C# WPF TextBox扩展无法使用MahApps TextBoxHelper

我有一个扩展的wpf文本框，我想使用MahApps TextBoxHelper添加水印。使用普通的文本框工作得很好，但当我尝试用扩展的文本框替换它们时，水印随着Metro风格消失了。“我的扩展文本框”旨在与自定义触摸键盘配合使用，它有许多事件用于处理此功能：

XAML：

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这个问题。根据该解决方案，我需要添加一个基于TextBox的样式，因此以下是我在资源字典中的内容：

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

---

这有点吓人，但很管用

我认为您需要将此

附加属性

添加到

文本框

以显示水印

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

带有

文本框的完整代码

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

---

希望这能有所帮助。

与创建自定义控件不同，您应该创建一个DependencyProperty，类似于TextBoxHelper将事件添加到普通文本框中的方式。这也将消除对样式的需要。

我的TouchTextBox的每个实例实际上都是这样做的。我编辑了这篇文章以包含TouchTextBox的实例。问题是，虽然TextBoxHelper可以处理常规文本框，但当我尝试使用自定义TouchTextBox控件时，它会中断。没有错误，当我从TextBox更改为TouchTextBox时，我的水印消失了。听起来不错，我应该在哪里添加DependencyProperties？你能提供一些参考资料或例子吗？请查看并仅供参考，TextBoxHelper源代码位于感谢你的帮助Joel！这需要一些努力，我不知道这是否是最好的方法，但我已经实现了我自己的TouchTextBoxHelper！

<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}"/>

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;
    }
}

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

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