FIX: TreeView Tooltips Do Not Appear on Windows NT (241097)

MORE INFORMATION

On all service packs of Windows NT 4.0, the TreeView tooltip windows are created as Unicode windows, even if the TreeView is an ANSI window. Unicode tooltip messages are translated to ANSI, and visa versa. But on Windows 2000, ANSI TreeViews are created with ANSI tooltip windows, and Unicode TreeViews are created with Unicode tooltip windows.

NOTE: This workaround is for illustration only, without warranty either expressed or implied, including, but not limited to, the implied warranties of merchantability and/or fitness for a particular purpose.

Steps to Reproduce Problem

NOTE: This code only demonstrates the problem using comctl32.dll version 4.x on Windows NT:

1. Start a new Visual Basic Standard EXE project. Form1 is created by default.
2. On Project menu, choose Components. Select Microsoft Windows Common Controls 5.0 and click OK.
3. Add a CommandButton and TreeView control to Form1. Size the TreeView such that 35 characters of Node Text are not completely displayed.
4. Add the following code to the General Declarations section of Form1:

   Option Explicit
   
   Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" _
                             (ByVal hWnd As Long, ByVal wMsg As Long, _
                              ByVal wParam As Long, lParam As Any) As Long    
   ' treeview definitions
   
   ' messages
   
   Private Const TV_FIRST = &H1100
   Private Const TVM_GETTOOLTIPS = (TV_FIRST + 25)
   
   ' tooltip definitions
   
   Private Type RECT   ' rc
      Left As Long
      Top As Long
      Right As Long
      Bottom As Long
   End Type
   
   Private Type TOOLINFO
      cbSize As Long
      uFlags As TT_Flags
      hWnd As Long
      uId As Long
      RECT As RECT
      hinst As Long
      lpszText As Long   ' if String, must be pre-allocated before retrieval
      lParam As Long
   End Type   ' TOOLINFO
   
   Private Enum TT_Flags
      TTF_IDISHWND = &H1
      TTF_CENTERTIP = &H2
      TTF_RTLREADING = &H4
      TTF_SUBCLASS = &H10
      TTF_TRACK = &H20
      TTF_UNDOCFLAG = &H40
      TTF_ABSOLUTE = &H80
      TTF_TRANSPARENT = &H100
      TTF_DI_SETITEM = &H8000& ' valid only on the TTN_NEEDTEXT callback
   End Enum   ' TT_Flags
   
   ' messages
   
   Private Const WM_USER = &H400
   Private Const TTM_SETTOOLINFOA = (WM_USER + 9)   ' ANSI
   Private Const TTM_ENUMTOOLSA = (WM_USER + 14)   ' ANSI
   
   ' Comctl32.dll version definitions
   
   Private Type DLLVERSIONINFO
      cbSize As Long
      dwMajorVersion As Long
      dwMinorVersion As Long
      dwBuildNumber As Long
      dwPlatformId As Long
   End Type
   
   ' dwPlatformID values
   Private Const DLLVER_PLATFORM_WINDOWS = &H1 ' built for all Windows vers.
   Private Const DLLVER_PLATFORM_NT = &H2      ' built specifically for NT.
   
   Private Declare Function GetComctl32Version Lib "comctl32" _
      Alias "DllGetVersion" (pdvi As DLLVERSIONINFO) As Long
   
   Private Sub Form_Load()
      Dim i As Integer
      Dim dvi As DLLVERSIONINFO
   
      Command1.Caption = "Fix TreeView Tooltips"
   ' Fill up the treeview...
      For i = 1 To 10
         Call TreeView1.Nodes.Add(Text:="item" & i & String$(30, "x"))
      Next
   
   ' Get the version info of Comctl32.dll (will err on only pre
   ' IE3 installations [< v4.70], where this API is not exported)
   
      dvi.cbSize = Len(dvi)
      On Error GoTo Out
      Call GetComctl32Version(dvi)
      On Error GoTo 0
   
   ' Enable the command button only if Comctl32.dll's major
   ' version is 4, and Comctl32.dll is a NT specific build.
      Command1.Enabled = (dvi.dwMajorVersion = 4) And _
                         (dvi.dwPlatformId = DLLVER_PLATFORM_NT)
      Exit Sub
   
   Out:
   ' Since Windows NT 4.0 was not shipped with a version of
   ' Comctl32.dll < 4.70, this should not occur.
      Command1.Enabled = False
   End Sub
   
   Private Sub Command1_Click()
      Dim hwndTT As Long
      Dim ti As TOOLINFO
   
   ' Get the handle of the TreeView's tooltip window
      hwndTT = SendMessage(TreeView1.hWnd, TVM_GETTOOLTIPS, 0, 0)
      If hwndTT Then
   
   ' Initialize the TOOLINFO struct, and get the info for its
   ' first and only tool
         ti.cbSize = Len(ti)
         If SendMessage(hwndTT, TTM_ENUMTOOLSA, 0, ti) Then
            ti.uFlags = TTF_IDISHWND Or TTF_TRANSPARENT Or TTF_UNDOCFLAG
            Call SendMessage(hwndTT, TTM_SETTOOLINFOA, 0, ti) ' &H141
   
            Command1.Enabled = False ' We're all done.
         End If   ' TTM_ENUMTOOLSA
      End If   ' hwndTT
   End Sub

5. Run the Project and place the cursor over a Node item.
6. Now click the CommandButton and repeat the previous step.