C# Signature:

/// <summary>
///     Passes the hook information to the next hook procedure in the current hook chain. A hook procedure can call this
///     function either before or after processing the hook information.
///     <para>
///     See [ https://msdn.microsoft.com/en-us/library/windows/desktop/ms644974%28v=vs.85%29.aspx ] for more
///     information.
///     </para>
/// </summary>
/// <param name="hhk">C++ ( hhk [in, optional]. Type: HHOOK )<br />This parameter is ignored. </param>
/// <param name="nCode">
///     C++ ( nCode [in]. Type: int )<br />The hook code passed to the current hook procedure. The next
///     hook procedure uses this code to determine how to process the hook information.
/// </param>
/// <param name="wParam">
///     C++ ( wParam [in]. Type: WPARAM )<br />The wParam value passed to the current hook procedure. The
///     meaning of this parameter depends on the type of hook associated with the current hook chain.
/// </param>
/// <param name="lParam">
///     C++ ( lParam [in]. Type: LPARAM )<br />The lParam value passed to the current hook procedure. The
///     meaning of this parameter depends on the type of hook associated with the current hook chain.
/// </param>
/// <returns>
///     C++ ( Type: LRESULT )<br />This value is returned by the next hook procedure in the chain. The current hook
///     procedure must also return this value. The meaning of the return value depends on the hook type. For more
///     information, see the descriptions of the individual hook procedures.
/// </returns>
/// <remarks>
///     <para>
///     Hook procedures are installed in chains for particular hook types. <see cref="CallNextHookEx" /> calls the
///     next hook in the chain.
///     </para>
///     <para>
///     Calling CallNextHookEx is optional, but it is highly recommended; otherwise, other applications that have
///     installed hooks will not receive hook notifications and may behave incorrectly as a result. You should call
///     <see cref="CallNextHookEx" /> unless you absolutely need to prevent the notification from being seen by other
///     applications.
///     </para>
/// </remarks>
[DllImport("user32.dll")]
static extern IntPtr CallNextHookEx(IntPtr hhk, int nCode, IntPtr wParam,
   IntPtr lParam);

// overload for use with LowLevelKeyboardProc
[DllImport("user32.dll")]
static extern IntPtr CallNextHookEx(IntPtr hhk, int nCode, WM wParam, [In]KBDLLHOOKSTRUCT lParam);

// overload for use with LowLevelMouseProc
[DllImport("user32.dll")]
static extern IntPtr CallNextHookEx(IntPtr hhk, int nCode, WM wParam, [In]MSLLHOOKSTRUCT lParam);

VB.NET Signature:

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

' overload for use with LowLevelKeyboardProc
<DllImport("user32.dll")> _
Private Shared Function CallNextHookEx(ByVal hhk As IntPtr, ByVal nCode As Integer, ByVal wParam As WindowsMessages, <[In]()> ByRef lParam As KBDLLHOOKSTRUCT) As IntPtr
End Function

' overload for use with LowLevelMouseProc
<DllImport("user32.dll")> _
Private Shared Function CallNextHookEx(ByVal hhk As IntPtr, ByVal nCode As Integer, ByVal wParam As WindowsMessages, <[In]()> ByRef lParam As MSLLHOOKSTRUCT) As IntPtr
End Function

VB Signature

Public Declare Function CallNextHookEx Lib "user32" _
          (ByVal hHook As Long, _
           ByVal ncode As Long, _
           ByVal wParam As WindowsMessages, _
           lParam As Any) As Long

' overload for use with LowLevelKeyboardProc
Public Declare Function CallNextHookExKbd Lib "user32" Alias "CallNextHookEx" _
          (ByVal hHook As Long, _
           ByVal ncode As Long, _
           ByVal wParam As WindowsMessages, _
           lParam As KBDLLHOOKSTRUCT) As Long

' overload for use with LowLevelMouseProc
Public Declare Function CallNextHookExMse Lib "user32" Alias "CallNextHookEx" _
          (ByVal hHook As Long, _
           ByVal ncode As Long, _
           ByVal wParam As WindowsMessages, _
           lParam As MSLLHOOKSTRUCT) As Long

User-Defined Types:

WindowsMessages,KBDLLHOOKSTRUCT,MSLLHOOKSTRUCT

Notes:

hhk is ignored, so you can use IntPtr.Zero

Tips & Tricks:

Please add some!

Sample Code:

Please add some!

Alternative Managed API:

The ManagedWindowsApi project (http://mwinapi.sourceforge.net) provides a Hook class and subclasses for Journal hooks, Message hooks and Low-Level hooks.

Please edit this page!

Do you have...

• helpful tips or sample code to share for using this API in managed code?
• corrections to the existing content?
• variations of the signature you want to share?
• additional languages you want to include?

Select "Edit This Page" on the right hand toolbar and edit it! Or add new pages containing supporting types needed for this API (structures, delegates, and more).