Hello,

I'm currently trying to port a piece of code from VB6 to VB.net which
enables my application to display balloon tooltips. Unfortunately it
doesn't seem to work. This is the code

    VB:

Public Class clsBalloonTips

    <StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Auto)> _
    Private Structure INITCOMMONCONTROLSEXSTRUCT
        Public dwSize As Int32 'size of this structure
        Public dwICC As Int32 'flags indicating which classes to be
initialized
    End Structure

    <StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Auto)> _
    Private Structure RECT
        Public Left As Int32
        Public Top As Int32
        Public Right As Int32
        Public Bottom As Int32
    End Structure

    Private Structure TOOLINFO
        Public cbSize As Int32
        Public uFlags As Int32
        Public hwnd As Int32
        Public uID As Int32
        Public WinRect As Rect
        Public hInst As Int32
        Public lpszText As String
        Public lParam As Int32
    End Structure

    Private Declare Function CreateWindowEx Lib "user32.dll" Alias _
        "CreateWindowExA" (ByVal dwExStyle As Int32, _
        ByVal lpClassName As String, ByVal lpWindowName As String, _
        ByVal dwStyle As Int32, ByVal x As Int32, ByVal y As Int32, _
        ByVal nWidth As Int32, ByVal nHeight As Int32, _
        ByVal hWndParent As Int32, ByVal hMenu As Int32, _
        ByVal hInstance As Int32, ByVal lpParam As Int32) As Int32
    Private Declare Function SetWindowPos Lib "user32.dll" _
        (ByVal hwnd As Int32, ByVal hWndInsertAfter As Int32, _
        ByVal x As Int32, ByVal y As Int32, ByVal cx As Int32, _
        ByVal cy As Int32, ByVal wFlags As Int32) As Int32
    Private Declare Function InitCommonControlsEx Lib "comctl32.dll" _
        (ByRef TLPINITCOMMONCONTROLSEX As INITCOMMONCONTROLSEXSTRUCT) _
        As Int32
    Private Declare Function DestroyWindow Lib "user32.dll" _
        (ByVal hwnd As Int32) As Int32
    Private Declare Function SendMessage Lib "user32.dll" Alias _
        "SendMessageA" (ByVal hwnd As Int32, ByVal wMsg As Int32, _
        ByVal wParam As Int32, ByVal lParam As TOOLINFO) As Int32
    Private Declare Function GetModuleHandle Lib "kernel32.dll" _
        Alias "GetModuleHandleA" (ByVal lpModuleName As String) As Int32
    Private Declare Function GetLastError Lib "kernel32.dll" () As Int32

    Public Enum TooltipFlagConstants
        ttfAlwaysTip = &H1
        ttfNoPrefix = &H2
        ttfNoAnimate = &H10
        ttfNoFade = &H20
        ttfBalloon = &H40
    End Enum

    Public Enum ToolFlagConstants
        tfCenterTip = &H2
        tfRtlReading = &H4
        tfTrack = &H20
        tfAbsolute = &H80
        tfTransparent = &H100
    End Enum

    Private Const ICC_WIN95_CLASSES As Int32 = &HFF
    Private Const ICC_BAR_CLASSES As Int32 = &H4
    Private Const WS_EX_TOPMOST As Int32 = &H8I
    Private Const TOOLTIPS_CLASS As String = "tooltips_class"
    Private Const WS_POPUP As Int32 = &H80000000
    Private Const CW_USEDEFAULT As Int32 = &H80000000
    Private Const HWND_TOPMOST As Int32 = -1
    Private Const SWP_NOMOVE As Int32 = &H2
    Private Const SWP_NOSIZE As Int32 = &H1
    Private Const SWP_NOACTIVATE As Int32 = &H10
    Private Const TTF_IDISHWND = &H1
    Private Const TTF_SUBCLASS = &H10
    Private Const WM_USER = &H400
      Private Const TTM_ADDTOOL = WM_USER + 50

    Private hWndTT As Int32

    Public Sub New()
    End Sub

    Public Sub Dispose()
        Destroy()
    End Sub

    Public Sub Create(ByRef Frm As Form, ByVal Flags As
TooltipFlagConstants)
        Try
            Dim InitCtrls As INITCOMMONCONTROLSEXSTRUCT

            InitCtrls.dwSize = Len(InitCtrls)
            InitCtrls.dwICC = ICC_WIN95_CLASSES Or ICC_BAR_CLASSES

            Destroy()

            Dim intResult As Int32
            intResult = InitCommonControlsEx(InitCtrls)

            intResult = Frm.Handle.ToInt32
            intResult = GetModuleHandle(Nothing)
                    ' =========== FAILS HERE =============
            hWndTT = CreateWindowEx(WS_EX_TOPMOST, TOOLTIPS_CLASS, "", _
                WS_POPUP Or Flags, CW_USEDEFAULT, CW_USEDEFAULT, _
                CW_USEDEFAULT, CW_USEDEFAULT, Frm.Handle.ToInt32, 0, _
                GetModuleHandle(Nothing), 0)

            intResult = GetLastError()

            SetWindowPos(hWndTT, HWND_TOPMOST, 0, 0, 0, 0, SWP_NOMOVE Or _
                SWP_NOSIZE Or SWP_NOACTIVATE)
        Catch ex As Exception
        End Try
    End Sub

    Public Sub AddTool(ByRef Ctl As Control, _
        ByVal Flags As ToolFlagConstants, Optional ByVal Text As
String= "")
        Try
            Dim Info As TOOLINFO

            If hWndTT = 0 Then Return

            Info.cbSize = Len(Info)
            Info.uFlags = Flags
            If Not (Flags And ToolFlagConstants.tfTrack) Then
                Info.uFlags = Info.uFlags Or TTF_SUBCLASS
            End If
            Info.uFlags = Info.uFlags Or TTF_IDISHWND
            Info.hwnd = Ctl.Parent.Handle.ToInt32
            Info.hInst = 0
            Info.uID = Ctl.Handle.ToInt32 ' Ctl.hwnd
            If Len(Text) > 0 Then
                Info.lpszText = Text
            End If

            SendMessage(hWndTT, TTM_ADDTOOL, 0, Info)
        Catch ex As Exception
        End Try
    End Sub

    Public Sub Destroy()
        If hWndTT <> 0 Then DestroyWindow(hWndTT)
    End Sub
End Class

The class is called like this:

    VB:

Dim cToolTips As New clsToolTips
cToolTips.Create(Me, _
                    clsBalloonTips.TooltipFlagConstants.ttfBalloon Or _
                    clsBalloonTips.TooltipFlagConstants.ttfAlwaysTip)
cToolTips.AddTool(button1, "Hello ya")

I debugged the code and the error occurs at the marked line.
CreateWindow returns 0, GetLastError returns 1407 (class not found). I
suppose passing the class string does not work? How to fix it?

Thanks in advance,

Stefan