PInvokeStackImbalance using WNetAddConnection2

Hi,

I'm a newbie to the world of VB and VB 2005 Express Edition and I've stumbled across an error I can not resolve myself.

I'm basically trying to map a drive to a remote server via Windows API. User credentials are passed via a simple form. The script falls down when calling WNetAddConnection2 i.e.

returnValue = (WNetAddConnection2(NetResource, Username, password, CONNECT_UPDATE_PROFILE) = 0)

Error Message: Message: A call to PInvoke function 'ReconnectCassPrinters!ReconnectCassPrinters.Form1::WNetAddConnection2' has unbalanced the stack. This is likely because the managed PInvoke signature does not match the unmanaged target signature. Check that the calling convention and parameters of the PInvoke signature match the target unmanaged signature.

The signitaure has been declared as follows:

Private Declare Function WNetAddConnection2 Lib "mpr.dll" Alias "WNetAddConnection2A" _ (ByVal lpNetResource As NETCONNECT, ByVal lpPassword As String, ByVal lpUserName As String, _
ByVal dwFlags As Long) As Long

No one else seems to have reported such an error so I'm certain i've overlooked something simple.

Any help would be much appreciated. The code has been appended below.

Thanks in advance.

Marcus.

Code

Option Explicit On

Public Structure NETCONNECT
Public dwScope As Long
Public dwType As Long
Public dwDisplayType As Long
Public dwUsage As Long
Public lpLocalName As String
Public lpRemoteName As String
Public lpComment As String
Public lpProvider As String
End Structure

Public Class Form1

Private Const CONNECT_UPDATE_PROFILE = &H1&
Public Const RESOURCETYPE_DISK = &H1
Public Const RESOURCETYPE_PRINT = &H2
Public Const RESOURCETYPE_ANY = &H0
Public Const RESOURCE_CONNECTED = &H1
Public Const RESOURCE_REMEMBERED = &H3
Public Const RESOURCE_GLOBALNET = &H2
Public Const RESOURCEDISPLAYTYPE_DOMAIN = &H1
Public Const RESOURCEDISPLAYTYPE_GENERIC = &H0
Public Const RESOURCEDISPLAYTYPE_SERVER = &H2
Public Const RESOURCEDISPLAYTYPE_SHARE = &H3
Public Const RESOURCEUSAGE_CONNECTABLE = &H1
Public Const RESOURCEUSAGE_CONTAINER = &H2
' Error Constants:
Public Const ERROR_ACCESS_DENIED = 5&
Public Const ERROR_ALREADY_ASSIGNED = 85&
Public Const ERROR_BAD_DEV_TYPE = 66&
Public Const ERROR_BAD_DEVICE = 1200&
Public Const ERROR_BAD_NET_NAME = 67&
Public Const ERROR_BAD_PROFILE = 1206&
Public Const ERROR_BAD_PROVIDER = 1204&
Public Const ERROR_BUSY = 170&
Public Const ERROR_CANCELLED = 1223&
Public Const ERROR_CANNOT_OPEN_PROFILE = 1205&
Public Const ERROR_DEVICE_ALREADY_REMEMBERED = 1202&
Public Const ERROR_EXTENDED_ERROR = 1208&
Public Const ERROR_INVALID_PASSWORD = 86&
Public Const ERROR_NO_NET_OR_BAD_PATH = 1203&

Private Declare Function WNetAddConnection2 Lib "mpr.dll" Alias "WNetAddConnection2A" _
(ByVal lpNetResource As NETCONNECT, ByVal lpPassword As String, ByVal lpUserName As String, _
ByVal dwFlags As Long) As Long

Private Sub btnConnect_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnConnect.Click

Dim username As String
Dim password As String

username = txtUsername.Text
password = txtPassword.Text

MapDrive("Z:", "\\myserver", username, password)

End Sub

Public Function MapDrive(ByVal LocalDrive As String, _
ByVal RemoteDrive As String, ByVal Username As String, _
ByVal password As String) As Boolean

'Example:
'MapDrive "Q:", "\\RemoteMachine\RemoteDirectory", _
'"MyLoginName", "MyPassword"

Dim NetResource As NETCONNECT
NetResource.dwScope = RESOURCE_GLOBALNET
NetResource.dwType = RESOURCETYPE_DISK
NetResource.dwDisplayType = RESOURCEDISPLAYTYPE_SHARE
NetResource.dwUsage = RESOURCEUSAGE_CONNECTABLE
NetResource.lpLocalName = LocalDrive
NetResource.lpRemoteName = RemoteDrive
NetResource.lpComment = Nothing
NetResource.lpProvider = Nothing

Dim returnValue As Integer
returnValue = (WNetAddConnection2(NetResource, Username, password, CONNECT_UPDATE_PROFILE) = 0)

If returnValue <> 0 Then
Dim errorM = New System.ComponentModel.Win32Exception(returnValue).Message
MsgBox("Could not connect to share. The server said this: " & vbNewLine & vbNewLine & "(Error " & returnValue & ") " & errorM)
End If

End Function

End Class