Brightness hotkeys fix

app/Display/ScreenBrightness.cs

@@ -0,0 +1,47 @@
+namespace GHelper.Display
+{
+    using System;
+    using System.Diagnostics;
+    using System.Management;
+
+    public static class ScreenBrightness
+    {
+        public static int Get()
+        {
+            using var mclass = new ManagementClass("WmiMonitorBrightness")
+            {
+                Scope = new ManagementScope(@"\\.\root\wmi")
+            };
+            using var instances = mclass.GetInstances();
+            foreach (ManagementObject instance in instances)
+            {
+                return (byte)instance.GetPropertyValue("CurrentBrightness");
+            }
+            return 0;
+        }
+
+        public static void Set(int brightness)
+        {
+            using var mclass = new ManagementClass("WmiMonitorBrightnessMethods")
+            {
+                Scope = new ManagementScope(@"\\.\root\wmi")
+            };
+            using var instances = mclass.GetInstances();
+            var args = new object[] { 1, brightness };
+            foreach (ManagementObject instance in instances)
+            {
+                instance.InvokeMethod("WmiSetBrightness", args);
+            }
+        }
+
+        public static int Adjust(int delta)
+        {
+            int brightness = Get();
+            Debug.WriteLine(brightness);
+            brightness = Math.Min(100, Math.Max(0, brightness + delta));
+            Set(brightness);
+            return brightness;
+        }
+
+    }
+}