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Hide Open/Save FileDialog toolbarbuttons

Posted on 2009-12-22
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Last Modified: 2013-12-17
I am trying to modify the Save/Load FileDialog to fit my own needs. To this end I have been trying to work with memory hooks. So far I have been able to install a keyboard hook which prevents certain key combinations from being executed.

My next step is to try and handle the toolbarbuttons on the FileDialog. I want to be able to make them visible if I desire so. To achieve this goal I have also tried to get a hook to the toolbar, but somehow I just don't seem to get it to work.
The HideToolbarButtons Sub contains the code that should be hiding the correct toolbarbutton, but when I run the project it is still visible in the dialog. I am not sure what is going wrong here.
Imports System.Text
Imports System.Text.Encoding
Imports System.Drawing
Imports System.Collections
Imports System.ComponentModel
Imports System.Windows.Forms
Imports System.Data
Imports System.Runtime.InteropServices

Public Class LCITDialog
    Inherits Component

#Region "Fields"

    Protected Encodings As System.Text.Encoding() = New System.Text.Encoding() {ASCII, UTF8, Unicode, UTF7, UTF32}

    Private _Filter As String = ""
    Private _DefaultExt As String = ""
    Private _FileName As String = ""
    Private _ActiveScreen As Screen
    Private _ReadOnlyDialog As Boolean

    Public KeyboardHandle As Integer
    Public ToolbarHandle As Integer
#End Region

#Region "Constants"

    Private Const OFN_ENABLEHOOK As Integer = 32
    Private Const OFN_EXPLORER As Integer = 524288
    Private Const OFN_FILEMUSTEXIST As Integer = 4096
    Private Const OFN_HIDEREADONLY As Integer = 4
    Private Const OFN_CREATEPROMPT As Integer = 8192
    Private Const OFN_NOTESTFILECREATE As Integer = 65536
    Private Const OFN_OVERWRITEPROMPT As Integer = 2
    Private Const OFN_PATHMUSTEXIST As Integer = 2048
    Private Const SWP_NOSIZE As Integer = 1
    Private Const SWP_NOMOVE As Integer = 2
    Private Const SWP_NOZORDER As Integer = 4
    Private Const WM_INITDIALOG As Integer = 272
    Private Const WM_DESTROY As Integer = 2
    Private Const WM_USER As Integer = &H400
    Private Const WM_SETFONT As Integer = 48
    Private Const WM_GETFONT As Integer = 49
    Private Const CBS_DROPDOWNLIST As Integer = 3
    Private Const CBS_HASSTRINGS As Integer = 512
    Private Const CB_ADDSTRING As Integer = 323
    Private Const CB_SETCURSEL As Integer = 334
    Private Const CB_GETCURSEL As Integer = 327
    Private Const WS_VISIBLE As UInteger = 268435456
    Private Const WS_CHILD As UInteger = 1073741824
    Private Const WS_TABSTOP As UInteger = 65536
    Private Const CDN_FILEOK As Integer = -606
    Private Const CDN_FIRST As Long = -601
    Private Const CDN_INITDONE As Long = (CDN_FIRST - &H0&)
    Private Const WM_NOTIFY As Integer = 78

    Private Const WH_KEYBOARD_LL As Integer = 13&
    ' Virtual Keys
    Public Const VK_TAB = &H9
    Public Const VK_CONTROL = &H11
    Public Const VK_ESCAPE = &H1B
    Public Const VK_DELETE = &H2E
    ' Low-Level Keyboard Constants
    Private Const HC_ACTION As Integer = 0
    Private Const LLKHF_EXTENDED As Integer = &H1
    Private Const LLKHF_INJECTED As Integer = &H10
    Private Const LLKHF_ALTDOWN As Integer = &H20
    Private Const LLKHF_UP As Integer = &H80
    'Toolbarbutton keys
    Private Const TB_BTN_BACK As Integer = 40971
    Private Const TB_BTN_UPONELEVEL As Integer = 40961
    Private Const TB_BTN_NEWFOLDER As Integer = 40962
    Private Const TB_BTN_VIEWMENU As Integer = 40970
    Private Const TB_SETBUTTONINFO As Integer = (WM_USER + 66)
    Private Const TBIF_IMAGE As Integer = &H1
    Private Const TBIF_TEXT As Integer = &H2
    Private Const TBIF_STATE As Integer = &H4
    Private Const TBIF_STYLE As Integer = &H8
    Private Const TBIF_LPARAM As Integer = &H10
    Private Const TBIF_COMMAND As Integer = &H20
    Private Const TBIF_SIZE As Integer = &H40
    Private Const TBSTATE_CHECKED As Integer = &H1
    Private Const TBSTATE_PRESSED As Integer = &H2
    Private Const TBSTATE_ENABLED As Integer = &H4
    Private Const TBSTATE_HIDDEN As Integer = &H8
    Private Const TBSTATE_INDETERMINATE As Integer = &H10
    Private Const TBSTATE_WRAP As Integer = &H20
    Private Const TBSTATE_ELLIPSES As Integer = &H40
    Private Const TBSTATE_MARKED As Integer = &H80

#End Region

#Region "Properties"

    Public Property DefaultExt() As String
        Get
            Return _DefaultExt
        End Get
        Set(ByVal value As String)
            _DefaultExt = value
        End Set
    End Property

    Public Property Filter() As String
        Get
            Return _Filter
        End Get
        Set(ByVal value As String)
            _Filter = value
        End Set
    End Property

    Public Property FileName() As String
        Get
            Return _FileName
        End Get
        Set(ByVal value As String)
            _FileName = value
        End Set
    End Property

    Public Property ReadOnlyDialog() As Boolean
        Get
            Return _ReadOnlyDialog
        End Get
        Set(ByVal value As Boolean)
            _ReadOnlyDialog = value
        End Set
    End Property
#End Region

#Region "Methods"

    <DllImport("Comdlg32.dll", CharSet:=CharSet.Auto, SetLastError:=True)> _
    Private Shared Function GetSaveFileName(ByRef lpofn As OPENFILENAME) As Boolean
    End Function

    <DllImport("Comdlg32.dll")> _
    Private Shared Function CommDlgExtendedError() As Integer
    End Function

    <DllImport("user32.dll")> _
    Private Shared Function SetWindowPos(ByVal hWnd As Integer, ByVal hWndInsertAfter As Integer, ByVal X As Integer, ByVal Y As Integer, ByVal cx As Integer, ByVal cy As Integer, ByVal uFlags As UInteger) As Boolean
    End Function

    <DllImport("user32.dll")> _
    Private Shared Function GetWindowRect(ByVal hWnd As Integer, ByRef lpRect As RECT) As Boolean
    End Function

    <DllImport("user32.dll")> _
    Private Shared Function GetParent(ByVal hWnd As Integer) As Integer
    End Function

    <DllImport("user32.dll", CharSet:=CharSet.Auto)> _
    Private Shared Function SetWindowText(ByVal hWnd As Integer, ByVal lpString As String) As Boolean
    End Function

    <DllImport("user32.dll")> _
    Private Overloads Shared Function SendMessage(ByVal hWnd As Integer, ByVal Msg As Integer, ByVal wParam As Integer, ByVal lParam As Integer) As Integer
    End Function

    <DllImport("user32.dll", CharSet:=CharSet.Auto)> _
    Private Overloads Shared Function SendMessage(ByVal hWnd As Integer, ByVal Msg As Integer, ByVal wParam As Integer, ByVal lParam As String) As Integer
    End Function

    <DllImport("user32.dll")> _
    Private Shared Function DestroyWindow(ByVal hwnd As Integer) As Boolean
    End Function

    <DllImport("user32.dll", CharSet:=CharSet.Auto)> _
    Private Shared Function GetDlgItem(ByVal hDlg As Integer, ByVal nIDDlgItem As Integer) As Integer
    End Function

    <DllImport("user32.dll", CharSet:=CharSet.Auto)> _
    Private Shared Function CreateWindowEx(ByVal dwExStyle As Integer, ByVal lpClassName As String, ByVal lpWindowName As String, ByVal dwStyle As UInteger, ByVal x As Integer, ByVal y As Integer, ByVal nWidth As Integer, ByVal nHeight As Integer, ByVal hWndParent As Integer, ByVal hMenu As Integer, ByVal hInstance As Integer, ByVal lpParam As Integer) As Integer
    End Function

    <DllImport("user32.dll")> _
    Private Shared Function ScreenToClient(ByVal hWnd As Integer, ByRef lpPoint As POINT) As Boolean
    End Function

    <DllImport("user32.dll", EntryPoint:="SetWindowsHookExA")> _
    Private Shared Function SetWindowsHookEx(ByVal idHook As Integer, ByVal lpfn As KeyboardHookDelegate, ByVal hmod As Integer, ByVal dwThreadId As Integer) As Integer
    End Function

    <DllImport("user32.dll")> _
    Private Shared Function GetAsyncKeyState(ByVal vKey As Integer) As Integer
    End Function

    <DllImport("user32.dll")> _
    Private Shared Function CallNextHookEx(ByVal hHook As Integer, ByVal nCode As Integer, ByVal wParam As Integer, ByVal lParam As KBDLLHOOKSTRUCT) As Integer
    End Function

    <DllImport("user32.dll")> _
    Private Shared Function UnhookWindowsHookEx(ByVal hHook As Integer) As Integer
    End Function

    <DllImport("kernel32.dll", CharSet:=CharSet.Auto, SetLastError:=True)> _
    Private Shared Function GetModuleHandle(ByVal lpModuleHandle As String) As Integer
    End Function

    <DllImport("user32.dll", EntryPoint:="FindWindowExA", CallingConvention:=CallingConvention.StdCall, CharSet:=CharSet.Ansi)> _
    Private Shared Function FindWindowEx(ByVal hwndParent As UInteger, ByVal hwndChildAfter As UInteger, ByVal lpszClass As String, ByVal lpszWindow As String) As UInteger
    End Function

    Private Function HookProc(ByVal hdlg As Integer, ByVal msg As Integer, ByVal wParam As Integer, ByVal lParam As Integer) As Integer
        Select Case (msg)
            Case WM_INITDIALOG
                'we need to centre the dialog
                Dim sr As Rectangle = _ActiveScreen.Bounds
                Dim cr As RECT = New RECT
                Dim parent As Integer = GetParent(hdlg)
                GetWindowRect(parent, cr)
                Dim x As Integer = CInt((sr.Right + (sr.Left - (cr.Right - cr.Left))) / 2)
                Dim y As Integer = CInt((sr.Bottom + (sr.Top - (cr.Bottom - cr.Top))) / 2)
                SetWindowPos(parent, 0, x, y, (cr.Right - cr.Left), ((cr.Bottom - cr.Top) + 32), SWP_NOZORDER)

                ToolbarHandle = FindWindowEx(parent, 0, "ToolbarWindow32", 0)
            Case WM_DESTROY
                UnhookKeyboard()

            Case WM_NOTIFY
                'We need to intercept the CDN_INITDONE message
                Dim nmhdr As NMHDR = CType(Marshal.PtrToStructure(New IntPtr(lParam), GetType(NMHDR)), NMHDR)

                Select Case nmhdr.Code
                    Case CDN_INITDONE
                        If Me.ReadOnlyDialog Then
                            'If we have a readonly dialog then we need to install a keyboardhook to prevent certain keys from firing
                            HookKeyboard()
                            HideToolbarButtons()
                        End If
                    Case Else

                End Select
        End Select

        Return 0
    End Function

    Public Function ShowDialog() As DialogResult
        'set up the struct and populate it
        Dim ofn As OPENFILENAME = New OPENFILENAME
        ofn.lStructSize = Marshal.SizeOf(ofn)
        ofn.lpstrFilter = (_Filter.Replace("|", Microsoft.VisualBasic.Chr(0)) + Microsoft.VisualBasic.Chr(0))
        ofn.lpstrFile = (_FileName + New String(Microsoft.VisualBasic.Chr(32), 512))
        ofn.nMaxFile = ofn.lpstrFile.Length
        ofn.lpstrFileTitle = (System.IO.Path.GetFileName(_FileName) + New String(Microsoft.VisualBasic.Chr(32), 512))
        ofn.nMaxFileTitle = ofn.lpstrFileTitle.Length
        ofn.lpstrTitle = "Save test"
        ofn.lpstrDefExt = _DefaultExt
        'position the dialog above the active window
        ofn.hwndOwner = Form.ActiveForm.Handle
        'We need to find out the active screen so the dialog box is centred on the correct display
        _ActiveScreen = Screen.FromControl(Form.ActiveForm)
        'set up some sensible flags
        ofn.Flags = (OFN_EXPLORER _
                          Or (OFN_PATHMUSTEXIST _
                          Or (OFN_NOTESTFILECREATE _
                          Or (OFN_ENABLEHOOK _
                          Or (OFN_HIDEREADONLY Or OFN_OVERWRITEPROMPT)))))
        'This is where the hook is set.
        ofn.lpfnHook = New OFNHookProcDelegate(AddressOf HookProc)
        'if we're running on Windows 98/ME then the struct is smaller
        If (System.Environment.OSVersion.Platform <> PlatformID.Win32NT) Then
            ofn.lStructSize = (ofn.lStructSize - 12)
        End If
        'show the dialog
        If Not GetSaveFileName(ofn) Then
            Dim ret As Integer = CommDlgExtendedError()
            If (ret <> 0) Then
                Throw New ApplicationException(("Couldn't show file open dialog - " + ret.ToString))
            End If
            Return DialogResult.Cancel
        End If

        'Birb-start
        Dim oldFilename As String = _FileName
        _FileName = ofn.lpstrFile
        Dim cancelCheck As New CancelEventArgs()
        RaiseEvent FileOK(Me, cancelCheck)
        If cancelCheck.Cancel Then
            _FileName = oldFilename 'restore filename since dialog was canceled
            Return DialogResult.Cancel
        Else
            Return DialogResult.OK
        End If
        'Birb-end
    End Function

    Public Delegate Function KeyboardHookDelegate(ByVal Code As Integer, ByVal wParam As Integer, ByRef lParam As KBDLLHOOKSTRUCT) As Integer

    <MarshalAs(UnmanagedType.FunctionPtr)> _
    Private callback As KeyboardHookDelegate

    Public Sub HookKeyboard()
        callback = New KeyboardHookDelegate(AddressOf KeyboardCallback)

        Using curProcess As Process = Process.GetCurrentProcess
            Using curModule As ProcessModule = curProcess.MainModule
                KeyboardHandle = SetWindowsHookEx( _
                  WH_KEYBOARD_LL, callback, _
                  GetModuleHandle(curModule.ModuleName), 0)
            End Using
        End Using

    End Sub
    Public Function KeyboardCallback(ByVal Code As Integer, _
    ByVal wParam As Integer, _
    ByRef lParam As KBDLLHOOKSTRUCT) As Integer

        If (Code = HC_ACTION) Then

            If (IsHooked(lParam)) Then
                Return 1
            End If

        End If

        Return CallNextHookEx(KeyboardHandle, Code, wParam, lParam)

    End Function
    ' This function blocks as many key combinations as we'd like
    Public Function IsHooked( _
      ByRef Hookstruct As KBDLLHOOKSTRUCT) As Boolean

        If Hookstruct.vkCode = VK_DELETE Then
            Return True
        End If

        Return False
    End Function

    Public Sub UnhookKeyboard()
        If (KeyboardHandle <> 0) Then
            Call UnhookWindowsHookEx(KeyboardHandle)
        End If
    End Sub

    Private Sub HideToolbarButtons()

        Dim tbInfo As New TBBUTTONINFO

        tbInfo.dwMask = TBIF_STATE
        tbInfo.fsState = TBSTATE_HIDDEN Or TBSTATE_INDETERMINATE
        tbInfo.cbSize = Marshal.SizeOf(tbInfo)

        'Initialize unmanaged memory to hold the structure
        Dim point As IntPtr = Marshal.AllocHGlobal(Marshal.SizeOf(tbInfo))
        Marshal.StructureToPtr(tbInfo, point, True)

        SendMessage(ToolbarHandle, TB_SETBUTTONINFO, TB_BTN_NEWFOLDER, CInt(point))
    End Sub

    Public Delegate Function OFNHookProcDelegate(ByVal hdlg As Integer, ByVal msg As Integer, ByVal wParam As Integer, ByVal lParam As Integer) As Integer

#End Region

#Region "Structures"

    <StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Auto)> _
    Private Structure OPENFILENAME
        Public lStructSize As Integer
        Public hwndOwner As IntPtr
        Public hInstance As Integer
        <MarshalAs(UnmanagedType.LPTStr)> _
     Public lpstrFilter As String
        <MarshalAs(UnmanagedType.LPTStr)> _
     Public lpstrCustomFilter As String
        Public nMaxCustFilter As Integer
        Public nFilterIndex As Integer
        <MarshalAs(UnmanagedType.LPTStr)> _
     Public lpstrFile As String
        Public nMaxFile As Integer
        <MarshalAs(UnmanagedType.LPTStr)> _
     Public lpstrFileTitle As String
        Public nMaxFileTitle As Integer
        <MarshalAs(UnmanagedType.LPTStr)> _
     Public lpstrInitialDir As String
        <MarshalAs(UnmanagedType.LPTStr)> _
     Public lpstrTitle As String
        Public Flags As Integer
        Public nFileOffset As Short
        Public nFileExtension As Short
        <MarshalAs(UnmanagedType.LPTStr)> _
     Public lpstrDefExt As String
        Public lCustData As Integer
        Public lpfnHook As OFNHookProcDelegate
        <MarshalAs(UnmanagedType.LPTStr)> _
     Public lpTemplateName As String
        'only if on nt 5.0 or higher
        Public pvReserved As Integer
        Public dwReserved As Integer
        Public FlagsEx As Integer
    End Structure

    Private Structure RECT
        Public Left As Integer
        Public Top As Integer
        Public Right As Integer
        Public Bottom As Integer
    End Structure

    Private Structure POINT
        Public X As Integer
        Public Y As Integer
    End Structure

    Private Structure NMHDR
        Public HwndFrom As Integer
        Public IdFrom As Integer
        Public Code As Integer
    End Structure

    Public Structure KBDLLHOOKSTRUCT
        Public vkCode As Integer
        Public scanCode As Integer
        Public flags As Integer
        Public time As Integer
        Public dwExtraInfo As Integer
    End Structure

    Public Structure TBBUTTONINFO
        Public cbSize As Long
        Public dwMask As Long
        Public idCommand As Long
        Public iImage As Long
        Public fsState As Byte
        Public fsStyle As Byte
        Public cx As Integer
        Public lParam As Long
        'Public pszText As String
        Public cchText As Long
    End Structure

#End Region

#Region "Events"

    Public Event FileOK(ByVal sender As System.Object, ByVal e As System.ComponentModel.CancelEventArgs) 'Birb

#End Region

End Class

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Question by:Labelsoft
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13 Comments
 
LVL 10

Expert Comment

by:anv
ID: 26103713
0
 
LVL 3

Author Comment

by:Labelsoft
ID: 26103857
That article points to the custom places bar, which is on the left side of the dialog. My problem concerns the toolbar on top with the buttons 'Go To Last Folder Visited', 'Up One Level', 'New Folder' and 'View Menu'  buttons on it.
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Author Comment

by:Labelsoft
ID: 26104607
I think that the FindWindowEx call is returning 0 for some reason that I am not able to determine yet.
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LVL 4

Expert Comment

by:me655321
ID: 26104665
Yes it looks like it IS returning 0. In fact it looks like there are no children of your parent window when that function is triggered. Even moving the code to the CDN_INITDONE section doesn't work.
0
 
LVL 3

Author Comment

by:Labelsoft
ID: 26104737
I fixed the FindWindowEx call, but that did not help anything.
0
 
LVL 3

Author Comment

by:Labelsoft
ID: 26104782
I changed ToolbarHandle = FindWindowEx(parent, 0, "ToolbarWindow32", 0) to ToolbarHandle = FindWindowEx(parent, 0, "ToolbarWindow32", "") and that got me a return value. But somehow it seems it isn't a correct one as the buttons remain unaltered.

0
 
LVL 4

Expert Comment

by:me655321
ID: 26104887
On TB_GETBUTTONINFO or TB_SETBUTTONINFO you're getting an error code 1421 which is "Control ID not found" so it looks like it's not finding TB_BTN_NEWFOLDER.
0
 
LVL 3

Author Comment

by:Labelsoft
ID: 26104982
I am pretty sure that the value of TB_BTN_NEWFOLDER is the correct one. That would mean that the pointer to the control somehow isn't correct.
0
 
LVL 4

Expert Comment

by:me655321
ID: 26105054
I think the pointer is correct...when I run a TB_BUTTONCOUNT on it, it returns 4 as it should.

I think the thing to do is try to do a TB_GETBUTTON to see what the IDs in it actually are. You need to define a structure TBBUTTON for that to work and I can't find a VB.Net declaration of it.
0
 
LVL 3

Author Comment

by:Labelsoft
ID: 26105184
I have the following sturcture declared in my program:

Public Structure TBBUTTONINFO
        Public cbSize As Long
        Public dwMask As Long
        Public idCommand As Long
        Public iImage As Long
        Public fsState As Byte
        Public fsStyle As Byte
        Public cx As Integer
        Public lParam As Long
        'Public pszText As String
        Public cchText As Long
    End Structure

Which is used in:

    Private Sub HideToolbarButtons()

        Dim tbInfo As New TBBUTTONINFO

        tbInfo.dwMask = TBIF_STATE
        tbInfo.fsState = TBSTATE_HIDDEN Or TBSTATE_INDETERMINATE
        tbInfo.cbSize = Marshal.SizeOf(tbInfo)

        'Initialize unmanaged memory to hold the structure
        Dim point As IntPtr = Marshal.AllocHGlobal(Marshal.SizeOf(tbInfo))
        Marshal.StructureToPtr(tbInfo, point, True)

        SendMessage(ToolbarHandle, TB_SETBUTTONINFO, TB_BTN_NEWFOLDER, CInt(point))
    End Sub

When the SendMessage is executed all parameters have a value, which makes me think that it should work, but it doesn't.
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Accepted Solution

by:
me655321 earned 2000 total points
ID: 26105204
Ok well I can't figure out why those IDs won't work, but you might try using TB_DELETEBUTTON instead...

Const TB_DELETEBUTTON = WM_USER + 22
SendMessage(ToolbarHandle, TB_DELETEBUTTON, 2, 0)

Where the wparam is the index of the button to remove. So '2' will remove the new folder button.
0
 
LVL 4

Expert Comment

by:me655321
ID: 26105245
By the way, I think your TBBUTTONINFO structure is a vb definition, not VB.Net. The "Long" values should be "Integer". But that's not what's causing the problem.
0
 
LVL 3

Author Comment

by:Labelsoft
ID: 26105318
I think the problem is with:

        Dim point As IntPtr = Marshal.AllocHGlobal(Marshal.SizeOf(tbInfo))
        Marshal.StructureToPtr(tbInfo, point, True)

         SendMessage(ToolbarHandle, TB_SETBUTTONINFO, TB_BTN_NEWFOLDER, CInt(point))

Perhaps the CInt(point)? But I am not sure about that.

Just deleting the button works fine, yet I am still puzzeled why the hiding doesn't work.
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