WPF开发经验-实现自带触控键盘的TextBox

一 引入

项目有个新需求，当点击或触碰TextBox时，基于TextBox的相对位置，弹出一个自定义的Keyboard，如下图所示：

二 KeyboardControl

先实现一个自定义的KeyboardControl，它继承自Window。

Xaml代码如下：

<Window x:Class="WpfApp1.KeyboardControl"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:local="clr-namespace:WpfApp1" AllowsTransparency="True" WindowStyle="None"
        ResizeMode="NoResize" Background="Transparent" Height="290" Width="668">
    <FrameworkElement.Resources>
        <ResourceDictionary>
            <Style TargetType="{x:Type Button}" x:Key="btnNum">
                <Setter Property="Width" Value="50"/>
                <Setter Property="Height" Value="50"/>
                <Setter Property="Margin" Value="0 0 5 5"/>
                <Setter Property="HorizontalContentAlignment" Value="Center" />
                <Setter Property="VerticalContentAlignment" Value="Center" />
                <Setter Property="Cursor" Value="Hand"/>
                <Setter Property="Template">
                    <Setter.Value>
                        <ControlTemplate TargetType="{x:Type Button}">
                            <Border Name="border" BorderBrush="#FF474747" BorderThickness="1" CornerRadius="6">
                                <Border.Background>
                                    <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
                                        <GradientStop Color="#FFCCCCCC" />
                                        <GradientStop Color="WhiteSmoke" Offset="0.5" />
                                        <GradientStop Color="#FFCCCCCC" Offset="1" />
                                    </LinearGradientBrush>
                                </Border.Background>
                                <ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center"
                                    TextElement.Foreground="#333333" TextElement.FontSize="18" />
                            </Border>
                        </ControlTemplate>
                    </Setter.Value>
                </Setter>
            </Style>
            <Style TargetType="{x:Type Button}" x:Key="btnFunc">
                <Setter Property="HorizontalContentAlignment" Value="Center" />
                <Setter Property="VerticalContentAlignment" Value="Center" />
                <Setter Property="Width" Value="50"/>
                <Setter Property="Height" Value="50"/>
                <Setter Property="Margin" Value="0 0 5 5"/>
                <Setter Property="Foreground" Value="#333333"/>
                <Setter Property="Cursor" Value="Hand"/>
                <Setter Property="Template">
                    <Setter.Value>
                        <ControlTemplate TargetType="{x:Type Button}">
                            <Border
                                Name="border"
                                BorderBrush="#FF565656"
                                BorderThickness="1"
                                CornerRadius="6"  Background="Orange">
                                <ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center"
                                    TextElement.Foreground="White" TextElement.FontSize="18" />
                            </Border>
                        </ControlTemplate>
                    </Setter.Value>
                </Setter>
            </Style>
            <local:CapsConverter x:Key="CapsConverter"/>
        </ResourceDictionary>
    </FrameworkElement.Resources>

    <Border Background="Gray" CornerRadius="6" BorderThickness="1" BorderBrush="#333333">
        <StackPanel Margin="5 10 5 5" >
            <Grid>
                <TextBox Name="tbValue" FontSize="28" Height="40"
                    Background="Transparent" BorderBrush="Silver" BorderThickness="1"
                    Foreground="White" HorizontalContentAlignment="Right"
                    SelectionChanged="tbValue_TextChanged"
                    TextChanged="tbValue_TextChanged" />
            </Grid>
            <WrapPanel  Orientation="Vertical" >
                <WrapPanel Margin="0 10 0 0">
                    <Button Content="1" Click="Button_Click"  Style="{StaticResource btnNum}" />
                    <Button Content="2" Click="Button_Click"  Style="{StaticResource btnNum}" />
                    <Button Content="3" Click="Button_Click"  Style="{StaticResource btnNum}" />

                    <Button Content="4" Click="Button_Click"  Style="{StaticResource btnNum}" />
                    <Button Content="5" Click="Button_Click"  Style="{StaticResource btnNum}" />
                    <Button Content="6" Click="Button_Click"  Style="{StaticResource btnNum}" />

                    <Button Content="7" Click="Button_Click"  Style="{StaticResource btnNum}" />
                    <Button Content="8" Click="Button_Click"  Style="{StaticResource btnNum}" />
                    <Button Content="9" Click="Button_Click"  Style="{StaticResource btnNum}" />

                    <Button Content="0" Click="Button_Click"  Style="{StaticResource btnNum}" />
                    <Button Content="-" Click="Button_Click"  Style="{StaticResource btnNum}" />
                    <Button Content="Del" Click="DELButton_Click"   Style="{StaticResource btnFunc}"  Margin="0 0 0 5"/>
                </WrapPanel>
                <WrapPanel Margin="25 0 0 0">
                    <Button Style="{StaticResource btnNum}" Content="{Binding Path=Caps,RelativeSource={RelativeSource AncestorType={x:Type local:KeyboardControl}},Converter={StaticResource CapsConverter},ConverterParameter=q}"
                            Click="Button_Click"/>
                    <Button Style="{StaticResource btnNum}" Content="{Binding Path=Caps,RelativeSource={RelativeSource AncestorType={x:Type local:KeyboardControl}},Converter={StaticResource CapsConverter},ConverterParameter=w}"
                            Click="Button_Click"/>
                    <Button Style="{StaticResource btnNum}" Content="{Binding Path=Caps,RelativeSource={RelativeSource AncestorType={x:Type local:KeyboardControl}},Converter={StaticResource CapsConverter},ConverterParameter=e}"
                            Click="Button_Click"/>
                    <Button Style="{StaticResource btnNum}" Content="{Binding Path=Caps,RelativeSource={RelativeSource AncestorType={x:Type local:KeyboardControl}},Converter={StaticResource CapsConverter},ConverterParameter=r}"
                             Click="Button_Click"/>
                    <Button Style="{StaticResource btnNum}" Content="{Binding Path=Caps,RelativeSource={RelativeSource AncestorType={x:Type local:KeyboardControl}},Converter={StaticResource CapsConverter},ConverterParameter=t}"
                             Click="Button_Click"/>
                    <Button Style="{StaticResource btnNum}" Content="{Binding Path=Caps,RelativeSource={RelativeSource AncestorType={x:Type local:KeyboardControl}},Converter={StaticResource CapsConverter},ConverterParameter=y}"
                             Click="Button_Click"/>
                    <Button Style="{StaticResource btnNum}" Content="{Binding Path=Caps,RelativeSource={RelativeSource AncestorType={x:Type local:KeyboardControl}},Converter={StaticResource CapsConverter},ConverterParameter=u}"
                             Click="Button_Click"/>
                    <Button Style="{StaticResource btnNum}" Content="{Binding Path=Caps,RelativeSource={RelativeSource AncestorType={x:Type local:KeyboardControl}},Converter={StaticResource CapsConverter},ConverterParameter=i}"
                             Click="Button_Click"/>
                    <Button Style="{StaticResource btnNum}" Content="{Binding Path=Caps,RelativeSource={RelativeSource AncestorType={x:Type local:KeyboardControl}},Converter={StaticResource CapsConverter},ConverterParameter=o}"
                             Click="Button_Click"/>
                    <Button Style="{StaticResource btnNum}" Content="{Binding Path=Caps,RelativeSource={RelativeSource AncestorType={x:Type local:KeyboardControl}},Converter={StaticResource CapsConverter},ConverterParameter=p}"
                             Click="Button_Click"/>
                    <Button Content="Clear" Click="ClearButton_Click"  Style="{StaticResource btnFunc}"  />
                </WrapPanel>
                <WrapPanel Margin="45 0 0 0">
                    <Button Style="{StaticResource btnNum}" Content="{Binding Path=Caps,RelativeSource={RelativeSource AncestorType={x:Type local:KeyboardControl}},Converter={StaticResource CapsConverter},ConverterParameter=a}"
                             Click="Button_Click"/>
                    <Button Style="{StaticResource btnNum}" Content="{Binding Path=Caps,RelativeSource={RelativeSource AncestorType={x:Type local:KeyboardControl}},Converter={StaticResource CapsConverter},ConverterParameter=s}"
                             Click="Button_Click"/>
                    <Button Style="{StaticResource btnNum}" Content="{Binding Path=Caps,RelativeSource={RelativeSource AncestorType={x:Type local:KeyboardControl}},Converter={StaticResource CapsConverter},ConverterParameter=d}"
                             Click="Button_Click"/>
                    <Button Style="{StaticResource btnNum}" Content="{Binding Path=Caps,RelativeSource={RelativeSource AncestorType={x:Type local:KeyboardControl}},Converter={StaticResource CapsConverter},ConverterParameter=f}"
                             Click="Button_Click"/>
                    <Button Style="{StaticResource btnNum}" Content="{Binding Path=Caps,RelativeSource={RelativeSource AncestorType={x:Type local:KeyboardControl}},Converter={StaticResource CapsConverter},ConverterParameter=g}"
                             Click="Button_Click"/>
                    <Button Style="{StaticResource btnNum}" Content="{Binding Path=Caps,RelativeSource={RelativeSource AncestorType={x:Type local:KeyboardControl}},Converter={StaticResource CapsConverter},ConverterParameter=h}"
                             Click="Button_Click"/>
                    <Button Style="{StaticResource btnNum}" Content="{Binding Path=Caps,RelativeSource={RelativeSource AncestorType={x:Type local:KeyboardControl}},Converter={StaticResource CapsConverter},ConverterParameter=j}"
                             Click="Button_Click"/>
                    <Button Style="{StaticResource btnNum}" Content="{Binding Path=Caps,RelativeSource={RelativeSource AncestorType={x:Type local:KeyboardControl}},Converter={StaticResource CapsConverter},ConverterParameter=k}"
                             Click="Button_Click"/>
                    <Button Style="{StaticResource btnNum}" Content="{Binding Path=Caps,RelativeSource={RelativeSource AncestorType={x:Type local:KeyboardControl}},Converter={StaticResource CapsConverter},ConverterParameter=l}"
                             Click="Button_Click"/>
                    <Button Content="." Click="Button_Click"  Style="{StaticResource btnNum}" />
                </WrapPanel>
                <WrapPanel Margin="70 0 0 0">
                    <Button Content="A/a" Click="CapsButton_Click"  Style="{StaticResource btnFunc}"  />
                    <Button Style="{StaticResource btnNum}" Content="{Binding Path=Caps,RelativeSource={RelativeSource AncestorType={x:Type local:KeyboardControl}},Converter={StaticResource CapsConverter},ConverterParameter=z}"
                             Click="Button_Click"/>
                    <Button Style="{StaticResource btnNum}" Content="{Binding Path=Caps,RelativeSource={RelativeSource AncestorType={x:Type local:KeyboardControl}},Converter={StaticResource CapsConverter},ConverterParameter=x}"
                             Click="Button_Click"/>
                    <Button Style="{StaticResource btnNum}" Content="{Binding Path=Caps,RelativeSource={RelativeSource AncestorType={x:Type local:KeyboardControl}},Converter={StaticResource CapsConverter},ConverterParameter=c}"
                             Click="Button_Click"/>
                    <Button Style="{StaticResource btnNum}" Content="{Binding Path=Caps,RelativeSource={RelativeSource AncestorType={x:Type local:KeyboardControl}},Converter={StaticResource CapsConverter},ConverterParameter=v}"
                             Click="Button_Click"/>
                    <Button Style="{StaticResource btnNum}" Content="{Binding Path=Caps,RelativeSource={RelativeSource AncestorType={x:Type local:KeyboardControl}},Converter={StaticResource CapsConverter},ConverterParameter=b}"
                             Click="Button_Click"/>
                    <Button Style="{StaticResource btnNum}" Content="{Binding Path=Caps,RelativeSource={RelativeSource AncestorType={x:Type local:KeyboardControl}},Converter={StaticResource CapsConverter},ConverterParameter=n}"
                             Click="Button_Click"/>
                    <Button Style="{StaticResource btnNum}" Content="{Binding Path=Caps,RelativeSource={RelativeSource AncestorType={x:Type local:KeyboardControl}},Converter={StaticResource CapsConverter},ConverterParameter=m}"
                             Click="Button_Click"/>
                    <Button Content="Cancel" Click="CancelButton_Click" IsCancel="True" Style="{StaticResource btnFunc}" Width="70"  />
                    <Button Content="OK" Click="OKButton_Click" IsDefault="True" Style="{StaticResource btnFunc}" Width="70"  Margin="0 0 0 5"/>
                </WrapPanel>
            </WrapPanel>
        </StackPanel>
    </Border>
</Window>

后台代码如下：

public partial class KeyboardControl : Window
{
    private int TextIndex { get; set; }
    public string TextStr { get; private set; }//通过该属性，访问Keyboard的文本

    public KeyboardControl(string inputStr)//构造方式传入初始文本
    {
        InitializeComponent();

        TextStr = inputStr;
        tbValue.Text = inputStr;
        tbValue.Focus();
        tbValue.CaretIndex = inputStr.Length;
    }

    public static readonly DependencyProperty CapsProperty = DependencyProperty.Register(
       "Caps", typeof(bool), typeof(KeyboardControl), new PropertyMetadata(default(bool)));
    public bool Caps
    {
        get { return (bool)GetValue(CapsProperty); }
        set { SetValue(CapsProperty, value); }
    }

    private void Button_Click(object sender, RoutedEventArgs e)
    {
        Button button = (Button)sender;
        if (TextIndex == 0)
        {
            tbValue.Text += (string)button.Content;
        }
        else
        {
            tbValue.Text = tbValue.Text.Insert(TextIndex, (string)button.Content);
        }
    }

    private void tbValue_TextChanged(object sender, RoutedEventArgs e)
    {
        TextBox textBox = (TextBox)sender;
        TextIndex = textBox.CaretIndex;
    }

    private void ClearButton_Click(object sender, RoutedEventArgs e)
    {
        tbValue.Text = "";
    }

    private void DELButton_Click(object sender, RoutedEventArgs e)
    {
        if (tbValue.Text.Length > 0)
        {
            if (TextIndex == 0 && tbValue.Text.Length >= 1)
            {
                tbValue.Text = tbValue.Text.Remove(tbValue.Text.Length - 1, 1);
            }
            else if (TextIndex > 0)
            {
                tbValue.Text = tbValue.Text.Remove(TextIndex - 1, 1);
            }
        }
    }

    private void OKButton_Click(object sender, RoutedEventArgs e)
    {
        TextStr = tbValue.Text;
        DialogResult = true;
        Close();
    }

    private void CancelButton_Click(object sender, RoutedEventArgs e)
    {
        DialogResult = false;
        Close();
    }

    private void CapsButton_Click(object sender, RoutedEventArgs e)
    {
        Caps = !Caps;
    }
}

Xaml代码中用到了一个大小写的转换类：

public class CapsConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        if (parameter == null)
        {
            return "";
        }

        if (value == null)
        {
            return parameter.ToString();
        }

        if (value is bool b)
        {
            return b ? parameter.ToString().ToUpper() : parameter.ToString().ToLower();
        }
        else
        {
            return parameter.ToString();
        }
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

三 TouchTextBox

定义一个TouchTextBox的分部类。

public partial class TouchTextBox
{
    private Control hostControl;

    //OnClick方法调用时，通过Window.ShowDialog方法，打开KeyboardControl
    public void OnClick(object sender, MouseButtonEventArgs e)
    {
        if (sender is TextBox textBox)
        {
            hostControl = textBox;
            //计算KeyboardControl的位置，弹出KeyboardControl
            var text = Show(textBox.Text, textBox);
            //KeyboardControl关闭后，获取其文本值，赋值给TextBox
            if (!string.IsNullOrEmpty(text))
            {
                textBox.Text = text;
            }
            else
            {
                textBox.Text = string.Empty;
            }
        }
    }

    private string Show(string initValue, object sender = null)
    {
        var keyboard = new KeyboardControl(initValue);

        SetPosition(keyboard);

        bool result = keyboard.ShowDialog().Value;
        if (result)
        {
            return keyboard.TextStr;
        }
        else
        {
            return string.Empty;
        }
    }

    private void SetPosition(Window window)
    {
        Point point = hostControl.PointFromScreen(new Point(0.0, 0.0));
        double width = SystemParameters.WorkArea.Width;
        double height = SystemParameters.WorkArea.Height;
        if (-point.Y + hostControl.ActualHeight + 5.0 + window.Height < height)
        {
            window.Top = -point.Y + hostControl.ActualHeight + 5.0;
        }
        else
        {
            window.Top = -point.Y - window.Height - 5.0;
        }
        if (-point.X + window.Width < width)
        {
            window.Left = -point.X;
        }
        else
        {
            window.Left = -point.X - (window.Width - hostControl.ActualWidth);
        }
    }
}

添加一个名为TouchTextBox的资源字典。

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                    x:Class="WpfApp1.TouchTextBox">
    <Style x:Key="TouchTextBox" TargetType="{x:Type TextBox}">
        <EventSetter Event="PreviewMouseLeftButtonDown" Handler="OnClick" />
    </Style>
</ResourceDictionary>

四 效果展示

在App.Xaml中引入TouchTextBox.Xaml资源。

<Application x:Class="WpfApp1.App"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:local="clr-namespace:WpfApp1"
             StartupUri="MainWindow.xaml">
    <Application.Resources>
        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                <ResourceDictionary Source="/WpfApp1;component/TouchTextBox.xaml" />
            </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>
    </Application.Resources>
</Application>

MainWindow界面代码：

<Window x:Class="WpfApp1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        mc:Ignorable="d"
        Title="MainWindow" Height="800" Width="1200">
    <StackPanel>
        <TextBox Text="Pop up the keyboard after touching" Width="400" HorizontalAlignment="Left" 
　　　　　　　　　　FontSize="18" Margin="20,20"
                 Style="{StaticResource TouchTextBox}"/>
    </StackPanel>
</Window>

设置TextBox的Style为TouchTextBox，则该TextBox实现了自带触控键盘的效果。

以上。