WPF自动弹出软件键盘

使用全局类型获取焦点事件

    EventManager.RegisterClassHandler(typeof(TextBox), TextBox.GotFocusEvent, new RoutedEventHandler(TextBox_GotFocus));
    EventManager.RegisterClassHandler(typeof(TextBox), TextBox.LostFocusEvent, new RoutedEventHandler(TextBox_LostFocus));
    private void TextBox_GotFocus(object sender, RoutedEventArgs e)
     {
      //获取焦点打开键盘
     }

   private void TextBox_LostFocus(object sender, RoutedEventArgs e)
   {
    //失去焦点关闭键盘
   }

NuGet包：Microsoft.Xaml.Behaviors.Wpf

using Microsoft.Xaml.Behaviors;
using System.Diagnostics;
using System.Windows.Controls;

public class ShowTouchKeyboardBehavior : Behavior<TextBox>
{
    protected override void OnAttached()
    {
        base.OnAttached();
        AssociatedObject.GotFocus += AssociatedObject_GotFocus;
        AssociatedObject.PreviewMouseDown += AssociatedObject_PreviewMouseDown;
    }

    protected override void OnDetaching()
    {
        base.OnDetaching();
        AssociatedObject.GotFocus -= AssociatedObject_GotFocus;
        AssociatedObject.PreviewMouseDown -= AssociatedObject_PreviewMouseDown;
    }

    private void AssociatedObject_PreviewMouseDown(object sender, System.Windows.Input.MouseButtonEventArgs e)
    {
        ShowTouchKeyboard();
    }

    private void AssociatedObject_GotFocus(object sender, RoutedEventArgs e)
    {
        ShowTouchKeyboard();
    }

    private void ShowTouchKeyboard()
    {
        try
        {
            Process.Start(new ProcessStartInfo
            {
                FileName = "cmd.exe",
                Arguments = "/c start tabtip:",
                WindowStyle = ProcessWindowStyle.Hidden,
                CreateNoWindow = true
            });
        }
        catch
        {
            // 备用方案
            try
            {
                Process.Start("osk.exe");
            }
            catch { }
        }
    }
}

在XAML中使用：

<Window x:Class="YourNamespace.MainWindow"
       xmlns:behaviors="clr-namespace:RemoteControl" xmlns:i="http://schemas.microsoft.com/xaml/behaviors"
    <Grid>
        <TextBox Width="200" Height="30">
            <i:Interaction.Behaviors>
                <behaviors:ShowTouchKeyboardBehavior/>
            </i:Interaction.Behaviors>
        </TextBox>
        
        <PasswordBox Width="200" Height="30" Margin="0,40,0,0">
            <i:Interaction.Behaviors>
                <behaviors:ShowTouchKeyboardBehavior/>
            </i:Interaction.Behaviors>
        </PasswordBox>
    </Grid>
</Window>

或者另外一种xaml附加法

public static class TouchKeyboardHelper
{
    public static readonly DependencyProperty EnableTouchKeyboardProperty =
        DependencyProperty.RegisterAttached(
            "EnableTouchKeyboard", typeof(bool), typeof(TouchKeyboardHelper),
            new PropertyMetadata(false, OnEnableTouchKeyboardChanged));

    public static void SetEnableTouchKeyboard(UIElement element, bool value)
        => element.SetValue(EnableTouchKeyboardProperty, value);

    public static bool GetEnableTouchKeyboard(UIElement element)
        => (bool)element.GetValue(EnableTouchKeyboardProperty);

    private static void OnEnableTouchKeyboardChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        if (d is Control control)
        {
            if ((bool)e.NewValue)
                control.GotFocus += Control_GotFocus;
            else
                control.GotFocus -= Control_GotFocus;
        }
    }

    private static void Control_GotFocus(object sender, RoutedEventArgs e)
    {
        string tabTipPath = @"C:\Program Files\Common Files\Microsoft Shared\ink\TabTip.exe";
        if (File.Exists(tabTipPath) && Process.GetProcessesByName("TabTip").Length == 0)
            Process.Start(tabTipPath);
    }
}

XAML里如下使用

<TextBox Width="200"
         Height="40"
         local:TouchKeyboardHelper.EnableTouchKeyboard="True" />