C# winform 获取屏幕分辨率缩放率，获取屏幕设置分辨率

解决问题：1）当需要抓取显示器分辨率的缩放比例时。2）当屏幕显示缩放设置不等于100%，导致分辨率改变，Screen.PrimaryScreen.Bounds抓取不到实际设置的分辨率时。

解决方案：使用GetDeviceCaps函数。

/// <summary>
        /// 设备数据函数
        /// </summary>
        /// <param name="hdc"></param>
        /// <param name="nIndex"></param>
        /// <returns></returns>
        [DllImport("gdi32.dll", EntryPoint = "GetDeviceCaps", SetLastError = true)]
        public static extern int GetDeviceCaps(IntPtr hdc, int nIndex);

        private static double GetScreenScalingFactor()
        {
            var g = Graphics.FromHwnd(IntPtr.Zero);
            IntPtr desktop = g.GetHdc();
            var physicalScreenHeight = GetDeviceCaps(desktop, 117);//硬件显示器分辨率实际设置的高
            var physicalScreenWidth = GetDeviceCaps(desktop, 118);//硬件显示器分辨率实际设置的宽
            var screenScalingFactor = (double)physicalScreenHeight / Screen.PrimaryScreen.Bounds.Height;//将实际的高除以抓取的换算过的高就等于缩放率，同理当需要获取实际宽高时，直接获取函数结果即可
            return screenScalingFactor;
        }