Introduction
Have you ever wished you code enable or disable a network connection through code? If so, here you go!
Background
A few weeks ago, someone posted a question on the newsgroups about toggling their network connection on and off. I figured the solution relied someplace in the Windows APIs, so I pulled up MSDN and did a little research, but never found a solution. Fortunately, another poster (who researches better than I) posted a link to some VBScript that would do what the poster asked. I had wanted to convert the file to VB.NET, but since I didn't have a reason for the class, I never got around to it.
But you see, yesterday, I published my first article here on CodeProject, and immediately started searching for something else I could publish an article on. This (as you've probably guessed) brought that old post back to mind. I ran through the Google archives until I found the thread, and opened up the link and got to work.
Giving Credit Where Credit is Due
As mentioned previously, this project is mainly a conversion of a VBScript file. This file was published in an article for MCP Mag by Chris Brooke, titled "Controlling Network Connections". The link can be found here: http://mcpmag.com/columns/article.asp?EditorialsID=619.
The Basics
By no means do I understand the internal tracking system Windows uses for stuff like this. The referenced article above probably does a better job of explaining the technical aspects, but I'll explain it in my own words.
From what I gather, there is a folder that manages both the Local Area and wireless connections. Both of these folders are located in the Network Connections folder, which is in turn located in the Control Panel folder. So what this class does is navigate to the specific folder, grabs the enable or disable verb (something like a command I guess), and then calls its DoIt() method which tells the verb to either enable or disable the connection.
And Now Some Code
Prerequisites
For this code to work, you need to add a reference to the Shell32 DLL. This is normally located at C:\Windows\System32\shell32.dll.
The Properties
The original VBScript file used variables to store the reference and then assigned and validated the values in some in-line code. I decided this was better left to readonly properties; after all, why not encapsulate what you can?
First up is the Control Panel folder. This is probably the simplest one to get; you simple instantiate a shell32.Shell object and use its Namespace method to get the Control Panel folder.
Private Shared ReadOnly Property ControlPanelFolder() As Shell32.Folder
Get
Dim shell As New Shell32.Shell()
Return shell.NameSpace(3)
End Get
End Property
Next up is the Network Connections folder. This one is found by looping through the items in the Control Panel folder until you find the correct folder (by checking the Name property).
Note that I throw a custom exception if no folder is found. I'll only include the code for this and the other custom exceptions in the complete code, they are more for the name than anything. Also, I don't have any code that actually catches these exceptions; since everyone has their own error handling strategies, I figured I'd leave this part to you.
Private Shared ReadOnly Property NetworkFolder() As Shell32.Folder
Get
Dim retVal As Shell32.Folder = Nothing
For Each fi As Shell32.FolderItem In ControlPanelFolder.Items
If fi.Name = "Network Connections" Then
retVal = fi.GetFolder()
End If
Next
If retVal Is Nothing Then
Throw New NetworkConnectionsFolderNotFoundException()
Else
Return retVal
End If
End Get
End Property
Finally are the properties for the Local Area and wireless connections. Again, these just loop through the Network Connections folder and get the appropriate folder item based on name.
Private Shared ReadOnly Property LocalAreaConnectionFolderItem() As Shell32.FolderItem
Get
Dim retVal As Shell32.FolderItem = Nothing
For Each folderItem As Shell32.FolderItem In NetworkFolder.Items
Console.WriteLine(folderItem.Name)
If InStr(folderItem.Name.ToLower(), _
"Local Area Connection".ToLower()) Then
retVal = folderItem
Exit For
End If
Next
If retVal Is Nothing Then
Throw New LocalAreaConnectionFolderItemNotFoundException()
Else
Return retVal
End If
End Get
End Property
Private Shared ReadOnly Property WirelessConnectionFolderItem() As Shell32.FolderItem
Get
Dim retVal As Shell32.FolderItem = Nothing
For Each folderItem As Shell32.FolderItem In NetworkFolder.Items
Console.WriteLine(folderItem.Name)
If InStr(folderItem.Name.ToLower(), _
"Wireless Network Connection".ToLower()) Then
retVal = folderItem
Exit For
End If
Next
If retVal Is Nothing Then
Throw New WirelessConnectionFolderItemNotFoundException()
Else
Return retVal
End If
End Get
End Property
The Methods
This part is pretty simple. The method starts a loop that runs though the available verbs (commands?) in the appropriate folder item (Local Area or wireless) and then executes the verb. I use OrElse in the If Then test because the Enable and Disable verbs are mutually exclusive, as the connection can't be both enabled and disabled (disenabled?). Finally, I throw in a Thread.Sleep(1000) just to make sure the verb have time to activate. I tested the code; without this call, the call to enable the connection was ignored about 50% of the time. This was using a console app though, so it's possible that the verb reference was getting destroyed before it even had time to do anything. Please experiment with this and let me know what you find - as I hate to "pause" an app when it's not needed.
Public Shared Sub ToggleWirelessConnection()
For Each verb As Shell32.FolderItemVerb In WirelessConnectionFolderItem.Verbs
If verb.Name = "En&able" OrElse verb.Name = "Disa&ble" Then
verb.DoIt()
Exit For
End If
Next
Threading.Thread.Sleep(1000)
End Sub
Public Shared Sub ToggleLocalAreaConnection()
For Each verb As Shell32.FolderItemVerb In LocalAreaConnectionFolderItem.Verbs
If verb.Name = "En&able" OrElse verb.Name = "Disa&ble" Then
verb.DoIt()
Exit For
End If
Next
Threading.Thread.Sleep(1000)
End Sub
Using the Code
I marked all the methods as Shared so using this code is incredibly simple. Assuming you have added the reference to the Shell32 DLL, all you need to do is:
ToggleNetworkConnection.ToggleLocalAreaConnection()
ToggleNetworkConnection.ToggleWirelessConnection()
The Entire Code
Since I know a lot of people don't want to download a code file for a quick look-see, I figured I'd include this:
Public Class ToggleNetworkConnection
#Region "Public Methods"
Public Shared Sub ToggleWirelessConnection()
For Each verb As Shell32.FolderItemVerb In WirelessConnectionFolderItem.Verbs
If verb.Name = "En&able" OrElse verb.Name = "Disa&ble" Then
verb.DoIt()
Exit For
End If
Next
Threading.Thread.Sleep(1000)
End Sub
Public Shared Sub ToggleLocalAreaConnection()
For Each verb As Shell32.FolderItemVerb In LocalAreaConnectionFolderItem.Verbs
If verb.Name = "En&able" OrElse verb.Name = "Disa&ble" Then
verb.DoIt()
Exit For
End If
Next
Threading.Thread.Sleep(1000)
End Sub
#End Region
#Region "Properties"
Private Shared ReadOnly Property ControlPanelFolder() As Shell32.Folder
Get
Dim shell As New Shell32.Shell()
Return shell.NameSpace(3)
End Get
End Property
Private Shared ReadOnly Property NetworkFolder() As Shell32.Folder
Get
Dim retVal As Shell32.Folder = Nothing
For Each fi As Shell32.FolderItem In ControlPanelFolder.Items
If fi.Name = "Network Connections" Then
retVal = fi.GetFolder()
End If
Next
If retVal Is Nothing Then
Throw New NetworkConnectionsFolderNotFoundException()
Else
Return retVal
End If
End Get
End Property
Private Shared ReadOnly Property LocalAreaConnectionFolderItem() As Shell32.FolderItem
Get
Dim retVal As Shell32.FolderItem = Nothing
For Each folderItem As Shell32.FolderItem In NetworkFolder.Items
Console.WriteLine(folderItem.Name)
If InStr(folderItem.Name.ToLower(), "Local Area Connection".ToLower()) Then
retVal = folderItem
Exit For
End If
Next
If retVal Is Nothing Then
Throw New LocalAreaConnectionFolderItemNotFoundException()
Else
Return retVal
End If
End Get
End Property
Private Shared ReadOnly Property WirelessConnectionFolderItem() As Shell32.FolderItem
Get
Dim retVal As Shell32.FolderItem = Nothing
For Each folderItem As Shell32.FolderItem In NetworkFolder.Items
Console.WriteLine(folderItem.Name)
If InStr(folderItem.Name.ToLower(), _
"Wireless Network Connection".ToLower()) Then
retVal = folderItem
Exit For
End If
Next
If retVal Is Nothing Then
Throw New WirelessConnectionFolderItemNotFoundException()
Else
Return retVal
End If
End Get
End Property
#End Region
#Region "Custom Exceptions"
Public Class NetworkConnectionsFolderNotFoundException
Inherits Exception
Public Overrides ReadOnly Property Message() As String
Get
Return "The Network Connections Folder Could Not Be Found!"
End Get
End Property
End Class
Public Class LocalAreaConnectionFolderItemNotFoundException
Inherits Exception
Public Overrides ReadOnly Property Message() As String
Get
Return "The Local Area Connection Folder Could Not Be Found!"
End Get
End Property
End Class
Public Class WirelessConnectionFolderItemNotFoundException
Inherits Exception
Public Overrides ReadOnly Property Message() As String
Get
Return "The Wireless Connection Folder Could Not Be Found!"
End Get
End Property
End Class
#End Region
End Class
History
- 1/20/2007 - First release.
