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  [DllImport("kernel32.dll",EntryPoint="GetSystemPowerStatus")]   //win32 api

        private static extern void GetSystemPowerStatus(ref SYSTEM_POWER_STATUS lpSystemPowerStatus);   

         public struct SYSTEM_POWER_STATUS    //结构体

         {

             public Byte ACLineStatus;                //0 = offline, 1 = Online, 255 = UnKnown Status.

             public Byte BatteryFlag;

            public Byte BatteryLifePercent;

            public Byte Reserved1;

            public int BatteryLifeTime;

             public int BatteryFullLifeTime;

         }  

        /// <summary>

        ///  获取系统电量百分比

        /// </summary>

        /// <returns></returns>

        public static float GetSystemPower()

        {

            SYSTEM_POWER_STATUS SysPower = new SYSTEM_POWER_STATUS();

            GetSystemPowerStatus(ref SysPower);

            return SysPower.BatteryLifePercent;

        }