Want to call .net func _Help::ShowHelpIndex.Here is the link in msdn:https://msdn.microsoft.com/en-us//library/system.windows.forms.help.showhelpindex. I wrote the script below: $dll = DllOpen("C:\Program Files\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.0\System.Windows.Forms.dll") $result = DllCall($dll, "none", "ShowHelpIndex","HWND", 0,"wstr","D:\Program Files\AutoIt3\AutoIt3CHS.chm") _check_result() DllClose($dll) Func _check_result() If @error Then ConsoleWrite(">--|error:=" & @error & "|--<") ConsoleWrite(@LF) Else ConsoleWrite(">--|$result:=" & $result[0] & "|--<") ConsoleWrite(@LF) EndIf EndFunc Can someone give some advices? tks in advance