如何让UWP应用不获取焦点，保留外部文本光标？

核心思路 #

UWP没有HWND直接设置无激活属性的机制，但可以通过应用视图非激活模式结合模拟键盘输入实现需求，同时保留HandwritingView的手写识别功能。

具体实现步骤 #

1. 设置应用视图为非激活模式 #

在App.xaml.cs的OnLaunched方法中，将应用视图配置为启动和交互时不抢占焦点：

protected override void OnLaunched(LaunchActivatedEventArgs e)
{
    Frame rootFrame = Window.Current.Content as Frame;
    if (rootFrame == null)
    {
        rootFrame = new Frame();
        rootFrame.NavigationFailed += OnNavigationFailed;
        Window.Current.Content = rootFrame;
    }

    if (e.PrelaunchActivated == false)
    {
        if (rootFrame.Content == null)
        {
            rootFrame.Navigate(typeof(MainPage), e.Arguments);
        }
        Window.Current.Activate();
        
        // 关键：设置应用视图为非激活模式
        var currentView = CoreApplication.GetCurrentView();
        currentView.ActivationMode = CoreApplicationViewActivationMode.NonActivated;
        currentView.SetPreferredMinSize(new Size(1440, 1300));
    }
}

2. 调整控件焦点行为 #

禁用TextBox的焦点获取能力，避免交互时触发焦点抢占：

public MainPage()
{
    this.InitializeComponent();

    tbHandWriteView.IsHandwritingViewEnabled = true;
    tbHandWriteView.HandwritingView.InputDeviceTypes = Windows.UI.Core.CoreInputDeviceTypes.Touch | Windows.UI.Core.CoreInputDeviceTypes.Pen;
    tbHandWriteView.HandwritingView.PlacementAlignment = HandwritingPanelPlacementAlignment.TopLeft;
    tbHandWriteView.HandwritingView.Width = 1000;
    tbHandWriteView.HandwritingView.Height = 1000;
    tbHandWriteView.HandwritingView.Visibility = Visibility.Visible;

    // 禁用TextBox的焦点相关属性
    tbHandWriteView.IsTabStop = false;
    tbHandWriteView.FocusVisualPrimaryThickness = new Thickness(0);
    tbHandWriteView.FocusVisualSecondaryThickness = new Thickness(0);
    
    // 监听手写完成事件，将识别文本发送到外部光标
    tbHandWriteView.HandwritingView.TextSubmitted += HandwritingView_TextSubmitted;

    tbHandWriteView.HandwritingView.TryOpen();
}

3. 模拟键盘输入传递文本 #

手写完成后，通过Windows API模拟键盘输入，将识别文本直接发送到当前激活的外部窗口（需添加Windows Desktop Extensions for the UWP引用）：

private async void HandwritingView_TextSubmitted(HandwritingView sender, HandwritingPanelTextSubmittedEventArgs args)
{
    string recognizedText = args.SubmittedText;
    if (!string.IsNullOrEmpty(recognizedText))
    {
        // 短暂延迟确保外部窗口重新获得焦点
        await Task.Delay(100);
        // 逐字符模拟键盘输入
        foreach (char c in recognizedText)
        {
            SimulateKeyPress(c);
        }
        // 清空本地TextBox内容
        tbHandWriteView.Text = "";
    }
}

// 模拟键盘输入的辅助方法
private void SimulateKeyPress(char c)
{
    INPUT input = new INPUT();
    input.type = INPUT_KEYBOARD;
    input.ki.wVk = 0;
    input.ki.wScan = c;
    input.ki.dwFlags = KEYEVENTF_UNICODE;
    input.ki.time = 0;
    input.ki.dwExtraInfo = IntPtr.Zero;

    SendInput(1, ref input, Marshal.SizeOf(input));

    // 模拟按键释放
    input.ki.dwFlags = KEYEVENTF_UNICODE | KEYEVENTF_KEYUP;
    SendInput(1, ref input, Marshal.SizeOf(input));
}

// 导入Windows API
[DllImport("user32.dll", SetLastError = true)]
private static extern uint SendInput(uint nInputs, ref INPUT pInputs, int cbSize);

private struct INPUT
{
    public int type;
    public KEYBDINPUT ki;
}

private struct KEYBDINPUT
{
    public ushort wVk;
    public ushort wScan;
    public uint dwFlags;
    public uint time;
    public IntPtr dwExtraInfo;
}

private const int INPUT_KEYBOARD = 1;
private const uint KEYEVENTF_UNICODE = 0x0004;
private const uint KEYEVENTF_KEYUP = 0x0002;

4. 配置应用清单（可选） #

在Package.appxmanifest中添加桌面扩展支持，确保模拟输入功能正常：

<Package ...>
  <Applications>
    <Application ...>
      <Extensions>
        <uap:Extension Category="windows.desktop">
          <uap:Desktop>
            <uap:DesktopApplication Path="YourApp.exe" />
          </uap:Desktop>
        </uap:Extension>
      </Extensions>
    </Application>
  </Applications>
</Package>

关键说明 #

• CoreApplicationViewActivationMode.NonActivated是UWP实现无焦点窗口的核心，确保应用不会抢占外部窗口焦点；
• 模拟键盘输入是跨窗口传递文本的可靠方式，无需依赖窗口句柄交互；
• 非激活模式下应用部分系统交互功能会受限，需根据实际需求调整。

内容的提问来源于stack exchange，提问作者Kai-Han Lo