FIX: TreeView Tooltips Do Not Appear on Windows NT

• Microsoft Visual Basic Learning, Professional, and Enterprise Editions for Windows, versions 5.0, 6.0
  on the following platforms: NT

SYMPTOMS

The Node tooltip (item tip) for the TreeView control included in Comctl32.ocx fails to appear when the cursor is over a Node with text obscured by the right border of the TreeView's client window. This problem has only been observed on Windows NT 4.0 when using Comctl32.dll version 4.x. Comctl32.dll version 5.x does not exhibit this behavior under Windows NT 4.0. (Comctl32.ocx is dynamically linked to the currently running version of Comctl32.dll). This problem also does not occur when running on Win95, Win98, or Win2K, nor does it occur using the TreeView control from Mscomctl.ocx.

RESOLUTION

The tooltip window appears correctly after filling in the TOOLINFO struct of the Visual Basic TreeView tooltip window's first and only tool with the TTM_ENUMTOOLS message, setting its uFlags member value to &H141, and setting the tool's info with the TTM_SETTOOLINFO message.

STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. This bug has been fixed in comctl32.dll version 5.xx and later.

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

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.

REFERENCES

For additional information regarding treeview tooltip issues, click the article numbers below to view the articles in the Microsoft Knowledge Base:

Q240924 BUG: TreeView Node Tooltips Flash when Displayed from Modal Form

Q241102 BUG: TreeView Nodes Tooltips Fail to Appear on Usercontrol

Additional query words:

Keywords : kbCmnCtrls kbNTOS400 kbTreeView kbVBp kbVBp500 kbVBp600 kbGrpVB kbDSupport
Version : WINDOWS:5.0,6.0
Platform : WINDOWS
Issue type : kbbug