c# - 正确检测键盘布局

Question

我有一个 winforms 应用程序，我需要在其中获取用户的当前键盘布局。为此，我使用了 System.Windows.Forms.InputLanguage.CurrentInputLanguage.LayoutName。

只要用户将表单作为事件窗口，这就可以正常工作，一旦他关注其他内容并更改语言，前一个属性将不会返回正确的值，它将返回上次使用的语言，而表单仍然是事件窗口。

有没有一种方法我可以获得用户键盘布局的名称，即使他没有关注表单，对可以使用的内容没有限制。

Answer 1

正如您可能已经知道的那样，System.Windows.Forms.InputLanguage.CurrentInputLanguage.LayoutName 属性返回当前线程的键盘布局，无论您选择什么布局，执行线程都将保持不变，除非您选择窗口并更改该窗口的键盘输入布局。

也就是说，您实际上是想检查当前的键盘布局文化，并能够知道它何时发生变化。前一段时间我有类似的要求，我想出了以下代码，它对我很有帮助:

public delegate void KeyboardLayoutChanged(int oldCultureInfo, int newCultureInfo);

class KeyboardLayoutWatcher : IDisposable
{
    private readonly Timer _timer;
    private int _currentLayout = 1033;


    public KeyboardLayoutChanged KeyboardLayoutChanged;

    public KeyboardLayoutWatcher()
    {
        _timer = new Timer(new TimerCallback(CheckKeyboardLayout), null, TimeSpan.FromSeconds(1), TimeSpan.FromSeconds(1));
    }

    [DllImport("user32.dll")] static extern IntPtr GetForegroundWindow();
    [DllImport("user32.dll")] static extern uint GetWindowThreadProcessId(IntPtr hwnd, IntPtr proccess);
    [DllImport("user32.dll")] static extern IntPtr GetKeyboardLayout(uint thread);
    public int GetCurrentKeyboardLayout()
    {
        try
        {
            IntPtr foregroundWindow = GetForegroundWindow();
            uint foregroundProcess = GetWindowThreadProcessId(foregroundWindow, IntPtr.Zero);
            int keyboardLayout = GetKeyboardLayout(foregroundProcess).ToInt32() & 0xFFFF;

            if (keyboardLayout == 0)
            {
                // something has gone wrong - just assume English
                keyboardLayout = 1033;
            }
            return keyboardLayout;
        }
        catch (Exception ex)
        {
            // if something goes wrong - just assume English
            return 1033;
        }
    }

    private void CheckKeyboardLayout(object sender)
    {
        var layout = GetCurrentKeyboardLayout();
        if (_currentLayout != layout && KeyboardLayoutChanged != null)
        {
            KeyboardLayoutChanged(_currentLayout, layout);
            _currentLayout = layout;
        }

    }

    private void ReleaseUnmanagedResources()
    {
        _timer.Dispose();
    }

    public void Dispose()
    {
        ReleaseUnmanagedResources();
        GC.SuppressFinalize(this);
    }

    ~KeyboardLayoutWatcher()
    {
        ReleaseUnmanagedResources();
    }
}

像这样使用它:

        new KeyboardLayoutWatcher().KeyboardLayoutChanged += (o, n) =>
        {
            this.CurrentLayoutLabel.Text = $"{o} -> {n}"; // old and new KB layout
        };