wpf、winform获取屏幕缩放百分比

一、WPF

第一部分

 public class ScreenHelper
        {
            /// <summary>
            /// 获取缩放比例
            /// </summary>
            /// <returns></returns>
            public static double GetScalingRatio()
            {
                var logicalHeight = GetLogicalHeight();
                var actualHeight = GetActualHeight();

                if (logicalHeight > 0 && actualHeight > 0)
                {
                    return logicalHeight / actualHeight;
                }

                return 1;
            }

            private static double GetActualHeight()
            {
                return SystemParameters.PrimaryScreenHeight;
            }

            private static double GetLogicalHeight()
            {
                var logicalHeight = 0.0;

                WindowsMonitorAPI.MonitorEnumProc proc = (m, h, lm, lp) =>
                {
                    WindowsMonitorAPI.MONITORINFOEX info = new WindowsMonitorAPI.MONITORINFOEX();
                    WindowsMonitorAPI.GetMonitorInfo(new HandleRef(null, m), info);

                    //是否为主屏
                    if ((info.dwFlags & 0x00000001) != 0)
                    {
                        logicalHeight = info.rcMonitor.bottom - info.rcMonitor.top;
                    }

                    return true;
                };
                WindowsMonitorAPI.EnumDisplayMonitors(WindowsMonitorAPI.NullHandleRef, null, proc, IntPtr.Zero);

                return logicalHeight;
            }
        }

第二部分

 public static class WindowsMonitorAPI
        {
            private const string User32 = "user32.dll";

            [DllImport(User32, CharSet = CharSet.Auto)]
            [ResourceExposure(ResourceScope.None)]
            public static extern bool GetMonitorInfo(HandleRef hmonitor, [In, Out] MONITORINFOEX info);

            [DllImport(User32, ExactSpelling = true)]
            [ResourceExposure(ResourceScope.None)]
            public static extern bool EnumDisplayMonitors(HandleRef hdc, COMRECT rcClip, MonitorEnumProc lpfnEnum, IntPtr dwData);

            public delegate bool MonitorEnumProc(IntPtr monitor, IntPtr hdc, IntPtr lprcMonitor, IntPtr lParam);

            [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto, Pack = 4)]
            public class MONITORINFOEX
            {
                internal int cbSize = Marshal.SizeOf(typeof(MONITORINFOEX));
                internal RECT rcMonitor = new RECT();
                internal RECT rcWork = new RECT();
                internal int dwFlags = 0;
                [MarshalAs(UnmanagedType.ByValArray, SizeConst = 32)]
                internal char[] szDevice = new char[32];
            }

            [StructLayout(LayoutKind.Sequential)]
            public struct RECT
            {
                public int left;
                public int top;
                public int right;
                public int bottom;

                public RECT(Rect r)
                {
                    left = (int)r.Left;
                    top = (int)r.Top;
                    right = (int)r.Right;
                    bottom = (int)r.Bottom;
                }
            }

            [StructLayout(LayoutKind.Sequential)]
            public class COMRECT
            {
                public int left;
                public int top;
                public int right;
                public int bottom;
            }

            public static readonly HandleRef NullHandleRef = new HandleRef(null, IntPtr.Zero);
        }

调用

dynamic bl = ScreenHelper.GetScalingRatio();

二、Winform

 [DllImport("gdi32.dll", EntryPoint = "GetDeviceCaps", SetLastError = true)]
        public static extern int GetDeviceCaps(IntPtr hdc, int nIndex);

        enum DeviceCap
        {
            VERTRES = 10,
            PHYSICALWIDTH = 110,
            SCALINGFACTORX = 114,
            DESKTOPVERTRES = 117,
        }

        private static double GetScreenScalingFactor()
        {
            var g = Graphics.FromHwnd(IntPtr.Zero);
            IntPtr desktop = g.GetHdc();
            var physicalScreenHeight = GetDeviceCaps(desktop, (int)DeviceCap.DESKTOPVERTRES);

            var screenScalingFactor =
                (double)physicalScreenHeight / Screen.PrimaryScreen.Bounds.Height;
            //SystemParameters.PrimaryScreenHeight;

            return screenScalingFactor;
        }

调用

dynamic bl = GetScreenScalingFactor();