ShrlAlgoToolkit/NeuWPF/NeoUI/Assists/InputAssist.cs

using System.Windows.Controls.Primitives;

using NeumUI.Extensions;

namespace NeumUI.Assists;

/// <summary>
/// InputAssist 类提供了一系列附加属性，用于增强 WPF 应用程序中输入控件的功能。这些功能包括设置占位符文本、占位符颜色、前缀和后缀内容等，支持 TextBoxBase、PasswordBox 和 ComboBox 控件。
/// </summary>
public static class InputAssist
{
    #region Attached Properties

    /// <summary>
    /// 用于设置或获取控件的占位符文本。
    /// </summary>
    public static readonly DependencyProperty PlaceholderProperty =
        DependencyProperty.RegisterAttached("Placeholder", typeof(string), typeof(InputAssist), new PropertyMetadata(string.Empty));

    /// <summary>
    /// Gets the placeholder for the input control.
    /// </summary>
    [AttachedPropertyBrowsableForType(typeof(TextBoxBase))]
    [AttachedPropertyBrowsableForType(typeof(PasswordBox))]
    [AttachedPropertyBrowsableForType(typeof(ComboBox))]
    public static string GetPlaceholder(DependencyObject obj)
    {
        return (string)obj.GetValue(PlaceholderProperty);
    }

    /// <summary>
    /// 设置输入控件的占位符。
    /// </summary>
    /// <param name="obj">要设置占位符的依赖对象。</param>
    /// <param name="value">占位符的文本值。</param>
    public static void SetPlaceholder(DependencyObject obj, string value)
    {
        obj.SetValue(PlaceholderProperty, value);
    }

    /// <summary>
    /// 用于设置或获取占位符文本的颜色刷。
    /// </summary>
    public static readonly DependencyProperty PlaceholderBrushProperty =
        DependencyProperty.RegisterAttached("PlaceholderBrush", typeof(Brush), typeof(InputAssist),
            new FrameworkPropertyMetadata(
                Brushes.Silver,
                FrameworkPropertyMetadataOptions.AffectsRender |
                FrameworkPropertyMetadataOptions.SubPropertiesDoNotAffectRender |
                FrameworkPropertyMetadataOptions.Inherits));

    /// <summary>
    /// Gets the placeholder foreground brush for the input control.
    /// </summary>
    [AttachedPropertyBrowsableForType(typeof(TextBoxBase))]
    [AttachedPropertyBrowsableForType(typeof(PasswordBox))]
    [AttachedPropertyBrowsableForType(typeof(ComboBox))]
    public static Brush GetPlaceholderBrush(DependencyObject obj)
    {
        return (Brush)obj.GetValue(PlaceholderBrushProperty);
    }

    /// <summary>
    /// 设置输入控件的占位符画刷。
    /// </summary>
    /// <param name="obj">依赖对象，通常为TextBoxBase、PasswordBox或ComboBox。</param>
    /// <param name="value">要设置的占位符画刷。</param>
    public static void SetPlaceholderBrush(DependencyObject obj, Brush value)
    {
        obj.SetValue(PlaceholderBrushProperty, value);
    }

    /// <summary>
    /// 用于设置或获取控件的前缀内容。
    /// </summary>
    public static readonly DependencyProperty PrefixProperty =
        DependencyProperty.RegisterAttached("Prefix", typeof(object), typeof(InputAssist), new PropertyMetadata(null));

    /// <summary>
    /// 获取与指定依赖对象关联的前缀。
    /// </summary>
    /// <param name="obj">要获取前缀的依赖对象。</param>
    /// <returns>与指定依赖对象关联的前缀对象。</returns>
    [AttachedPropertyBrowsableForType(typeof(TextBox))]
    [AttachedPropertyBrowsableForType(typeof(PasswordBox))]
    [AttachedPropertyBrowsableForType(typeof(ComboBox))]
    public static object GetPrefix(DependencyObject obj)
    {
        return obj.GetValue(PrefixProperty);
    }

    /// <summary>
    /// 设置输入控件的前缀。
    /// </summary>
    /// <param name="obj">要设置前缀的依赖对象。</param>
    /// <param name="value">要设置为前缀的对象。</param>
    public static void SetPrefix(DependencyObject obj, object value)
    {
        obj.SetValue(PrefixProperty, value);
    }
    // 这是一个只读的依赖属性，用于向XAML报告PasswordBox是否有文本。
    // 只有这个类内部可以通过Key来修改它的值，保证了状态的可靠性。
    private static readonly DependencyPropertyKey HasTextPropertyKey =
        DependencyProperty.RegisterAttachedReadOnly(
            "HasPassword",
            typeof(bool),
            typeof(InputAssist),
            new PropertyMetadata(false));

    public static readonly DependencyProperty HasPasswordProperty = HasTextPropertyKey.DependencyProperty;

    [AttachedPropertyBrowsableForType(typeof(PasswordBox))]
    public static bool GetHasPassword(DependencyObject obj)
    {
        return (bool)obj.GetValue(HasPasswordProperty);
    }
 

    // 核心更新逻辑
    private static void UpdateHasPassword(PasswordBox passwordBox)
    {
        // 根据密码长度是否大于0，来设置HasText属性的值
        passwordBox.SetValue(HasTextPropertyKey, passwordBox.Password.Length > 0);
    }
    /// <summary>
    /// 用于设置或获取附着到控件上的后缀内容。
    /// </summary>
    public static readonly DependencyProperty SuffixProperty =
        DependencyProperty.RegisterAttached("Suffix", typeof(object), typeof(InputAssist), new PropertyMetadata(null));

    /// <summary>
    /// Gets the suffix object of the input control.
    /// </summary>
    [AttachedPropertyBrowsableForType(typeof(TextBox))]
    [AttachedPropertyBrowsableForType(typeof(PasswordBox))]
    public static object GetSuffix(DependencyObject obj)
    {
        return obj.GetValue(SuffixProperty);
    }

    /// <summary>
    /// 设置输入控件的后缀。
    /// </summary>
    /// <param name="obj">要设置后缀的依赖对象。</param>
    /// <param name="value">要设置为后缀的对象。</param>
    public static void SetSuffix(DependencyObject obj, object value)
    {
        obj.SetValue(SuffixProperty, value);
    }

    /// <summary>
    /// 用于设置或获取控件的密码文本。
    /// </summary>
    public static readonly DependencyProperty PasswordProperty =
        DependencyProperty.RegisterAttached("Password", typeof(string), typeof(InputAssist),
            new FrameworkPropertyMetadata(string.Empty, FrameworkPropertyMetadataOptions.BindsTwoWayByDefault, OnPasswordChanged));

    private static void OnPasswordChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        if (d is PasswordBox passwordBox)
        {
            // 解除再绑定，防止重复订阅
            passwordBox.PasswordChanged -= PasswordBox_PasswordChanged;

            var newVal = (string)e.NewValue ?? string.Empty;
            if (passwordBox.Password != newVal)
            {
                passwordBox.Password = newVal;
            }

            // 确保监听用户输入
            passwordBox.PasswordChanged += PasswordBox_PasswordChanged;
        }
    }

    private static void PasswordBox_PasswordChanged(object sender, RoutedEventArgs e)
    {
        if (sender is not PasswordBox box) return;
        var attached = GetPassword(box);
        var actual = box.Password;

        // 当用户输入变化时同步回附加属性
        if (attached != actual)
        {
            // 这里调用 SetPassword 会再次触发 OnPasswordChanged，但因值相同不会再写入造成循环
            SetPassword(box, actual);
        }
        UpdateHasPassword(box);
    }

    /// <summary>
    /// Gets the password currently held by the PasswordBox.
    /// </summary>
    [AttachedPropertyBrowsableForType(typeof(PasswordBox))]
    public static string GetPassword(DependencyObject obj)
    {
        return (string)obj.GetValue(PasswordProperty);
    }

    /// <summary>
    /// Sets the password currently held by the PasswordBox.
    /// </summary>
    public static void SetPassword(DependencyObject obj, string value)
    {
        obj.SetValue(PasswordProperty, value);
    }

    /// <summary>
    /// 切换可见密码的样板的作用
    /// </summary>
    public static readonly DependencyProperty EyeableProperty =
        DependencyProperty.RegisterAttached("Eyeable", typeof(bool), typeof(InputAssist), new PropertyMetadata(false));

    /// <summary>
    /// Gets whether the password currently held by PasswordBox is displayed in text.
    /// </summary>
    [AttachedPropertyBrowsableForType(typeof(PasswordBox))]
    public static bool GetEyeable(DependencyObject obj)
    {
        return (bool)obj.GetValue(EyeableProperty);
    }

    /// <summary>
    /// 设置是否可以切换密码框的显示模式（显示/隐藏密码）。
    /// </summary>
    /// <param name="obj">依赖对象，通常是PasswordBox。</param>
    /// <param name="value">布尔值，表示是否启用显示/隐藏密码的功能。</param>
    public static void SetEyeable(DependencyObject obj, bool value)
    {
        obj.SetValue(EyeableProperty, value);
    }

    /// <summary>
    /// 用于设置或获取控件是否可以被清空。
    /// </summary>
    public static readonly DependencyProperty ClearEnabledProperty =
        DependencyProperty.RegisterAttached("ClearEnabled", typeof(bool), typeof(InputAssist), new PropertyMetadata(false, OnClearEnabledChanged));

    /// <summary>
    /// Gets the clear enable state of the control.
    /// </summary>
    [AttachedPropertyBrowsableForType(typeof(TextBox))]
    [AttachedPropertyBrowsableForType(typeof(PasswordBox))]
    [AttachedPropertyBrowsableForType(typeof(ComboBox))]
    public static bool GetClearEnabled(DependencyObject obj)
    {
        return (bool)obj.GetValue(ClearEnabledProperty);
    }


    /// <summary>
    /// Sets the clear enable state of the control.
    /// </summary>
    public static void SetClearEnabled(DependencyObject obj, bool value)
    {
        obj.SetValue(ClearEnabledProperty, value);
    }

    private static void OnClearEnabledChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        if (d is not UIElement element) return;
        if ((bool)e.NewValue)
        {
            element.MouseLeftButtonUp += OnClear;
        }
        else
        {
            element.MouseLeftButtonUp -= OnClear;
        }
    }

    public static readonly DependencyProperty ClearableProperty = DependencyProperty.RegisterAttached(
        "Clearable", typeof(bool), typeof(InputAssist), new PropertyMetadata(default(bool)));

    public static void SetClearable(DependencyObject d, bool value)
    {
        d.SetValue(ClearableProperty, value);
    }

    public static bool GetClearable(DependencyObject d)
    {
        return (bool)d.GetValue(ClearableProperty);
    }
    #endregion

    #region Private Methods

    private static void OnClear(object sender, RoutedEventArgs e)
    {
        if (sender is DependencyObject d)
        {
            //var ance = d.GetAncestors();
            var parent = d.GetAncestors().FirstOrDefault(a => a is TextBox || a is PasswordBox || a is ComboBox);
            if (!GetClearable(parent)) return;
            if (parent is TextBox textBox)
            {
                textBox.Clear();
                textBox.GetBindingExpression(TextBox.TextProperty)?.UpdateSource();
            }
            else if (parent is PasswordBox passwordBox)
            {
                passwordBox.Clear();
                passwordBox.GetBindingExpression(PasswordProperty)?.UpdateSource();
            }
            else if (parent is ComboBox)
            {
                if (((ComboBox)parent).IsEditable)
                {
                    ((ComboBox)parent).Text = string.Empty;
                    ((ComboBox)parent).GetBindingExpression(ComboBox.TextProperty)?.UpdateSource();
                }

                ((ComboBox)parent).SelectedItem = null;
                ((ComboBox)parent).GetBindingExpression(Selector.SelectedItemProperty)?.UpdateSource();
            }

            // if (d is TextBox textBox)
             // {
             //     textBox.Clear();
             //     textBox.GetBindingExpression(TextBox.TextProperty)?.UpdateSource();
             // }
             // else if (d is PasswordBox passwordBox)
             // {
             //     passwordBox.Clear();
             //     passwordBox.GetBindingExpression(PasswordProperty)?.UpdateSource();
             // }
             // else if (d is ComboBox comboBox)
             // {
             //     if (comboBox.IsEditable)
             //     {
             //         comboBox.Text = string.Empty;
             //         comboBox.GetBindingExpression(ComboBox.TextProperty)?.UpdateSource();
             //     }
             //
             //     comboBox.SelectedItem = null;
             //     comboBox.GetBindingExpression(Selector.SelectedItemProperty)?.UpdateSource();
             // }
             // else if(d is AutoComplete auto)
             // {
             //     // 如果是 AutoComplete 控件，清空其文本
             //     // 并更新绑定源
             //     auto.Text = string.Empty;
             //     auto.GetBindingExpression(TextBox.TextProperty)?.UpdateSource();
             // }
        }
    }

    #endregion
}