///     Hook procedures are installed in chains for particular hook types. <see cref="CallNextHookEx" /> calls the

///     Calling CallNextHookEx is optional, but it is highly recommended; otherwise, other applications that have

///     <see cref="CallNextHookEx" /> unless you absolutely need to prevent the notification from being seen by other

static extern IntPtr CallNextHookEx(IntPtr hhk, int nCode, IntPtr wParam,

static extern IntPtr CallNextHookEx(IntPtr hhk, int nCode, WM wParam, [In]KBDLLHOOKSTRUCT lParam);

static extern IntPtr CallNextHookEx(IntPtr hhk, int nCode, WM wParam, [In]MSLLHOOKSTRUCT lParam);

Private Shared Function CallNextHookEx(ByVal hhk As IntPtr, ByVal nCode As Integer, ByVal wParam As IntPtr, ByVal lParam As IntPtr) As IntPtr

Private Shared Function CallNextHookEx(ByVal hhk As IntPtr, ByVal nCode As Integer, ByVal wParam As WindowsMessages, <[In]()> ByRef lParam As KBDLLHOOKSTRUCT) As IntPtr

Private Shared Function CallNextHookEx(ByVal hhk As IntPtr, ByVal nCode As Integer, ByVal wParam As WindowsMessages, <[In]()> ByRef lParam As MSLLHOOKSTRUCT) As IntPtr

Public Declare Function CallNextHookEx Lib "user32" _

Public Declare Function CallNextHookExKbd Lib "user32" Alias "CallNextHookEx" _

Public Declare Function CallNextHookExMse Lib "user32" Alias "CallNextHookEx" _

Remember to call CallNextHookEx in your callback delegate.

     static extern int CallNextHookEx(IntPtr hhk, int nCode, IntPtr wParam, IntPtr lParam);

        //you need to call CallNextHookEx without further processing

        //and return the value returned by CallNextHookEx

        return CallNextHookEx(IntPtr.Zero, code, wParam, lParam);

    //return the value returned by CallNextHookEx

    return CallNextHookEx(IntPtr.Zero, code, wParam, lParam);

    Friend Shared Function CallNextHookEx(ByVal hhk As intptr, ByVal nCode As Integer, ByVal wParam As intptr, ByVal lParam As intptr) As Integer

        'you need to call CallNextHookEx without further processing

        'and return the value returned by CallNextHookEx

        Return CallNextHookEx(IntPtr.Zero, code, wParam, lParam)    'unt

    'return the value returned by CallNextHookEx

    Return CallNextHookEx(IntPtr.Zero, code, wParam, lParam)

    /// If the Shell procedure handles the WM_COMMAND message, it should not call CallNextHookEx. See the Return Value section for more information.

See SetWindowsHookEx, CallNextHookEx

  return CallNextHookEx(_hookID, nCode, wParam, lParam);

This is named "struct" to be consistent with the Windows API name, but it is defined as a class since it is passed as a pointer (AKA reference) in SetWindowsHookEx and CallNextHookEx. Or it can be defined as a struct and passed with ref (ByRef in VB.NET).