Ok, its time for one more tutorial. This times pick is Windows Services. Creating Windows Services is not a big deal using Visual Basic. Just follow few simple steps and you are all set to run and test your first Windows Service.
Windows Services is new name for NT Services you used to develop in previous versions of Visual Studio. This tutorial walks you through how to create and use your Windows Services. This Service writes some text to a text file when stop and start the service. The base idea is taken from MSDN but its more elaborated. You can modify it according to your needs.
Step 1. Create Skeleton of the Service
To create a new Window Service, pick Windows Service option from your Visual Basic Projects, give your service a name, and click OK.
The result look like this. The Wizard adds WebService1.vb class to your project.
Set your ServiceName to your own name so it would be easier to recognize your service during testing OR you can set this property programmatically using this line Me.ServiceName = "mcWinService"
This is the name you will be looking for later :).
The default code of WebService1.cs added by the Wizard looks like here
Imports Microsoft.VisualBasic
Imports System
Imports System.Collections
Imports System.ComponentModel
Imports System.Configuration
Imports System.Data
Imports System.Web.Services
Imports System.Diagnostics
Imports System.ServiceProcess
Imports System.IO
Namespace mcWebService
' using System.Core;
Public Class WinService1 : Inherits System.ServiceProcess.ServiceBase
''' <summary>
''' Required designer variable.
''' </summary>
Private components As System.ComponentModel.Container
Public Sub New()
' This call is required by the WinForms Component Designer.
InitializeComponent()
' TODO: Add any initialization after the InitComponent call
End Sub
' The main entry point for the process
Shared Sub Main()
Dim ServicesToRun As System.ServiceProcess.ServiceBase()
' More than one user Service may run within the same process. To add
' another service to this process, change the following line to
' create a second service object. For example,
' ServicesToRun = New System.ServiceProcess.ServiceBase[] {new WinService1(), new MySecondUserService()};
ServicesToRun = New System.ServiceProcess.ServiceBase() { New WinService1() }
System.ServiceProcess.ServiceBase.Run(ServicesToRun)
End Sub
''' <summary>
''' Required method for Designer support - do not modify
''' the contents of this method with the code editor.
''' </summary>
Private Sub InitializeComponent()
Me.components = New System.ComponentModel.Container ()
'@this.TrayAutoArrange = true;
'@this.TrayLargeIcon = false;
Me.ServiceName = "mcWinService"
End Sub
''' <summary>
''' Set things in motion so your service can do its work.
''' </summary>
Protected Overrides Sub OnStart(ByVal args As String())
' Create a text file C:\temp\mcb.txt
Dim fs As FileStream = New FileStream("c:\temp\mcWindowsService.txt", FileMode.OpenOrCreate, FileAccess.Write)
Dim m_streamWriter As StreamWriter = New StreamWriter(fs)
m_streamWriter.BaseStream.Seek(0, SeekOrigin.End)
m_streamWriter.WriteLine(" mcWindowsService: Service Started " & Constants.vbLf)
m_streamWriter.Flush()
End Sub
''' <summary>
''' Stop this service.
''' </summary>
Protected Overrides Sub OnStop()
' Create a text file C:\temp\mcb.txt
Dim fs As FileStream = New FileStream("c:\temp\mcWindowsService.txt", FileMode.OpenOrCreate, FileAccess.Write)
Dim m_streamWriter As StreamWriter = New StreamWriter(fs)
m_streamWriter.BaseStream.Seek(0, SeekOrigin.End)
m_streamWriter.WriteLine(" mcWindowsService: Service Stopped " & Constants.vbLf)
m_streamWriter.Flush()
End Sub
End Class
End Namespace
Step 2. Add functionality to your service
As you saw WebService1.vb, there are two overridden functions OnStart and OnStop. The OnStart function executes when you start your service and the OnStop function gets execute when you stop a service. I write some text to a text file when you start and stop the service.
protectedoverride Sub OnStart(ByVal args As String())
Dim fs As FileStream = New FileStream("c:\temp\mcWindowsService.txt", FileMode.OpenOrCreate, FileAccess.Write)
Dim m_streamWriter As StreamWriter = New StreamWriter(fs)
m_streamWriter.BaseStream.Seek(0, SeekOrigin.End)
m_streamWriter.WriteLine(" mcWindowsService: Service Started " & Constants.vbLf)
m_streamWriter.Flush()
m_streamWriter.Close()
End Sub
''' <summary>
''' Stop this service.
''' </summary>
Protected Overrides Sub OnStop()
Dim fs As FileStream = New FileStream("c:\temp\mcWindowsService.txt", FileMode.OpenOrCreate, FileAccess.Write)
Dim m_streamWriter As StreamWriter = New StreamWriter(fs)
m_streamWriter.BaseStream.Seek(0, SeekOrigin.End)
m_streamWriter.WriteLine(" mcWindowsService: Service Stopped " & Constants.vbLf)
m_streamWriter.Flush()
m_streamWriter.Close()
End Sub
Step 3: Install and Run the Service
Build of this application makes one exe, mcWinService.exe. You need to call installutil to register this service from command line.
installutil C:\mcWebService\bin\Debug\mcWebService.exe
You use /u option to uninstall the service.
installutil /u C:\mcWebService\bin\Debug\mcWebService.exe
Run the application
Step 4: Start and Stop the Service
You need to go to the Computer Management to Start to start and stop the service. You can use Manage menu item by right clicking on My Computer.
Under Services and Applications, you will see the service mcWinService. Start and Stop menu item starts and stops the service.
Step 5: Test the Service
Go to your temp directory and see if text file is there with contents or not.
That's it.
References: