protected void Install()
{
// make sure not already installed
if (_HookHandle != IntPtr.Zero)
{
return;
}
var mod = ModuleHelper.GetCurrentModule();
// install system-wide hook
_HookHandle = HookAPI.SetWindowsHookEx(
_HookType,
_HookFunction,
mod.BaseAddress,
0);
if (_HookHandle == IntPtr.Zero)
{
try
{
EventLog.WriteEntry(
"HookApp",
string.Format("Failed to set hook. Error {0}.", Marshal.GetLastWin32Error()),
EventLogEntryType.Warning);
}
catch
{; }
}
}
protected void Uninstall()
{
if (_HookHandle != IntPtr.Zero)
{
// uninstall system-wide hook
HookAPI.UnhookWindowsHookEx(_HookHandle);
_HookHandle = IntPtr.Zero;
}
}
// hook function called by system
protected int HookCallback(int code, IntPtr wParam, IntPtr lParam)
{
if (code < 0)
{
return(HookAPI.CallNextHookEx(_HookHandle, code, wParam, lParam));
}
HookParam structData = (HookParam)Marshal.PtrToStructure(lParam, typeof(HookParam));
if (ProcessHook(wParam, structData))
{
return(HookAPI.CallNextHookEx(_HookHandle, code, wParam, lParam));
}
return(-1);
}