Dim hwnd As IntPtr

        SetReaderModeInfo.hwnd = Me.Handle

    Public Shared Function GetScrollPos(ByVal hWnd As IntPtr, ByVal nBar As Integer) As Integer

    Private Shared Function SetScrollPos(ByVal hWnd As IntPtr, ByVal nBar As Integer, ByVal nPos As Integer, ByVal bRedraw As Boolean) As Integer

/// <param name="hwndLock">Handle to the window that owns the drag image.</param>

internal static extern bool ImageList_DragEnter(IntPtr hwndLock, int x, int y);

''' <param name="hwndLock">Handle to the window that owns the drag image.</param>

Friend Shared Function ImageList_DragEnter(hwndLock As IntPtr, x As Integer, y As Integer) As <MarshalAs(UnmanagedType.Bool)> Boolean

/// <param name="hwndLock">Handle to the window that owns the drag image.</param>

internal static extern bool ImageList_DragLeave(IntPtr hwndLock);

''' <param name="hwndLock">Handle to the window that owns the drag image.</param>

Friend Shared Function ImageList_DragLeave(hwndLock As IntPtr) As <MarshalAs(UnmanagedType.Bool)> Boolean

        public IntPtr hwndParent;

        public IntPtr hwndParent;

    public IntPtr hwndOwner;

     Public hwndOwner As IntPtr

   public IntPtr hwnd;

• Desktop handle to the window specified by hwnd. This is returned only if BroadcastSystemMessageEx specifies BSF_RETURNHDESK and BSF_QUERY.

• hwnd

        public IntPtr        hwnd;          // might be NULL (indicating no owner window)

    public IntPtr hwndCombo;

    public IntPtr hwndEdit;

    public IntPtr hwndList;

    hwndCombo As Long

    hwndEdit As Long

    hwndList As Long

   SendMessage(hWnd, WM_COPYDATA, IntPtr.Zero, copyDataBuff);

        public IntPtr hwndParent;

        Public hwndParent As IntPtr

            public IntPtr hwndParent;

    Public hwndParent As IntPtr

    public IntPtr hwndApp;

    Public hwndApp As IntPtr

     IntPtr hWnd;

        public IntPtr hwnd;

        Public hWnd As IntPtr

    public IntPtr hwnd;

    Public hwnd As IntPtr

    public IntPtr        hwndActive;

    public IntPtr        hwndFocus;

    public IntPtr        hwndCapture;

    public IntPtr        hwndMenuOwner;

    public IntPtr        hwndMoveSize;

    public IntPtr        hwndCaret;

    Public hwndActive As IntPtr

    Public hwndFocus As IntPtr

    Public hwndCapture As IntPtr

    Public hwndMenuOwner As IntPtr

    Public hwndMoveSize As IntPtr

    Public hwndCaret As IntPtr

    public IntPtr hwnd;

    public IntPtr hwnd;

    public IntPtr hwndOwner;

   public IntPtr hwndFrom;

   Public hwndFrom As IntPtr

    /// taskbar status area. The Shell uses hWnd and uID to identify which icon to operate on

    public IntPtr hwnd;

    /// Application-defined identifier of the taskbar icon. The Shell uses hWnd and uID to identify

    /// associated with a single hWnd by assigning each a different uID.

    /// notifications to the window identified in hWnd.

    public IntPtr hWnd;

    Dim hWnd As IntPtr

   public IntPtr hWnd;

    int hwndOwner;

    Public hwndOwner As IntPtr  

   public IntPtr hwndOwner;

    Public hwndOwner As IntPtr

    public IntPtr hwndOwner;        

   public int hwndParent = 0;

        Dim hwnd As IntPtr

        Dim hwnd As IntPtr

        SetReaderModeInfo.hwnd = Me.Handle

        public IntPtr hwndChild;

    public IntPtr hwnd;

     Public hwnd As IntPtr

     hWnd As Long

• Always set hwnd to my main app window (I was using IntPtr.Zero, this might not be required)
An IntPtr is a pointer to a memory location (unmanaged) that adapts to the platform it is running on (64-bit, etc.) UNLIKE a standard int/Integer. You should always use this type for unmanaged calls that require it, even though an int will appear to work on your development machine.
1/13/2008 4:00:13 AM - Damon Carr-72.43.165.29

        public static extern bool GetTitleBarInfo(IntPtr hwnd, ref TITLEBARINFO pti);

   public IntPtr hwnd;

    Public hwnd As IntPtr

   public IntPtr  hwndTrack;

   Public hwndTrack As IntPtr

        public IntPtr hwnd;

        public IntPtr hwndInsertAfter;

        Public hwnd As IntPtr

        Public hwndInsertAfter As IntPtr

      public IntPtr hwndParent;

    credui.hwndParent = this.Handle;

     public IntPtr hwndParent;

LRESULT APIENTRY buttonPlsVisibleProc(HWND hWnd, UINT Msg, WPARAM wParam, LPARAM lParam)

            MessageBox(hWnd, L"Hello bn", NULL, MB_OK);

        //MoveWindow(hWnd, r.right - 28, 6, 24, 24, TRUE);

        //SetBitmap(hWnd, (isPlaylistVisible ? IDB_RESTORE_PRESSED : IDB_CLOSE_PRESSED));

        //MoveWindow(hWnd, r.right - 29, 5, 24, 24, TRUE);

        //SetBitmap(hWnd, (isPlaylistVisible ? IDB_RESTORE_NORMAL : IDB_CLODE_NORMAL));

    return CallWindowProc(buttonPlsVisible_proc, hWnd, Msg, wParam, lParam);

            public const uint GW_HWNDFIRST = 0;

            public const uint GW_HWNDLAST = 1;

            public const uint GW_HWNDNEXT = 2;

            public const uint GW_HWNDPREV = 3;

            public const uint GW_HWNDFIRST = 0;

            public const uint GW_HWNDLAST = 1;

            public const uint GW_HWNDNEXT = 2;

            public const uint GW_HWNDPREV = 3;

    GW_HWNDFIRST = 0

    GW_HWNDLAST = 1

    GW_HWNDNEXT = 2

    GW_HWNDPREV = 3

static readonly int GWL_HWNDPARENT = -8;

Public Const GWL_HWNDPARENT = -8

     GWLP_HWNDPARENT = -8,

public const IntPtr HWND_BROADCAST = new IntPtr(0xffff);

public const IntPtr HWND_TOP       = new IntPtr(0);

public const IntPtr HWND_BOTTOM    = new IntPtr(1);

public const IntPtr HWND_TOPMOST   = new IntPtr(-1);

public const IntPtr HWND_NOTOPMOST = new IntPtr(-2);

public const IntPtr HWND_MESSAGE   = new IntPtr(-3);

Public Const HWND_BROADCAST As Int32 = &HFFFF

Public Const HWND_TOP As Int32       = &H0

Public Const HWND_BOTTOM As Int32    = &H1

Public Const HWND_TOPMOST As Int32   = -&H1

Public Const HWND_NOTOPMOST As Int32 = -&H2

Public Const HWND_MESSAGE As Int32   = -&H3

public static IntPtr HWND_MESSAGE = new IntPtr(-3);

    // (HIMAGELIST)SNDMSG((hwnd), TCM_GETIMAGELIST, 0, 0L)

    // (HIMAGELIST)SNDMSG((hwnd), TCM_SETIMAGELIST, 0, (LPARAM)(UINT)(HIMAGELIST)(himl))

    // (int)SNDMSG((hwnd), TCM_GETITEMCOUNT, 0, 0L)

    // (BOOL)SNDMSG((hwnd), TCM_GETITEM, (WPARAM)(int)iItem, (LPARAM)(TC_ITEM FAR*)(pitem))

    // (BOOL)SNDMSG((hwnd), TCM_SETITEM, (WPARAM)(int)iItem, (LPARAM)(TC_ITEM FAR*)(pitem))

    // (int)SNDMSG((hwnd), TCM_INSERTITEM, (WPARAM)(int)iItem, (LPARAM)(const TC_ITEM FAR*)(pitem))

    // (BOOL)SNDMSG((hwnd), TCM_DELETEITEM, (WPARAM)(int)(i), 0L)

    // (BOOL)SNDMSG((hwnd), TCM_DELETEALLITEMS, 0, 0L)

    // (BOOL)SNDMSG((hwnd), TCM_GETITEMRECT, (WPARAM)(int)(i), (LPARAM)(RECT FAR*)(prc))

    // (int)SNDMSG((hwnd), TCM_GETCURSEL, 0, 0)

    // (int)SNDMSG((hwnd), TCM_SETCURSEL, (WPARAM)i, 0)

    // (int)SNDMSG((hwndTC), TCM_HITTEST, 0, (LPARAM)(TC_HITTESTINFO FAR*)(pinfo))

    // (BOOL)SNDMSG((hwndTC), TCM_SETITEMEXTRA, (WPARAM)(cb), 0L)

    // (int)SNDMSG(hwnd, TCM_ADJUSTRECT, (WPARAM)(BOOL)bLarger, (LPARAM)(RECT FAR *)prc)

    // (DWORD)SNDMSG((hwnd), TCM_SETITEMSIZE, 0, MAKELPARAM(x,y))

    //     (void)SNDMSG((hwnd), TCM_REMOVEIMAGE, i, 0L)

    //     (void)SNDMSG((hwnd), TCM_SETPADDING, 0, MAKELPARAM(cx, cy))

    //     (int)SNDMSG((hwnd), TCM_GETROWCOUNT, 0, 0L)

    // (int)SNDMSG((hwnd), TCM_GETCURFOCUS, 0, 0)

    // SNDMSG((hwnd),TCM_SETCURFOCUS, i, 0)

    //     (int)SNDMSG((hwnd), TCM_SETMINTABWIDTH, 0, x)

    //     (void)SNDMSG((hwnd), TCM_DESELECTALL, fExcludeFocus, 0)

    // (BOOL)SNDMSG((hwnd), TCM_HIGHLIGHTITEM, (WPARAM)i, (LPARAM)MAKELONG (fHighlight, 0))

    //     (DWORD)SNDMSG((hwnd), TCM_SETEXTENDEDSTYLE, 0, dw)

    //     (DWORD)SNDMSG((hwnd), TCM_GETEXTENDEDSTYLE, 0, 0)

    '     (HIMAGELIST)SNDMSG((hwnd), TCM_GETIMAGELIST, 0, 0L)

    '     (HIMAGELIST)SNDMSG((hwnd), TCM_SETIMAGELIST, 0, (LPARAM)(UINT)(HIMAGELIST)(himl))

    '     (int)SNDMSG((hwnd), TCM_GETITEMCOUNT, 0, 0L)

    '     (BOOL)SNDMSG((hwnd), TCM_GETITEM, (WPARAM)(int)iItem, (LPARAM)(TC_ITEM FAR*)(pitem))

    '     (BOOL)SNDMSG((hwnd), TCM_SETITEM, (WPARAM)(int)iItem, (LPARAM)(TC_ITEM FAR*)(pitem))

    '     (int)SNDMSG((hwnd), TCM_INSERTITEM, (WPARAM)(int)iItem, (LPARAM)(const TC_ITEM FAR*)(pitem))

    '     (BOOL)SNDMSG((hwnd), TCM_DELETEITEM, (WPARAM)(int)(i), 0L)

    '     (BOOL)SNDMSG((hwnd), TCM_DELETEALLITEMS, 0, 0L)

    '     (BOOL)SNDMSG((hwnd), TCM_GETITEMRECT, (WPARAM)(int)(i), (LPARAM)(RECT FAR*)(prc))

    '     (int)SNDMSG((hwnd), TCM_GETCURSEL, 0, 0)

    '     (int)SNDMSG((hwnd), TCM_SETCURSEL, (WPARAM)i, 0)

    '     (int)SNDMSG((hwndTC), TCM_HITTEST, 0, (LPARAM)(TC_HITTESTINFO FAR*)(pinfo))

    '     (BOOL)SNDMSG((hwndTC), TCM_SETITEMEXTRA, (WPARAM)(cb), 0L)

    '     (int)SNDMSG(hwnd, TCM_ADJUSTRECT, (WPARAM)(BOOL)bLarger, (LPARAM)(RECT FAR *)prc)

    '     (DWORD)SNDMSG((hwnd), TCM_SETITEMSIZE, 0, MAKELPARAM(x,y))

    '     (void)SNDMSG((hwnd), TCM_REMOVEIMAGE, i, 0L)

    '     (void)SNDMSG((hwnd), TCM_SETPADDING, 0, MAKELPARAM(cx, cy))

    '     (int)SNDMSG((hwnd), TCM_GETROWCOUNT, 0, 0L)

    '     (int)SNDMSG((hwnd), TCM_GETCURFOCUS, 0, 0)

    '     SNDMSG((hwnd),TCM_SETCURFOCUS, i, 0)

    '     (int)SNDMSG((hwnd), TCM_SETMINTABWIDTH, 0, x)

    '     (void)SNDMSG((hwnd), TCM_DESELECTALL, fExcludeFocus, 0)

    '     (BOOL)SNDMSG((hwnd), TCM_HIGHLIGHTITEM, (WPARAM)i, (LPARAM)MAKELONG (fHighlight, 0))

    '     (DWORD)SNDMSG((hwnd), TCM_SETEXTENDEDSTYLE, 0, dw)

    '     (DWORD)SNDMSG((hwnd), TCM_GETEXTENDEDSTYLE, 0, 0)

     if (m.Msg == Win32.WM_ACTIVATE && m.HWnd == f.Handle

        public const int ERROR_HWNDS_HAVE_DIFF_PARENT = 1441;

        public const int OLE_E_INVALIDHWND = (int)(0x8004000F - 0x100000000);

        public const int DRAGDROP_E_INVALIDHWND = (int)(0x80040102 - 0x100000000);

        public const int OLEOBJ_S_INVALIDHWND = 0x00040182;

static extern Int32 mciSendString(string command, StringBuilder buffer, int bufferSize, IntPtr hwndCallback);

Private Shared Function mciSendString(ByVal command As String, ByVal buffer As StringBuilder, ByVal bufferSize As Integer, ByVal hwndCallback As IntPtr) As Integer

Declare Ansi Function mciSendString Lib "winmm.dll" Alias "mciSendStringA" (ByVal command As String, ByRef buffer As StringBuilder, ByVal bufferSize As Integer, ByVal hWndCallback As IntPtr) As Integer

static extern Int32 mciSendString(string command, string buffer, int bufferSize, IntPtr hwndCallback);

     private IntPtr hwndOwner;

//     private UInt32 cMultipleItems; //Unioned with hwndOwner /* if _MULTIPLE, the number of items per channel */

        get { return this.hwndOwner; }

        set { this.hwndOwner = value; }

        get { return (UInt32)this.hwndOwner; }

        set { this.hwndOwner = (IntPtr)value; }

     Dim hWndOwner As IntPtr

private static extern Int32 InternetDial(IntPtr hwndParent, string lpszConnectoid, Int32 dwFlags, ref Int32 lpdwConnection, Int32 dwReserved);

static extern int DocumentProperties(IntPtr hwnd, IntPtr hPrinter, [MarshalAs(UnmanagedType.LPWStr)] string pDeviceName, IntPtr pDevModeOutput, IntPtr pDevModeInput, int fMode);

static extern int DocumentProperties(IntPtr hWnd, IntPtr hPrinter, string pDeviceName, IntPtr pDevModeOutput, IntPtr pDevModeInput, fModes fMode);

    Private Shared Function DocumentProperties(ByVal hwnd As IntPtr, ByVal hPrinter As IntPtr, <MarshalAs(UnmanagedType.LPWStr)> ByVal pDeviceName As String, ByVal pDevModeOutput As IntPtr, ByVal pDevModeInput As IntPtr, ByVal fMode As Integer) As Integer

    pinvokeResult = SendMessageTimeout(HWND_BROADCAST, WM_SETTINGCHANGE, IntPtr.Zero,

    IntPtr HWND_BROADCAST;

        HWND_BROADCAST = new IntPtr(0xffff);

        pinvokeResult = SendMessageTimeout(HWND_BROADCAST, WM_SETTINGCHANGE, IntPtr.Zero,

private static extern void PrintUIEntryW(IntPtr hwnd, IntPtr hinst, string lpszCmdLine, int nCmdShow);

     public IntPtr hwndOwner;

    '  HWND      hwndOwner;

typedef UINT_PTR (CALLBACK *LPOFNHOOKPROC) (HWND,UINT,WPARAM,LPARAM);

     HWND hwndOwner;

    ofn.hwndOwner = NULL;

    '  HWND      hwndOwner;

        _pdex.hwndOwner = m_hParent

    Public hwndOwner As IntPtr

        _pdex.hwndOwner = m_hParent

    Public hwndOwner As IntPtr

    //        HWND hWnd;

    public IntPtr hWnd;

    public IntPtr hWnd;

    Public hWnd As IntPtr

    public IntPtr hWnd;

  myBarData.hWnd = MyBar.Handle;

static extern void DragAcceptFiles(IntPtr hwnd, bool fAccept);

    ByVal hwnd As Long, _

     void AddTab(IntPtr hwnd);

     void DeleteTab(IntPtr hwnd);

     void ActivateTab(IntPtr hwnd);

     void SetActiveAlt(IntPtr hwnd);

     IntPtr hwnd,

     void SetProgressValue(IntPtr hwnd, UInt64 ullCompleted, UInt64 ullTotal);

     void SetProgressState(IntPtr hwnd, TaskbarProgressBarStatus tbpFlags);

     void RegisterTab(IntPtr hwndTab, IntPtr hwndMDI);

     void UnregisterTab(IntPtr hwndTab);

     void SetTabOrder(IntPtr hwndTab, IntPtr hwndInsertBefore);

     void SetTabActive(IntPtr hwndTab, IntPtr hwndInsertBefore, uint dwReserved);

     IntPtr hwnd,

     IntPtr hwnd,

     void ThumbBarSetImageList(IntPtr hwnd, IntPtr himl);

       IntPtr hwnd,

     IntPtr hwnd,

     IntPtr hwnd,

     void SetTabProperties(IntPtr hwndTab, SetTabPropertiesOption stpFlags);

    Sub AddTab(hwnd As IntPtr)

    Sub DeleteTab(hwnd As IntPtr)

    Sub ActivateTab(hwnd As IntPtr)

    Sub SetActiveAlt(hwnd As IntPtr)

    Sub MarkFullscreenWindow(hwnd As IntPtr, <MarshalAs(UnmanagedType.Bool)> fFullscreen As Boolean)

    Sub SetProgressValue(hwnd As IntPtr, ullCompleted As UInt64, ullTotal As UInt64)

    Sub SetProgressState(hwnd As IntPtr, tbpFlags As TaskbarProgressBarStatus)

    Sub RegisterTab(hwndTab As IntPtr, hwndMDI As IntPtr)

    Sub UnregisterTab(hwndTab As IntPtr)

    Sub SetTabOrder(hwndTab As IntPtr, hwndInsertBefore As IntPtr)

    Sub SetTabActive(hwndTab As IntPtr, hwndInsertBefore As IntPtr, dwReserved As UInteger)

    Function ThumbBarAddButtons(hwnd As IntPtr, cButtons As UInteger, <MarshalAs(UnmanagedType.LPArray)> pButtons As ThumbButton()) As HResult

    Function ThumbBarUpdateButtons(hwnd As IntPtr, cButtons As UInteger, <MarshalAs(UnmanagedType.LPArray)> pButtons As ThumbButton()) As HResult

    Sub ThumbBarSetImageList(hwnd As IntPtr, himl As IntPtr)

    Sub SetOverlayIcon(hwnd As IntPtr, hIcon As IntPtr, <MarshalAs(UnmanagedType.LPWStr)> pszDescription As String)

    Sub SetThumbnailTooltip(hwnd As IntPtr, <MarshalAs(UnmanagedType.LPWStr)> pszTip As String)

    Sub SetThumbnailClip(hwnd As IntPtr, prcClip As IntPtr)

    Sub SetTabProperties(hwndTab As IntPtr, stpFlags As SetTabPropertiesOption)

    /// <param name="hWnd"></param>

    void MarkFullscreenWindow([In] IntPtr hWnd, [In] int fFullscreen);