Implement alt to toggle to previous window(s)

2025-08-26 20:42:50 +02:00
parent 48d3af7c94
commit 5e95937ae9
3 changed files with 90 additions and 24 deletions
--- a/DD2Switcher/KeyboardHook.cs
+++ b/DD2Switcher/KeyboardHook.cs
@@ -0,0 +1,64 @@
+using System;
+using System.Diagnostics;
+using System.Windows.Forms;
+using System.Runtime.InteropServices;
+
+class KeyboardHook {
+    private const int WH_KEYBOARD_LL = 13;
+    private const int WM_KEYDOWN = 0x0104;
+    private const int WM_KEYUP = 0x0101;
+    private static LowLevelKeyboardProc _proc = HookCallback;
+    private static IntPtr _hookID = IntPtr.Zero;
+
+    public static int previousEvent = 0;
+    public static event EventHandler<int> KeyDown;
+    public static event EventHandler<int> KeyUp;
+
+    public static void Start() {
+        _hookID = SetHook(_proc);
+    }
+
+    public static void Stop() {
+        UnhookWindowsHookEx(_hookID);
+    }
+
+    private static IntPtr SetHook(LowLevelKeyboardProc proc) {
+        using (Process curProcess = Process.GetCurrentProcess()) using (ProcessModule curModule =
+                                                                            curProcess.MainModule) {
+            return SetWindowsHookEx(WH_KEYBOARD_LL, proc, GetModuleHandle(curModule.ModuleName), 0);
+        }
+    }
+
+    private delegate IntPtr LowLevelKeyboardProc(int nCode, IntPtr wParam, IntPtr lParam);
+
+    private static IntPtr HookCallback(int nCode, IntPtr wParam, IntPtr lParam) {
+        if (nCode >= 0) {
+            int vkCode = Marshal.ReadInt32(lParam);
+            int pero = (int)wParam * 1000 + vkCode;
+            if (pero != previousEvent) {
+                if (wParam == (IntPtr)WM_KEYDOWN) {
+                    KeyDown?.Invoke(null, vkCode);
+                } else if (wParam == (IntPtr)WM_KEYUP) {
+                    KeyUp?.Invoke(null, vkCode);
+                }
+                previousEvent = pero;
+            } else {
+                Console.WriteLine("Same event");
+            }
+        }
+        return CallNextHookEx(_hookID, nCode, wParam, lParam);
+    }
+
+    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
+    private static extern IntPtr SetWindowsHookEx(int idHook, LowLevelKeyboardProc lpfn, IntPtr hMod, uint dwThreadId);
+
+    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
+    [return:MarshalAs(UnmanagedType.Bool)]
+    private static extern bool UnhookWindowsHookEx(IntPtr hhk);
+
+    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
+    private static extern IntPtr CallNextHookEx(IntPtr hhk, int nCode, IntPtr wParam, IntPtr lParam);
+
+    [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
+    private static extern IntPtr GetModuleHandle(string lpModuleName);
+}