How to shutdown Window by C#?????

Add a reference to System.Management and import the namespace System.Management then do something like the following. void ShutdownLocalMachine() { ManagementObjectSearcher searcher = new ManagementObjectSearcher("SELECT * FROM Win32_OperatingSystem WHERE Primary = TRUE"); foreach (ManagementObject os in searcher.Get()) { bool prev = os.Scope.Options.EnablePrivileges; os.Scope.Options.EnablePrivileges = true; ManagementBaseObject inParams = os.GetMethodParameters("Shutdown"); ManagementBaseObject outParams = os.InvokeMethod("Shutdown", inParams, null); os.Scope.Options.EnablePrivileges = prev; } }