优化更新代码，添加界面功能并整合

WPFluent/Controls/TextBox/TextBox.cs

@@ -0,0 +1,281 @@
+
+
+
+using WPFluent.Input;
+
+using System.Diagnostics;
+using System.Windows.Controls;
+
+// ReSharper disable once CheckNamespace
+namespace WPFluent.Controls;
+
+/// <summary>
+/// Extended <see cref="System.Windows.Controls"/> with additional parameters like <see cref="PlaceholderText"/>.
+/// </summary>
+public class TextBox : System.Windows.Controls.TextBox
+{
+    /// <summary>
+    /// Identifies the <see cref="ClearButtonEnabled"/> dependency property.
+    /// </summary>
+    public static readonly DependencyProperty ClearButtonEnabledProperty = DependencyProperty.Register(
+        nameof(ClearButtonEnabled),
+        typeof(bool),
+        typeof(TextBox),
+        new PropertyMetadata(true));
+
+    /// <summary>
+    /// Identifies the <see cref="CurrentPlaceholderEnabled"/> dependency property.
+    /// </summary>
+    public static readonly DependencyProperty CurrentPlaceholderEnabledProperty = DependencyProperty.Register(
+        nameof(CurrentPlaceholderEnabled),
+        typeof(bool),
+        typeof(TextBox),
+        new PropertyMetadata(true));
+
+    /// <summary>
+    /// Identifies the <see cref="IconPlacement"/> dependency property.
+    /// </summary>
+    public static readonly DependencyProperty IconPlacementProperty = DependencyProperty.Register(
+        nameof(IconPlacement),
+        typeof(ElementPlacement),
+        typeof(TextBox),
+        new PropertyMetadata(ElementPlacement.Left));
+    /// <summary>
+    /// Identifies the <see cref="Icon"/> dependency property.
+    /// </summary>
+    public static readonly DependencyProperty IconProperty = DependencyProperty.Register(
+        nameof(Icon),
+        typeof(IconElement),
+        typeof(TextBox),
+        new PropertyMetadata(null, null, IconElement.Coerce));
+
+    /// <summary>
+    /// Identifies the <see cref="IsTextSelectionEnabled"/> dependency property.
+    /// </summary>
+    public static readonly DependencyProperty IsTextSelectionEnabledProperty = DependencyProperty.Register(
+        nameof(IsTextSelectionEnabled),
+        typeof(bool),
+        typeof(TextBox),
+        new PropertyMetadata(false));
+
+    /// <summary>
+    /// Identifies the <see cref="PlaceholderEnabled"/> dependency property.
+    /// </summary>
+    public static readonly DependencyProperty PlaceholderEnabledProperty = DependencyProperty.Register(
+        nameof(PlaceholderEnabled),
+        typeof(bool),
+        typeof(TextBox),
+        new PropertyMetadata(true, OnPlaceholderEnabledChanged));
+
+    /// <summary>
+    /// Identifies the <see cref="PlaceholderText"/> dependency property.
+    /// </summary>
+    public static readonly DependencyProperty PlaceholderTextProperty = DependencyProperty.Register(
+        nameof(PlaceholderText),
+        typeof(string),
+        typeof(TextBox),
+        new PropertyMetadata(string.Empty));
+
+    /// <summary>
+    /// Identifies the <see cref="ShowClearButton"/> dependency property.
+    /// </summary>
+    public static readonly DependencyProperty ShowClearButtonProperty = DependencyProperty.Register(
+        nameof(ShowClearButton),
+        typeof(bool),
+        typeof(TextBox),
+        new PropertyMetadata(false));
+
+    /// <summary>
+    /// Identifies the <see cref="TemplateButtonCommand"/> dependency property.
+    /// </summary>
+    public static readonly DependencyProperty TemplateButtonCommandProperty = DependencyProperty.Register(
+        nameof(TemplateButtonCommand),
+        typeof(IRelayCommand),
+        typeof(TextBox),
+        new PropertyMetadata(null));
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="TextBox"/> class.
+    /// </summary>
+    public TextBox()
+    {
+        SetValue(TemplateButtonCommandProperty, new RelayCommand<string>(OnTemplateButtonClick));
+        CurrentPlaceholderEnabled = PlaceholderEnabled;
+    }
+
+    private static void OnPlaceholderEnabledChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
+    {
+        if(d is not TextBox control)
+        {
+            return;
+        }
+
+        control.OnPlaceholderEnabledChanged();
+    }
+
+    /// <summary>
+    /// Hides the clear button by <see cref="ShowClearButton"/> property.
+    /// </summary>
+    protected void HideClearButton()
+    {
+        if(ClearButtonEnabled && !IsKeyboardFocusWithin && ShowClearButton)
+        {
+            SetCurrentValue(ShowClearButtonProperty, false);
+        }
+    }
+
+    /// <summary>
+    /// Triggered when the user clicks the clear text button.
+    /// </summary>
+    protected virtual void OnClearButtonClick()
+    {
+        if(Text.Length > 0)
+        {
+            SetCurrentValue(TextProperty, string.Empty);
+        }
+    }
+
+    /// <inheritdoc/>
+    protected override void OnGotFocus(RoutedEventArgs e)
+    {
+        base.OnGotFocus(e);
+
+        CaretIndex = Text.Length;
+
+        RevealClearButton();
+    }
+
+    /// <inheritdoc/>
+    protected override void OnLostFocus(RoutedEventArgs e)
+    {
+        base.OnLostFocus(e);
+
+        HideClearButton();
+    }
+
+    protected virtual void OnPlaceholderEnabledChanged() { SetPlaceholderTextVisibility(); }
+
+    /// <summary>
+    /// Triggered by clicking a button in the control template.
+    /// </summary>
+    protected virtual void OnTemplateButtonClick(string? parameter)
+    {
+        Debug.WriteLine($"INFO: {typeof(TextBox)} button clicked", "WPFluent");
+
+        OnClearButtonClick();
+    }
+
+    /// <inheritdoc/>
+    protected override void OnTextChanged(TextChangedEventArgs e)
+    {
+        base.OnTextChanged(e);
+
+        SetPlaceholderTextVisibility();
+
+        RevealClearButton();
+    }
+
+    /// <summary>
+    /// Reveals the clear button by <see cref="ShowClearButton"/> property.
+    /// </summary>
+    protected void RevealClearButton()
+    {
+        if(ClearButtonEnabled && IsKeyboardFocusWithin)
+        {
+            SetCurrentValue(ShowClearButtonProperty, Text.Length > 0);
+        }
+    }
+
+    protected void SetPlaceholderTextVisibility()
+    {
+        if(PlaceholderEnabled)
+        {
+            if(CurrentPlaceholderEnabled && Text.Length > 0)
+            {
+                SetCurrentValue(CurrentPlaceholderEnabledProperty, false);
+            }
+
+            if(!CurrentPlaceholderEnabled && Text.Length < 1)
+            {
+                SetCurrentValue(CurrentPlaceholderEnabledProperty, true);
+            }
+        }
+        else if(CurrentPlaceholderEnabled)
+        {
+            SetCurrentValue(CurrentPlaceholderEnabledProperty, false);
+        }
+    }
+
+    /// <summary>
+    /// Gets or sets a value indicating whether to enable the clear button.
+    /// </summary>
+    public bool ClearButtonEnabled
+    {
+        get => (bool)GetValue(ClearButtonEnabledProperty);
+        set => SetValue(ClearButtonEnabledProperty, value);
+    }
+
+    /// <summary>
+    /// Gets or sets a value indicating whether to display the placeholder text.
+    /// </summary>
+    public bool CurrentPlaceholderEnabled
+    {
+        get => (bool)GetValue(CurrentPlaceholderEnabledProperty);
+        protected set => SetValue(CurrentPlaceholderEnabledProperty, value);
+    }
+
+    /// <summary>
+    /// Gets or sets displayed <see cref="IconElement"/>.
+    /// </summary>
+    public IconElement? Icon { get => (IconElement?)GetValue(IconProperty); set => SetValue(IconProperty, value); }
+
+    /// <summary>
+    /// Gets or sets which side the icon should be placed on.
+    /// </summary>
+    public ElementPlacement IconPlacement
+    {
+        get => (ElementPlacement)GetValue(IconPlacementProperty);
+        set => SetValue(IconPlacementProperty, value);
+    }
+
+    /// <summary>
+    /// Gets or sets a value indicating whether text selection is enabled.
+    /// </summary>
+    public bool IsTextSelectionEnabled
+    {
+        get => (bool)GetValue(IsTextSelectionEnabledProperty);
+        set => SetValue(IsTextSelectionEnabledProperty, value);
+    }
+
+    /// <summary>
+    /// Gets or sets a value indicating whether to enable the placeholder text.
+    /// </summary>
+    public bool PlaceholderEnabled
+    {
+        get => (bool)GetValue(PlaceholderEnabledProperty);
+        set => SetValue(PlaceholderEnabledProperty, value);
+    }
+
+    /// <summary>
+    /// Gets or sets placeholder text.
+    /// </summary>
+    public string PlaceholderText
+    {
+        get => (string)GetValue(PlaceholderTextProperty);
+        set => SetValue(PlaceholderTextProperty, value);
+    }
+
+    /// <summary>
+    /// Gets or sets a value indicating whether to show the clear button when <see cref="TextBox"/> is focused.
+    /// </summary>
+    public bool ShowClearButton
+    {
+        get => (bool)GetValue(ShowClearButtonProperty);
+        protected set => SetValue(ShowClearButtonProperty, value);
+    }
+
+    /// <summary>
+    /// Gets the command triggered when clicking the button.
+    /// </summary>
+    public IRelayCommand TemplateButtonCommand => (IRelayCommand)GetValue(TemplateButtonCommandProperty);
+}