Initial commit: RemSound v1.0

src/RemSound.App/AccessibleCheckBox.cs

@@ -0,0 +1,65 @@
+using System.Runtime.InteropServices;
+
+namespace RemSound.App;
+
+/// <summary>
+/// Direct NotifyWinEvent shim. WinForms focus changes nominally fire MSAA EVENT_OBJECT_FOCUS,
+/// but in some scenarios (focus moving from a key handler that runs synchronously in
+/// ProcessCmdKey, focus into a control inside a wrapper container, etc.) NVDA's screen-reader
+/// listener doesn't pick up the announcement. Re-firing the event explicitly forces it.
+///
+/// Same pattern documented in claude-notes.md for the AccessibleCheckBox state-change fix —
+/// "the load-bearing piece is the FOCUS re-fire."
+/// </summary>
+internal static class WinEventNotifier
+{
+    private const uint EVENT_OBJECT_FOCUS = 0x8005;
+    private const int OBJID_CLIENT = unchecked((int)0xFFFFFFFC);
+    private const int CHILDID_SELF = 0;
+
+    [DllImport("user32.dll")]
+    private static extern void NotifyWinEvent(uint eventMin, nint hwnd, int idObject, int idChild);
+
+    public static void NotifyFocus(Control control)
+    {
+        if (control.IsHandleCreated)
+        {
+            NotifyWinEvent(EVENT_OBJECT_FOCUS, control.Handle, OBJID_CLIENT, CHILDID_SELF);
+        }
+    }
+}
+
+/// <summary>
+/// CheckBox variant that fires the right MSAA WinEvents on every state change so NVDA
+/// reliably announces "checked" / "not checked" — including for spacebar toggles while the
+/// checkbox already has focus, which is the failure mode plain WinForms CheckBox has on
+/// .NET 10. The recipe (proven in the loxone desktop app):
+///   1. Fire EVENT_OBJECT_STATECHANGE so any listener knows the toggle state changed.
+///   2. If the checkbox is currently focused, ALSO re-fire EVENT_OBJECT_FOCUS — this is what
+///      forces NVDA to re-announce the focused control, bringing the new state with it.
+/// We call <c>user32.NotifyWinEvent</c> directly because the managed
+/// <see cref="Control.AccessibilityNotifyClients"/> path only fires the state event without
+/// the focus re-fire, which leaves NVDA silent.
+/// </summary>
+internal sealed class AccessibleCheckBox : CheckBox
+{
+    private const uint EVENT_OBJECT_FOCUS = 0x8005;
+    private const uint EVENT_OBJECT_STATECHANGE = 0x800A;
+    private const int OBJID_CLIENT = unchecked((int)0xFFFFFFFC);
+    private const int CHILDID_SELF = 0;
+
+    [DllImport("user32.dll")]
+    private static extern void NotifyWinEvent(uint eventMin, nint hwnd, int idObject, int idChild);
+
+    protected override void OnCheckedChanged(EventArgs e)
+    {
+        base.OnCheckedChanged(e);
+        if (!IsHandleCreated) return;
+
+        NotifyWinEvent(EVENT_OBJECT_STATECHANGE, Handle, OBJID_CLIENT, CHILDID_SELF);
+        if (Focused)
+        {
+            NotifyWinEvent(EVENT_OBJECT_FOCUS, Handle, OBJID_CLIENT, CHILDID_SELF);
+        }
+    }
+}