Cleanup: Aligning hint, helper text and validation error based on padding

MainDemo.Wpf/Domain/SmartHintViewModel.cs

@@ -10,14 +10,16 @@ internal class SmartHintViewModel : ViewModelBase
     private bool _showClearButton = true;
     private bool _showLeadingIcon = true;
     private string _hintText = "Hint text";
-    private Point _selectedFloatingOffset = new (0, -16);
+    private string _helperText = "Helper text";
+    private Point _selectedFloatingOffset = new(0, -16);
+    private bool _applyCustomPadding;
+    private Thickness _selectedCustomPadding = new(5);
 
     public IEnumerable<FloatingHintHorizontalAlignment> HorizontalAlignmentOptions { get; } = Enum.GetValues(typeof(FloatingHintHorizontalAlignment)).OfType<FloatingHintHorizontalAlignment>();
     public IEnumerable<double> FloatingScaleOptions { get; } = new[] {0.25, 0.5, 0.75, 1.0};
-
     public IEnumerable<Point> FloatingOffsetOptions { get; } = new[] { new Point(0, -16), new Point(0, 16), new Point(16, 16), new Point(-16, -16) };
-
     public IEnumerable<string> ComboBoxOptions { get; } = new[] {"Option 1", "Option 2", "Option 3"};
+    public IEnumerable<Thickness> CustomPaddingOptions { get; } = new [] { new Thickness(0), new Thickness(5), new Thickness(10), new Thickness(15) };
 
     public bool FloatHint
     {
@@ -88,4 +90,34 @@ public string HintText
             OnPropertyChanged();
         }
     }
+
+    public string HelperText
+    {
+        get => _helperText;
+        set
+        {
+            _helperText = value;
+            OnPropertyChanged();
+        }
+    }
+
+    public bool ApplyCustomPadding
+    {
+        get => _applyCustomPadding;
+        set
+        {
+            _applyCustomPadding = value;
+            OnPropertyChanged();
+        }
+    }
+
+    public Thickness SelectedCustomPadding
+    {
+        get => _selectedCustomPadding;
+        set
+        {
+            _selectedCustomPadding = value;
+            OnPropertyChanged();
+        }
+    }
 }

MainDemo.Wpf/SmartHint.xaml.cs

@@ -1,4 +1,8 @@
-using MaterialDesignDemo.Domain;
+using System.Globalization;
+using System.Windows.Data;
+using System.Windows.Media;
+using MaterialDesignDemo.Domain;
+using MaterialDesignThemes.Wpf;
 
 namespace MaterialDesignDemo;
 
@@ -7,9 +11,89 @@ namespace MaterialDesignDemo;
 /// </summary>
 public partial class SmartHint : UserControl
 {
+    // Attached property used for binding in the RichTextBox to enable triggering of validation errors.
+    internal static readonly DependencyProperty RichTextBoxTextProperty = DependencyProperty.RegisterAttached(
+        "RichTextBoxText", typeof(object), typeof(SmartHint), new PropertyMetadata(null));
+    internal static void SetRichTextBoxText(DependencyObject element, object value) => element.SetValue(RichTextBoxTextProperty, value);
+    internal static object GetRichTextBoxText(DependencyObject element) => element.GetValue(RichTextBoxTextProperty);
+
     public SmartHint()
     {
         DataContext = new SmartHintViewModel();
         InitializeComponent();
     }
+
+    private void HasErrors_OnToggled(object sender, RoutedEventArgs e)
+    {
+        CheckBox c = (CheckBox) sender;
+
+        foreach (FrameworkElement element in FindVisualChildren<FrameworkElement>(ControlsPanel))
+        {
+            var binding = GetBinding(element);
+            if (binding is null)
+                continue;
+
+            if (c.IsChecked.GetValueOrDefault(false))
+            {
+                var error = new ValidationError(new ExceptionValidationRule(), binding)
+                {
+                    ErrorContent = "Invalid input, please fix it!"
+                };
+                Validation.MarkInvalid(binding, error);
+            }
+            else
+            {
+                Validation.ClearInvalid(binding);
+            }
+        }
+    }
+
+    private static BindingExpression? GetBinding(FrameworkElement element)
+    {
+        if (element is TextBox textBox)
+            return textBox.GetBindingExpression(TextBox.TextProperty);
+        if (element is RichTextBox richTextBox)
+            return richTextBox.GetBindingExpression(RichTextBoxTextProperty);
+        if (element is PasswordBox passwordBox)
+            return passwordBox.GetBindingExpression(PasswordBoxAssist.PasswordProperty);
+        if (element is ComboBox comboBox)
+            return comboBox.GetBindingExpression(ComboBox.TextProperty);
+        if (element is DatePicker datePicker)
+            return datePicker.GetBindingExpression(DatePicker.TextProperty);
+        if (element is TimePicker timePicker)
+            return timePicker.GetBindingExpression(TimePicker.TextProperty);
+        return default;
+    }
+
+    private static IEnumerable<T> FindVisualChildren<T>(DependencyObject? dependencyObject) where T : DependencyObject
+    {
+        if (dependencyObject is null)
+            yield break;
+
+        if (dependencyObject is T obj)
+            yield return obj;
+
+        for (int i = 0; i < VisualTreeHelper.GetChildrenCount(dependencyObject); i++)
+        {
+            DependencyObject child = VisualTreeHelper.GetChild(dependencyObject, i);
+            foreach (T childOfChild in FindVisualChildren<T>(child))
+            {
+                yield return childOfChild;
+            }
+        }
+    }
+}
+
+internal class CustomPaddingConverter : IMultiValueConverter
+{
+    public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
+    {
+        Thickness? defaultPadding = values[0] as Thickness?;
+        bool applyCustomPadding = (bool) values[1];
+        Thickness customPadding = (Thickness) values[2];
+        return applyCustomPadding ? customPadding : defaultPadding ?? DependencyProperty.UnsetValue;
+    }
+
+    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
+        => throw new NotImplementedException();
 }

MaterialDesignThemes.UITests/WPF/ComboBoxes/ComboBoxTests.cs

@@ -1,4 +1,5 @@
 using System.ComponentModel;
+using MaterialDesignThemes.UITests.WPF.TextBoxes;
 
 namespace MaterialDesignThemes.UITests.WPF.ComboBoxes;
 
@@ -166,4 +167,94 @@ public async Task OnEditableComboBox_ClickInTextArea_FocusesTextBox()
 
         recorder.Success();
     }
+
+    [Theory]
+    [InlineData("MaterialDesignFloatingHintComboBox", null)]
+    [InlineData("MaterialDesignFloatingHintComboBox", 5)]
+    [InlineData("MaterialDesignFloatingHintComboBox", 20)]
+    [InlineData("MaterialDesignFilledComboBox", null)]
+    [InlineData("MaterialDesignFilledComboBox", 5)]
+    [InlineData("MaterialDesignFilledComboBox", 20)]
+    [InlineData("MaterialDesignOutlinedComboBox", null)]
+    [InlineData("MaterialDesignOutlinedComboBox", 5)]
+    [InlineData("MaterialDesignOutlinedComboBox", 20)]
+    public async Task ComboBox_WithHintAndHelperText_RespectsPadding(string styleName, int? padding)
+    {
+        await using var recorder = new TestRecorder(App);
+
+        // FIXME: Tolerance needed because TextFieldAssist.TextBoxViewMargin is in play and slightly modifies the hint text placement in certain cases.
+        const double tolerance = 1.5;
+
+        string styleAttribute = $"Style=\"{{StaticResource {styleName}}}\"";
+        string paddingAttribute = padding.HasValue ? $"Padding=\"{padding.Value}\"" : string.Empty;
+
+        var comboBox = await LoadXaml<ComboBox>($@"
+<ComboBox {styleAttribute} {paddingAttribute}
+  materialDesign:HintAssist.Hint=""Hint text""
+  materialDesign:HintAssist.HelperText=""Helper text""
+  Width=""200"" VerticalAlignment=""Center"" HorizontalAlignment=""Center"" />
+");
+
+        var contentHost = await comboBox.GetElement<ScrollViewer>("PART_ContentHost");
+        var hint = await comboBox.GetElement<SmartHint>("Hint");
+        var helperText = await comboBox.GetElement<TextBlock>("HelperTextTextBlock");
+
+        Rect? contentHostCoordinates = await contentHost.GetCoordinates();
+        Rect? hintCoordinates = await hint.GetCoordinates();
+        Rect? helperTextCoordinates = await helperText.GetCoordinates();
+
+        Assert.InRange(Math.Abs(contentHostCoordinates.Value.Left - hintCoordinates.Value.Left), 0, tolerance);
+        Assert.InRange(Math.Abs(contentHostCoordinates.Value.Left - helperTextCoordinates.Value.Left), 0, tolerance);
+
+        recorder.Success();
+    }
+
+    [Theory]
+    [InlineData("MaterialDesignFloatingHintComboBox", null)]
+    [InlineData("MaterialDesignFloatingHintComboBox", 5)]
+    [InlineData("MaterialDesignFloatingHintComboBox", 20)]
+    [InlineData("MaterialDesignFilledComboBox", null)]
+    [InlineData("MaterialDesignFilledComboBox", 5)]
+    [InlineData("MaterialDesignFilledComboBox", 20)]
+    [InlineData("MaterialDesignOutlinedComboBox", null)]
+    [InlineData("MaterialDesignOutlinedComboBox", 5)]
+    [InlineData("MaterialDesignOutlinedComboBox", 20)]
+    public async Task ComboBox_WithHintAndValidationError_RespectsPadding(string styleName, int? padding)
+    {
+        await using var recorder = new TestRecorder(App);
+
+        // FIXME: Tolerance needed because TextFieldAssist.TextBoxViewMargin is in play and slightly modifies the hint text placement in certain cases.
+        const double tolerance = 1.5;
+
+        string styleAttribute = $"Style=\"{{StaticResource {styleName}}}\"";
+        string paddingAttribute = padding.HasValue ? $"Padding=\"{padding.Value}\"" : string.Empty;
+
+        var comboBox = await LoadXaml<ComboBox>($@"
+<ComboBox {styleAttribute} {paddingAttribute}
+  materialDesign:HintAssist.Hint=""Hint text""
+  materialDesign:HintAssist.HelperText=""Helper text""
+  Width=""200"" VerticalAlignment=""Center"" HorizontalAlignment=""Center"">
+  <ComboBox.Text>
+    <Binding RelativeSource=""{{RelativeSource Self}}"" Path=""Tag"" UpdateSourceTrigger=""PropertyChanged"">
+      <Binding.ValidationRules>
+        <local:NotEmptyValidationRule ValidatesOnTargetUpdated=""True""/>
+      </Binding.ValidationRules>
+    </Binding>
+  </ComboBox.Text>
+</ComboBox>
+", ("local", typeof(NotEmptyValidationRule)));
+
+        var contentHost = await comboBox.GetElement<ScrollViewer>("PART_ContentHost");
+        var hint = await comboBox.GetElement<SmartHint>("Hint");
+        var errorViewer = await comboBox.GetElement<Border>("DefaultErrorViewer");
+
+        Rect? contentHostCoordinates = await contentHost.GetCoordinates();
+        Rect? hintCoordinates = await hint.GetCoordinates();
+        Rect? errorViewerCoordinates = await errorViewer.GetCoordinates();
+
+        Assert.InRange(Math.Abs(contentHostCoordinates.Value.Left - hintCoordinates.Value.Left), 0, tolerance);
+        Assert.InRange(Math.Abs(contentHostCoordinates.Value.Left - errorViewerCoordinates.Value.Left), 0, tolerance);
+
+        recorder.Success();
+    }
 }

MaterialDesignThemes.UITests/WPF/DatePickers/DatePickerTests.cs

@@ -1,5 +1,6 @@
 using System.ComponentModel;
 using System.Globalization;
+using MaterialDesignThemes.UITests.WPF.TextBoxes;
 
 namespace MaterialDesignThemes.UITests.WPF.DatePickers;
 
@@ -112,6 +113,96 @@ public async Task OutlinedDatePicker_RespectsActiveAndInactiveBorderThickness_Wh
 
         recorder.Success();
     }
+
+    [Theory]
+    [InlineData("MaterialDesignFloatingHintDatePicker", null)]
+    [InlineData("MaterialDesignFloatingHintDatePicker", 5)]
+    [InlineData("MaterialDesignFloatingHintDatePicker", 20)]
+    [InlineData("MaterialDesignFilledDatePicker", null)]
+    [InlineData("MaterialDesignFilledDatePicker", 5)]
+    [InlineData("MaterialDesignFilledDatePicker", 20)]
+    [InlineData("MaterialDesignOutlinedDatePicker", null)]
+    [InlineData("MaterialDesignOutlinedDatePicker", 5)]
+    [InlineData("MaterialDesignOutlinedDatePicker", 20)]
+    public async Task DatePicker_WithHintAndHelperText_RespectsPadding(string styleName, int? padding)
+    {
+        await using var recorder = new TestRecorder(App);
+
+        // FIXME: Tolerance needed because TextFieldAssist.TextBoxViewMargin is in play and slightly modifies the hint text placement in certain cases.
+        const double tolerance = 1.5;
+
+        string styleAttribute = $"Style=\"{{StaticResource {styleName}}}\"";
+        string paddingAttribute = padding.HasValue ? $"Padding=\"{padding.Value}\"" : string.Empty;
+
+        var datePicker = await LoadXaml<DatePicker>($@"
+<DatePicker {styleAttribute} {paddingAttribute}
+  materialDesign:HintAssist.Hint=""Hint text""
+  materialDesign:HintAssist.HelperText=""Helper text""
+  Width=""200"" VerticalAlignment=""Center"" HorizontalAlignment=""Center"" />
+");
+
+        var contentHost = await datePicker.GetElement<ScrollViewer>("PART_ContentHost");
+        var hint = await datePicker.GetElement<SmartHint>("Hint");
+        var helperText = await datePicker.GetElement<TextBlock>("HelperTextTextBlock");
+
+        Rect? contentHostCoordinates = await contentHost.GetCoordinates();
+        Rect? hintCoordinates = await hint.GetCoordinates();
+        Rect? helperTextCoordinates = await helperText.GetCoordinates();
+
+        Assert.InRange(Math.Abs(contentHostCoordinates.Value.Left - hintCoordinates.Value.Left), 0, tolerance);
+        Assert.InRange(Math.Abs(contentHostCoordinates.Value.Left - helperTextCoordinates.Value.Left), 0, tolerance);
+
+        recorder.Success();
+    }
+
+    [Theory]
+    [InlineData("MaterialDesignFloatingHintDatePicker", null)]
+    [InlineData("MaterialDesignFloatingHintDatePicker", 5)]
+    [InlineData("MaterialDesignFloatingHintDatePicker", 20)]
+    [InlineData("MaterialDesignFilledDatePicker", null)]
+    [InlineData("MaterialDesignFilledDatePicker", 5)]
+    [InlineData("MaterialDesignFilledDatePicker", 20)]
+    [InlineData("MaterialDesignOutlinedDatePicker", null)]
+    [InlineData("MaterialDesignOutlinedDatePicker", 5)]
+    [InlineData("MaterialDesignOutlinedDatePicker", 20)]
+    public async Task DatePicker_WithHintAndValidationError_RespectsPadding(string styleName, int? padding)
+    {
+        await using var recorder = new TestRecorder(App);
+
+        // FIXME: Tolerance needed because TextFieldAssist.TextBoxViewMargin is in play and slightly modifies the hint text placement in certain cases.
+        const double tolerance = 1.5;
+
+        string styleAttribute = $"Style=\"{{StaticResource {styleName}}}\"";
+        string paddingAttribute = padding.HasValue ? $"Padding=\"{padding.Value}\"" : string.Empty;
+
+        var datePicker = await LoadXaml<DatePicker>($@"
+<DatePicker {styleAttribute} {paddingAttribute}
+  materialDesign:HintAssist.Hint=""Hint text""
+  materialDesign:HintAssist.HelperText=""Helper text""
+  Width=""200"" VerticalAlignment=""Center"" HorizontalAlignment=""Center"">
+  <DatePicker.Text>
+    <Binding RelativeSource=""{{RelativeSource Self}}"" Path=""Tag"" UpdateSourceTrigger=""PropertyChanged"">
+      <Binding.ValidationRules>
+        <local:NotEmptyValidationRule ValidatesOnTargetUpdated=""True""/>
+      </Binding.ValidationRules>
+    </Binding>
+  </DatePicker.Text>
+</DatePicker>
+", ("local", typeof(NotEmptyValidationRule)));
+
+        var contentHost = await datePicker.GetElement<ScrollViewer>("PART_ContentHost");
+        var hint = await datePicker.GetElement<SmartHint>("Hint");
+        var errorViewer = await datePicker.GetElement<Border>("DefaultErrorViewer");
+
+        Rect? contentHostCoordinates = await contentHost.GetCoordinates();
+        Rect? hintCoordinates = await hint.GetCoordinates();
+        Rect? errorViewerCoordinates = await errorViewer.GetCoordinates();
+
+        Assert.InRange(Math.Abs(contentHostCoordinates.Value.Left - hintCoordinates.Value.Left), 0, tolerance);
+        Assert.InRange(Math.Abs(contentHostCoordinates.Value.Left - errorViewerCoordinates.Value.Left), 0, tolerance);
+
+        recorder.Success();
+    }
 }
 
 public class FutureDateValidationRule : ValidationRule