WPF TextBox 扩展无法使用 MahApps TextBoxHelper

Question

我有一个扩展的 wpf 文本框，我想使用 MahApps TextBoxHelper 添加水印。使用常规文本框效果很好，但当我尝试用我的扩展文本框 TouchTextBox 替换它们时，水印与 Metro 风格一起消失了。我的扩展文本框旨在与自定义触摸键盘一起使用，并且它有许多用于处理此功能的事件：

XAML:

<TextBox x:Class="MyNamespaceHERE.TouchTextBox"
     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
     xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
     xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
     xmlns:Controls="clr-namespace:MahApps.Metro.Controls;assembly=MahApps.Metro"
     xmlns:local="clr-namespace:MyNamespaceHERE"
     mc:Ignorable="d" 
     GotFocus="TouchTextBox_GotFocus"
     LostFocus="TouchTextBox_LostFocus">
</TextBox>

隐藏代码：

public partial class TouchTextBox : TextBox
{

    public TouchTextBox()
    {
        InitializeComponent();

    }

    private void TouchTextBox_GotFocus(object sender, RoutedEventArgs e)
    {
        StaticEvents.OnShowTouchKeyboard(sender, e);
        StaticEvents.TouchKeyboardKeyTouch += StaticEvents_TouchKeyboardKeyTouch;
        StaticEvents.TouchKeyboardSpaceTouch += StaticEvents_TouchKeyboardSpaceTouch;
        StaticEvents.TouchKeyboardBackspaceTouch += StaticEvents_TouchKeyboardBackspaceTouch;
    }

    private void StaticEvents_TouchKeyboardBackspaceTouch(object sender, EventArgs e)
    {
        int i = CaretIndex;
        if (CaretIndex == 0) return;
        Text = Text.Remove(CaretIndex - 1, 1);
        CaretIndex = i - 1;
    }

    private void StaticEvents_TouchKeyboardSpaceTouch(object sender, EventArgs e)
    {
        int i = CaretIndex;
        Text = Text.Insert(CaretIndex, " ");
        CaretIndex = i + 1;
    }

    private void StaticEvents_TouchKeyboardKeyTouch(object sender, EventArgs e)
    {
        int i = CaretIndex;
        string t = (sender as Button).Content.ToString();
        Text = Text.Insert(CaretIndex, t);
        CaretIndex = i + 1;
    }

    private void TouchTextBox_LostFocus(object sender, RoutedEventArgs e)
    {
        StaticEvents.OnHideTouchKeyboard(sender, e);
        StaticEvents.TouchKeyboardKeyTouch -= StaticEvents_TouchKeyboardKeyTouch;
        StaticEvents.TouchKeyboardSpaceTouch -= StaticEvents_TouchKeyboardSpaceTouch;
        StaticEvents.TouchKeyboardBackspaceTouch -= StaticEvents_TouchKeyboardBackspaceTouch;
    }
}

我遵循了我在这个解决方案中找到的建议，但到目前为止还没有解决问题。根据解决方案，我需要添加一个基于 TextBox 的样式，所以这是我的资源字典中的内容：

<Style TargetType="local:TouchTextBox" BasedOn="{StaticResource {x:Type TextBox}}" x:Key="TouchTextBoxStyle"/>

我将此样式添加到我的 TouchTextBox 控件的每个实例中，使它们看起来像这样：

<local:TouchTextBox x:Name="UsernameTextBox" Controls:TextBoxHelper.Watermark="Username" Width="200" Text="{Binding Username}" Style="{StaticResource TouchTextBoxStyle}"/>
<local:TouchTextBox x:Name="PasswordTextBox" Controls:TextBoxHelper.Watermark="Password" Width="200" Margin="0,30,0,0" Text="{Binding Password}" Style="{StaticResource TouchTextBoxStyle}"/>

到目前为止还没有运气。如何使用自定义 TouchTextBox 用户控件恢复 MahApps 的 TextBoxHelper 的所有强大功能？非常感谢您提供的任何指导。

编辑：

我采纳了 Joel Lucsy 的建议并实施了 TouchTextBoxHelper class 来处理 DependencyProperty 我的事件处理：

public class TouchTextBoxHelper : DependencyObject
{
    public static readonly DependencyProperty IsTouchKeyboardTargetProperty = DependencyProperty.Register("IsTouchKeyboardTarget", typeof(bool), typeof(TouchTextBoxHelper), new FrameworkPropertyMetadata(false, IsTouchKeyboardTargetChanged));


    [AttachedPropertyBrowsableForType(typeof(TextBox))]
    public static bool GetIsTouchKeyboardTargetEnabled(DependencyObject obj)
    {
        return (bool)obj.GetValue(IsTouchKeyboardTargetProperty);
    }

    [AttachedPropertyBrowsableForType(typeof(TextBox))]
    public static void SetIsTouchKeyboardTargetEnabled(DependencyObject obj, bool value)
    {
        obj.SetValue(IsTouchKeyboardTargetProperty, value);
        TextBox tb = obj as TextBox;
        if (tb == null) return;
        if (value)
        {

            tb.GotFocus += TextBoxBaseGotFocus;
            tb.LostFocus += TextBoxBaseLostFocus;
        }
        else
        {
            tb.GotFocus -= TextBoxBaseGotFocus;
            tb.LostFocus -= TextBoxBaseLostFocus;
        }
    }

    private static void IsTouchKeyboardTargetChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var tb = d as TextBox;
        if (null == tb)
        {
            throw new InvalidOperationException("The property 'IsTouchKeyboardTarget' may only be set on TextBox elements.");
        }

        if (e.OldValue != e.NewValue)
        {
            //tb.SetValue(SpellCheck.IsEnabledProperty, (bool)e.NewValue);
            if ((bool)e.NewValue)
            {
                tb.GotFocus += TextBoxBaseGotFocus;
                tb.LostFocus += TextBoxBaseLostFocus;
            }
            else
            {
                tb.GotFocus -= TextBoxBaseGotFocus;
                tb.LostFocus -= TextBoxBaseLostFocus;
            }
        }
    }

    private static void TextBoxBaseGotFocus(object sender, RoutedEventArgs e)
    {
        TouchTextBoxEvents.tb = sender as TextBox;
        StaticEvents.OnShowTouchKeyboard(sender, e);
        StaticEvents.TouchKeyboardKeyTouch += TouchTextBoxEvents.StaticEvents_TouchKeyboardKeyTouch;
        StaticEvents.TouchKeyboardSpaceTouch += TouchTextBoxEvents.StaticEvents_TouchKeyboardSpaceTouch;
        StaticEvents.TouchKeyboardBackspaceTouch += TouchTextBoxEvents.StaticEvents_TouchKeyboardBackspaceTouch;
    }

    private static void TextBoxBaseLostFocus(object sender, RoutedEventArgs e)
    {
        StaticEvents.OnHideTouchKeyboard(sender, e);
        StaticEvents.TouchKeyboardKeyTouch -= TouchTextBoxEvents.StaticEvents_TouchKeyboardKeyTouch;
        StaticEvents.TouchKeyboardSpaceTouch -= TouchTextBoxEvents.StaticEvents_TouchKeyboardSpaceTouch;
        StaticEvents.TouchKeyboardBackspaceTouch -= TouchTextBoxEvents.StaticEvents_TouchKeyboardBackspaceTouch;
    }
}

public class TouchTextBoxEvents
{
    public static TextBox tb = null;
    public static void StaticEvents_TouchKeyboardKeyTouch(object sender, EventArgs e)
    {
        int i = tb.CaretIndex;
        string t = (sender as Button).Content.ToString();
        tb.Text = tb.Text.Insert(tb.CaretIndex, t);
        tb.CaretIndex = i + 1;
    }

    public static void StaticEvents_TouchKeyboardBackspaceTouch(object sender, EventArgs e)
    {
        int i = tb.CaretIndex;
        if (tb.CaretIndex == 0) return;
        tb.Text = tb.Text.Remove(tb.CaretIndex - 1, 1);
        tb.CaretIndex = i - 1;
    }

    public static void StaticEvents_TouchKeyboardSpaceTouch(object sender, EventArgs e)
    {
        int i = tb.CaretIndex;
        tb.Text = tb.Text.Insert(tb.CaretIndex, " ");
        tb.CaretIndex = i + 1;
    }
}

有点吓人，但确实有效！

Answer 1

我认为您需要将此 Attached Properties 添加到 TextBox 以显示水印。

controls:TextBoxHelper.Watermark="My Watermark" 
controls:TextBoxHelper.UseFloatingWatermark="True" // If Needed.

完整代码 TextBox.

<TextBox Height="40" Width="125" MaxLength="15"  
    controls:TextBoxHelper.Watermark="My Watermark" 
    controls:TextBoxHelper.UseFloatingWatermark="True"/>

希望对您有所帮助。

Answer 2

与其创建自定义控件，不如创建一个 DependencyProperty，类似于 TextBoxHelper 将事件添加到普通 TextBox 的方式。这也将消除对样式的需求。

WPF TextBox 扩展无法使用 MahApps TextBoxHelper

WPF TextBox Extension unable to use MahApps TextBoxHelper

c#

wpf

xaml

mvvm

mahapps.metro