事件处理程序函数，且只有在安装事件处理程序类后才能处理事件。 事件处理程序函数将从可用于报告事件相关信息的 ServerEventNotificatificationArgs 参数接收关于事件的信息。

DatabaseEventSet 类和 ServerEventSet 类中列出了可以进行处理的数据库和服务器事件的类型。

示例

若要使用所提供的任何代码示例，您必须选择创建应用程序所需的编程环境、编程模板和编程语言。有关详细信息，请参阅 SQL Server 联机丛书中的“如何在 Visual Studio .NET 中创建 Visual Basic SMO 项目”或“如何在 Visual Studio .NET 中创建 Visual C# SMO 项目”。

在 Visual Basic 中注册事件处理程序并订阅事件处理

此代码示例演示如何设置事件处理程序以及如何订阅数据库事件。

'Create an event handler subroutine that runs when a table is created.
Private Sub MyCreateEventHandler(ByVal sender As Object, ByVal e As ServerEventArgs)
    Console.WriteLine("A table has just been added to the AdventureWorks2012 2008 database.")
End Sub
'Create an event handler subroutine that runs when a table is deleted.
Private Sub MyDropEventHandler(ByVal sender As Object, ByVal e As ServerEventArgs)
    Console.WriteLine("A table has just been dropped from the AdventureWorks2012 2008 database.")
End Sub
Sub Main()
    'Connect to the local, default instance of SQL Server.
    Dim srv As Server
    srv = New Server
    'Reference the AdventureWorks2012 database.
    Dim db As Database
    db = srv.Databases("AdventureWorks2012")
    'Create a database event set that contains the CreateTable event only.
    Dim databaseCreateEventSet As New DatabaseEventSet
    databaseCreateEventSet.CreateTable = True
    'Create a server event handler and set it to the first event handler subroutine.
    Dim serverCreateEventHandler As ServerEventHandler
    serverCreateEventHandler = New ServerEventHandler(AddressOf MyCreateEventHandler)
    'Subscribe to the first server event handler when a CreateTable event occurs.
    db.Events.SubscribeToEvents(databaseCreateEventSet, serverCreateEventHandler)
    'Create a database event set that contains the DropTable event only.
    Dim databaseDropEventSet As New DatabaseEventSet
    databaseDropEventSet.DropTable = True
    'Create a server event handler and set it to the second event handler subroutine.
    Dim serverDropEventHandler As ServerEventHandler
    serverDropEventHandler = New ServerEventHandler(AddressOf MyDropEventHandler)
    'Subscribe to the second server event handler when a DropTable event occurs.
    db.Events.SubscribeToEvents(databaseDropEventSet, serverDropEventHandler)
    'Start event handling.
    db.Events.StartEvents()
    'Create a table on the database.
    Dim tb As Table
    tb = New Table(db, "Test_Table")
    Dim mycol1 As Column
    mycol1 = New Column(tb, "Name", DataType.NChar(50))
    mycol1.Collation = "Latin1_General_CI_AS"
    mycol1.Nullable = True
    tb.Columns.Add(mycol1)
    tb.Create()
    'Remove the table.
    tb.Drop()
    'Wait until the events have occured.
    Dim x As Integer
    Dim y As Integer
    For x = 1 To 1000000000
        y = x * 2
    Next
    'Stop event handling.
    db.Events.StopEvents()





End Sub

在 Visual C# 中注册事件处理程序并订阅事件处理

此代码示例演示如何设置事件处理程序以及如何订阅数据库事件。

//Create an event handler subroutine that runs when a table is created. 
private void MyCreateEventHandler(object sender, ServerEventArgs e) 
{ 
Console.WriteLine("A table has just been added to the AdventureWorks2012 database."); 
} 
//Create an event handler subroutine that runs when a table is deleted. 
private void MyDropEventHandler(object sender, ServerEventArgs e) 
{ 
Console.WriteLine("A table has just been dropped from the AdventureWorks2012 database."); 
} 
public void Main() 
{ 
//Connect to the local, default instance of SQL Server. 
Server srv; 
srv = new Server(); 
//Reference the AdventureWorks2012 database. 
Database db; 
db = srv.Databases("AdventureWorks2012"); 
//Create a database event set that contains the CreateTable event only. 
DatabaseEventSet databaseCreateEventSet = new DatabaseEventSet(); 
databaseCreateEventSet.CreateTable = true; 
//Create a server event handler and set it to the first event handler subroutine. 
ServerEventHandler serverCreateEventHandler; 
serverCreateEventHandler = new ServerEventHandler(MyCreateEventHandler); 
//Subscribe to the first server event handler when a CreateTable event occurs. 
db.Events.SubscribeToEvents(databaseCreateEventSet, serverCreateEventHandler); 
    //Create a database event set that contains the DropTable event only. 
DatabaseEventSet databaseDropEventSet = new DatabaseEventSet(); 
databaseDropEventSet.DropTable = true; 
//Create a server event handler and set it to the second event handler subroutine. 
ServerEventHandler serverDropEventHandler; 
serverDropEventHandler = new ServerEventHandler(MyDropEventHandler); 
//Subscribe to the second server event handler when a DropTable event occurs. 
db.Events.SubscribeToEvents(databaseDropEventSet, serverDropEventHandler); 
//Start event handling. 
db.Events.StartEvents(); 
//Create a table on the database. 
Table tb; 
tb = new Table(db, "Test_Table"); 
Column mycol1; 
mycol1 = new Column(tb, "Name", DataType.NChar(50)); 
mycol1.Collation = "Latin1_General_CI_AS"; 
mycol1.Nullable = true; 
tb.Columns.Add(mycol1); 
tb.Create(); 
//Remove the table. 
tb.Drop(); 
//Wait until the events have occured. 
int x; 
int y; 
for (x = 1; x <= 1000000000; x++) { 
    y = x * 2; 
} 
//Stop event handling. 
db.Events.StopEvents(); 
}