// Licensed to the .NET Foundation under one or more agreements. // The .NET Foundation licenses this file to you under the MIT license. using System; using System.Collections.Generic; using System.ComponentModel; using System.Diagnostics; using System.Windows; using System.Windows.Controls; using System.Windows.Media; namespace Microsoft.Windows.Themes { /// <summary> /// A Border used to provide the default look of DataGrid headers. /// When Background or BorderBrush are set, the rendering will /// revert back to the default Border implementation. /// </summary> public sealed partial class DataGridHeaderBorder : Border { static DataGridHeaderBorder() { // We always set this to true on these borders, so just default it to true here. SnapsToDevicePixelsProperty.OverrideMetadata(typeof(DataGridHeaderBorder), new FrameworkPropertyMetadata(true)); } #region Header Appearance Properties /// <summary> /// Whether the hover look should be applied. /// </summary> public bool IsHovered { get { return (bool)GetValue(IsHoveredProperty); } set { SetValue(IsHoveredProperty, value); } } /// <summary> /// DependencyProperty for IsHovered. /// </summary> public static readonly DependencyProperty IsHoveredProperty = DependencyProperty.Register("IsHovered", typeof(bool), typeof(DataGridHeaderBorder), new FrameworkPropertyMetadata(false, FrameworkPropertyMetadataOptions.AffectsRender)); /// <summary> /// Whether the pressed look should be applied. /// </summary> public bool IsPressed { get { return (bool)GetValue(IsPressedProperty); } set { SetValue(IsPressedProperty, value); } } /// <summary> /// DependencyProperty for IsPressed. /// </summary> public static readonly DependencyProperty IsPressedProperty = DependencyProperty.Register("IsPressed", typeof(bool), typeof(DataGridHeaderBorder), new FrameworkPropertyMetadata(false, FrameworkPropertyMetadataOptions.AffectsRender | FrameworkPropertyMetadataOptions.AffectsArrange)); /// <summary> /// When false, will not apply the hover look even when IsHovered is true. /// </summary> public bool IsClickable { get { return (bool)GetValue(IsClickableProperty); } set { SetValue(IsClickableProperty, value); } } /// <summary> /// DependencyProperty for IsClickable. /// </summary> public static readonly DependencyProperty IsClickableProperty = DependencyProperty.Register("IsClickable", typeof(bool), typeof(DataGridHeaderBorder), new FrameworkPropertyMetadata(true, FrameworkPropertyMetadataOptions.AffectsRender | FrameworkPropertyMetadataOptions.AffectsArrange)); /// <summary> /// Whether to appear sorted. /// </summary> public ListSortDirection? SortDirection { get { return (ListSortDirection?)GetValue(SortDirectionProperty); } set { SetValue(SortDirectionProperty, value); } } /// <summary> /// DependencyProperty for SortDirection. /// </summary> public static readonly DependencyProperty SortDirectionProperty = DependencyProperty.Register("SortDirection", typeof(ListSortDirection?), typeof(DataGridHeaderBorder), new FrameworkPropertyMetadata(null, FrameworkPropertyMetadataOptions.AffectsRender)); /// <summary> /// Whether to appear selected. /// </summary> public bool IsSelected { get { return (bool)GetValue(IsSelectedProperty); } set { SetValue(IsSelectedProperty, value); } } /// <summary> /// DependencyProperty for IsSelected. /// </summary> public static readonly DependencyProperty IsSelectedProperty = DependencyProperty.Register("IsSelected", typeof(bool), typeof(DataGridHeaderBorder), new FrameworkPropertyMetadata(false, FrameworkPropertyMetadataOptions.AffectsRender)); /// <summary> /// Vertical = column header /// Horizontal = row header /// </summary> public Orientation Orientation { get { return (Orientation)GetValue(OrientationProperty); } set { SetValue(OrientationProperty, value); } } /// <summary> /// DependencyProperty for Orientation. /// </summary> public static readonly DependencyProperty OrientationProperty = DependencyProperty.Register("Orientation", typeof(Orientation), typeof(DataGridHeaderBorder), new FrameworkPropertyMetadata(Orientation.Vertical, FrameworkPropertyMetadataOptions.AffectsRender)); /// <summary> /// When there is a Background or BorderBrush, revert to the Border implementation. /// </summary> private bool UsingBorderImplementation { get { return (Background != null) || (BorderBrush != null); } } /// <summary> /// Property that indicates the brush to use when drawing seperators between headers. /// </summary> public Brush SeparatorBrush { get { return (Brush)GetValue(SeparatorBrushProperty); } set { SetValue(SeparatorBrushProperty, value); } } /// <summary> /// DependencyProperty for SeparatorBrush. /// </summary> public static readonly DependencyProperty SeparatorBrushProperty = DependencyProperty.Register("SeparatorBrush", typeof(Brush), typeof(DataGridHeaderBorder), new FrameworkPropertyMetadata(null)); /// <summary> /// Property that indicates the Visibility for the header seperators. /// </summary> public Visibility SeparatorVisibility { get { return (Visibility)GetValue(SeparatorVisibilityProperty); } set { SetValue(SeparatorVisibilityProperty, value); } } /// <summary> /// DependencyProperty for SeperatorBrush. /// </summary> public static readonly DependencyProperty SeparatorVisibilityProperty = DependencyProperty.Register("SeparatorVisibility", typeof(Visibility), typeof(DataGridHeaderBorder), new FrameworkPropertyMetadata(Visibility.Visible)); #endregion #region Layout /// <summary> /// Calculates the desired size of the element given the constraint. /// </summary> protected override Size MeasureOverride(Size constraint) { if (UsingBorderImplementation) { // Revert to the Border implementation return base.MeasureOverride(constraint); } UIElement child = Child; if (child != null) { // Use the public Padding property if it's set Thickness padding = Padding; if (padding.Equals(new Thickness())) { padding = DefaultPadding; } double childWidth = constraint.Width; double childHeight = constraint.Height; // If there is an actual constraint, then reserve space for the chrome if (!Double.IsInfinity(childWidth)) { childWidth = Math.Max(0.0, childWidth - padding.Left - padding.Right); } if (!Double.IsInfinity(childHeight)) { childHeight = Math.Max(0.0, childHeight - padding.Top - padding.Bottom); } child.Measure(new Size(childWidth, childHeight)); Size desiredSize = child.DesiredSize; // Add on the reserved space for the chrome return new Size(desiredSize.Width + padding.Left + padding.Right, desiredSize.Height + padding.Top + padding.Bottom); } return new Size(); } /// <summary> /// Positions children and returns the final size of the element. /// </summary> protected override Size ArrangeOverride(Size arrangeSize) { if (UsingBorderImplementation) { // Revert to the Border implementation return base.ArrangeOverride(arrangeSize); } UIElement child = Child; if (child != null) { // Use the public Padding property if it's set Thickness padding = Padding; if (padding.Equals(new Thickness())) { padding = DefaultPadding; } // Reserve space for the chrome double childWidth = Math.Max(0.0, arrangeSize.Width - padding.Left - padding.Right); double childHeight = Math.Max(0.0, arrangeSize.Height - padding.Top - padding.Bottom); child.Arrange(new Rect(padding.Left, padding.Top, childWidth, childHeight)); } return arrangeSize; } #endregion #region Rendering /// <summary> /// Returns a default padding for the various themes for use /// by measure and arrange. /// </summary> private Thickness DefaultPadding { get { Thickness padding = new Thickness(3.0); // The default padding Thickness? themePadding = ThemeDefaultPadding; if (themePadding == null) { if (Orientation == Orientation.Vertical) { // Reserve space to the right for the arrow padding.Right = 15.0; } } else { padding = (Thickness)themePadding; } // When pressed, offset the child if (IsPressed && IsClickable) { padding.Left += 1.0; padding.Top += 1.0; padding.Right -= 1.0; padding.Bottom -= 1.0; } return padding; } } /// <summary> /// Called when this element should re-render. /// </summary> protected override void OnRender(DrawingContext dc) { if (UsingBorderImplementation) { // Revert to the Border implementation base.OnRender(dc); } else { RenderTheme(dc); } } private static double Max0(double d) { return Math.Max(0.0, d); } #endregion #region Freezable Cache /// <summary> /// Creates a cache of frozen Freezable resources for use /// across all instances of the border. /// </summary> private static void EnsureCache(int size) { // Quick check to avoid locking if (_freezableCache == null) { lock (_cacheAccess) { // Re-check in case another thread created the cache if (_freezableCache == null) { _freezableCache = new List<Freezable>(size); for (int i = 0; i < size; i++) { _freezableCache.Add(null); } } } } Debug.Assert(_freezableCache.Count == size, "The cache size does not match the requested amount."); } /// <summary> /// Releases all resources in the cache. /// </summary> private static void ReleaseCache() { // Avoid locking if necessary if (_freezableCache != null) { lock (_cacheAccess) { // No need to re-check if non-null since it's OK to set it to null multiple times _freezableCache = null; } } } /// <summary> /// Retrieves a cached resource. /// </summary> private static Freezable GetCachedFreezable(int index) { lock (_cacheAccess) { Freezable freezable = _freezableCache[index]; Debug.Assert((freezable == null) || freezable.IsFrozen, "Cached Freezables should have been frozen."); return freezable; } } /// <summary> /// Caches a resources. /// </summary> private static void CacheFreezable(Freezable freezable, int index) { Debug.Assert(freezable.IsFrozen, "Cached Freezables should be frozen."); lock (_cacheAccess) { if (_freezableCache[index] == null) { _freezableCache[index] = freezable; } } } private static List<Freezable> _freezableCache; private static object _cacheAccess = new object(); #endregion } } |