VB.Net Windows Service 1

[MadMan001]

Hi.

I am programming a VB.Net Windows Service Application. This service uses a file watcher to watch a directory for XML files - then it goes to process the files etc. This is not the problem.

The problem is that to set the file watcher directory path I need to read this from the Registry. I have coded a read registry function that works fine in my other VB.Net applications however when I add it to my WebService it does not return the value of the registry setting it returns an error "Object reference not set to an instance of an object.". I have included the code below and as I say this works in my other n-tier VB.Net Applications - is there any difference in using reading of the registry in a Windows Service Application?

Thanks in advance.

Code:


Private m_strRequestPath As System.String

Protected Overrides Sub OnStart(ByVal args() As String)

'Service OnStart event.
'

Try

'Set Request File Directories
m_strRequestPath = GetDirectory(SpecifyDirectory.eRequestPath)

Catch ex As System.Exception

Throw

End Try

End Sub

Public Function GetDirectory() As System.String

Try

GetDirectory = GetRegistryValue(Microsoft.Win32.RegistryHive.CurrentUser.CurrentUser, _
"Software\VB and VBA Program Settings\WorkCentre\Paths", _
"PolarisAssembly&quot.Trim

GetDirectory &= "XML\REQUEST\"


Return GetDirectory

Catch ex As System.Exception

Throw

Finally

End Try

End Function

Private Function GetRegistryValue(ByVal regHive As Microsoft.Win32.RegistryHive, _
ByVal strKey As System.String, _
ByVal strValueName As System.String _
) As System.String

Dim objParent As Microsoft.Win32.RegistryKey
Dim objSubkey As Microsoft.Win32.RegistryKey
Dim strValue As System.String = ""

Try
'Select case on the registry hive to open the correct registry class
Select Case regHive

Case Microsoft.Win32.RegistryHive.ClassesRoot
objParent = Microsoft.Win32.Registry.ClassesRoot

Case Microsoft.Win32.RegistryHive.CurrentConfig
objParent = Microsoft.Win32.Registry.CurrentConfig

Case Microsoft.Win32.RegistryHive.CurrentUser
objParent = Microsoft.Win32.Registry.CurrentUser

Case Microsoft.Win32.RegistryHive.DynData
objParent = Microsoft.Win32.Registry.DynData

Case Microsoft.Win32.RegistryHive.LocalMachine
objParent = Microsoft.Win32.Registry.LocalMachine

Case Microsoft.Win32.RegistryHive.PerformanceData
objParent = Microsoft.Win32.Registry.PerformanceData

Case Microsoft.Win32.RegistryHive.Users
objParent = Microsoft.Win32.Registry.Users

End Select

'Once the correct class is open try to initialise the
'appropriate key specified by the user
objSubkey = objParent.OpenSubKey(strKey)

'If the key we are looking for is not found then
'the object will not be initialised otherwise it will
If Not objSubkey Is Nothing Then
strValue = (objSubkey.GetValue(strValueName).ToString)
If strValue Is Nothing Then
strValue = ""
End If
End If

Catch ex As System.Exception
Throw

Finally

'If strValue is empty the registry setting is blank or does not exist
If strValue.Trim = "" Then
GetRegistryValue = "ERROR"
Else
GetRegistryValue = strValue.Trim
End If

objSubkey = Nothing
objParent = Nothing

End Try

End Function

 

[UdoScheuvens]

Hi,

I'm facing the exact same problem. Has somebody found a solution meanwhile?

Udo

 

[Dimandja]

The problem is that there is no Current User for that Windows service.

The Windows service is running by default under the Local System account.

Use the Administrative tools to force a Windows Service to run as a particular user.

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[UdoScheuvens]

Yepp! That did it!