以程式設計方式處理事件
SSIS 執行階段會提供在驗證和執行封裝之前、期間和之後所發生的事件集合。這些事件可使用兩種方式來擷取。第一個方法是在類別中實作 IDTSEvents 介面，並將此類別當做參數提供給封裝的 Execute 和 Validate 方法。第二個方法是建立 DtsEventHandler 物件，其中可包含當 IDTSEvents 內發生事件時所執行的其他 SSIS 物件 (如工作和迴圈)。本章節描述這兩個方法，並提供示範其使用方式的程式碼範例。
接收 IDTSEvents 回呼
以程式設計方式建立及執行封裝的開發人員，可以在驗證和執行程序期間使用 IDTSEvents 介面來接收事件通知。其處理方式是建立一個類別來實作 IDTSEvents 介面，並將這個類別當做參數提供給封裝的 Validate 和 Execute 方法。然後當事件發生時，執行階段引擎會呼叫此類別的方法。
DefaultEvents 類別是一個已經實作 IDTSEvents 介面的類別；因此，直接實作 IDTSEvents 的另一個方法是衍生自 DefaultEvents，並覆寫您想要回應的特定事件。然後您可以將您的類別當做參數提供給 Package 的 Validate 和 Execute 方法，以接收事件回呼。
下列程式碼範例會示範衍生自 DefaultEvents 的類別，並覆寫 OnPreExecute 方法。然後此類別會當做參數提供給此封裝的 Validate 和 Execute 方法。
using System;
using Microsoft.SqlServer.Dts.Runtime;
namespace Microsoft.SqlServer.Dts.Samples
{
class Program
{
static void Main(string[] args)
{
Package p = new Package();
MyEventsClass eventsClass = new MyEventsClass();
p.Validate(null, null, eventsClass, null);
p.Execute(null, null, eventsClass, null, null);
Console.Read();
}
}
class MyEventsClass : DefaultEvents
{
public override void OnPreExecute(Executable exec, ref bool fireAgain)
{
// TODO: Add custom code to handle the event.
Console.WriteLine("The PreExecute event of the " +
exec.ToString() + " has been raised.");
}
}
}
Imports Microsoft.SqlServer.Dts.Runtime
Module Module1
Sub Main()
Dim p As Package = New Package()
Dim eventsClass As MyEventsClass = New MyEventsClass()
p.Validate(Nothing, Nothing, eventsClass, Nothing)
p.Execute(Nothing, Nothing, eventsClass, Nothing, Nothing)
Console.Read()
End Sub
End Module
Class MyEventsClass
Inherits DefaultEvents
Public Overrides Sub OnPreExecute(ByVal exec As Executable, ByRef fireAgain As Boolean)
' TODO: Add custom code to handle the event.
Console.WriteLine("The PreExecute event of the " & _
exec.ToString() & " has been raised.")
End Sub
End Class
建立 DtsEventHandler 物件
執行階段引擎會透過 DtsEventHandler 物件提供功能強大且彈性高的事件處理和通知系統。這些物件可讓您在事件處理常式內設計完整工作流程，只有當此事件處理常式所屬的事件發生時，才會執行這些工作流程。DtsEventHandler 物件是一個容器，當引發其父物件上的對應事件時會執行此物件。此架構可讓您建立隔離的工作流程，執行這些工作流程是為了回應容器上所發生的事件。因為 DtsEventHandler 物件是同步的，所以要等到附加至此事件的事件處理常式傳回之後，才會繼續執行。
下列程式碼示範如何建立 DtsEventHandler 物件。此程式碼會將 FileSystemTask 加入至此封裝的 Executables 集合，然後為此工作的 OnError 事件建立 DtsEventHandler 物件。FileSystemTask 會加入至事件處理常式中，當第一個 FileSystemTask 發生 OnError 事件時就會執行此事件處理常式。這個範例假設您有一個名為 C:\Windows\Temp\DemoFile.txt 的檔案以供測試。第一次執行此範例時，表示順利複製此檔案而且未呼叫此事件處理常式。當您第二次執行此範例時，表示第一個 FileSystemTask 複製檔案失敗 (因為 OverwriteDestinationFile 的值是 false)、已呼叫此事件處理常式、第二個 FileSystemTask 偵測到來源檔案，而且因為發生錯誤而導致封裝報表失敗。
範例
using System;
using System.IO;
using Microsoft.SqlServer.Dts.Runtime;
using Microsoft.SqlServer.Dts.Tasks.FileSystemTask;
namespace Microsoft.SqlServer.Dts.Samples
{
class Program
{
static void Main(string[] args)
{
string f = "DemoFile.txt";
Executable e;
TaskHost th;
FileSystemTask fst;
Package p = new Package();
p.Variables.Add("sourceFile", true, String.Empty,
@"C:\Windows\Temp\" + f);
p.Variables.Add("destinationFile", true, String.Empty,
Path.Combine(Directory.GetCurrentDirectory(), f));
// Create a first File System task and add it to the package.
// This task tries to copy a file from one folder to another.
e = p.Executables.Add("STOCK:FileSystemTask");
th = e as TaskHost;
th.Name = "FileSystemTask1";
fst = th.InnerObject as FileSystemTask;
fst.Operation = DTSFileSystemOperation.CopyFile;
fst.OverwriteDestinationFile = false;
fst.Source = "sourceFile";
fst.IsSourcePathVariable = true;
fst.Destination = "destinationFile";
fst.IsDestinationPathVariable = true;
// Add an event handler for the FileSystemTask's OnError event.
DtsEventHandler ehOnError = (DtsEventHandler)th.EventHandlers.Add("OnError");
// Create a second File System task and add it to the event handler.
// This task deletes the source file if the event handler is called.
e = ehOnError.Executables.Add("STOCK:FileSystemTask");
th = e as TaskHost;
th.Name = "FileSystemTask2";
fst = th.InnerObject as FileSystemTask;
fst.Operation = DTSFileSystemOperation.DeleteFile;
fst.Source = "sourceFile";
fst.IsSourcePathVariable = true;
DTSExecResult vr = p.Validate(null, null, null, null);
Console.WriteLine("ValidationResult = " + vr.ToString());
if (vr == DTSExecResult.Success)
{
DTSExecResult er = p.Execute(null, null, null, null, null);
Console.WriteLine("ExecutionResult = " + er.ToString());
if (er == DTSExecResult.Failure)
if (!File.Exists(@"C:\Windows\Temp\" + f))
Console.WriteLine("Source file has been deleted by the event handler.");
}
Console.Read();
}
}
}
Imports System.IO
Imports Microsoft.SqlServer.Dts.Runtime
Imports Microsoft.SqlServer.Dts.Tasks.FileSystemTask
Module Module1
Sub Main()
Dim f As String = "DemoFile.txt"
Dim e As Executable
Dim th As TaskHost
Dim fst As FileSystemTask
Dim p As Package = New Package()
p.Variables.Add("sourceFile", True, String.Empty, _
"C:\Windows\Temp\" & f)
p.Variables.Add("destinationFile", True, String.Empty, _
Path.Combine(Directory.GetCurrentDirectory(), f))
' Create a first File System task and add it to the package.
' This task tries to copy a file from one folder to another.
e = p.Executables.Add("STOCK:FileSystemTask")
th = CType(e, TaskHost)
th.Name = "FileSystemTask1"
fst = CType(th.InnerObject, FileSystemTask)
fst.Operation = DTSFileSystemOperation.CopyFile
fst.OverwriteDestinationFile = False
fst.Source = "sourceFile"
fst.IsSourcePathVariable = True
fst.Destination = "destinationFile"
fst.IsDestinationPathVariable = True
' Add an event handler for the FileSystemTask's OnError event.
Dim ehOnError As DtsEventHandler = CType(th.EventHandlers.Add("OnError"), DtsEventHandler)
' Create a second File System task and add it to the event handler.
' This task deletes the source file if the event handler is called.
e = ehOnError.Executables.Add("STOCK:FileSystemTask")
th = CType(e, TaskHost)
th.Name = "FileSystemTask1"
fst = CType(th.InnerObject, FileSystemTask)
fst.Operation = DTSFileSystemOperation.DeleteFile
fst.Source = "sourceFile"
fst.IsSourcePathVariable = True
Dim vr As DTSExecResult = p.Validate(Nothing, Nothing, Nothing, Nothing)
Console.WriteLine("ValidationResult = " + vr.ToString())
If vr = DTSExecResult.Success Then
Dim er As DTSExecResult = p.Execute(Nothing, Nothing, Nothing, Nothing, Nothing)
Console.WriteLine("ExecutionResult = " + er.ToString())
If er = DTSExecResult.Failure Then
If Not File.Exists("C:\Windows\Temp\" + f) Then
Console.WriteLine("Source file has been deleted by the event handler.")
End If
End If
End If
Console.Read()
End Sub
End Module
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