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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
//
// Description: Contains the DockPanel class.
// Spec at DockPanel.xml
//
using MS.Internal.PresentationFramework;
using MS.Internal.Telemetry.PresentationFramework;
using System.Windows.Media;
namespace System.Windows.Controls
{
#region Dock enum type
/// <summary>
/// Dock - Enum which describes how to position and stretch the child of a DockPanel.
/// </summary>
/// <seealso cref="DockPanel" />
public enum Dock
{
/// <summary>
/// Position this child at the left of the remaining space.
/// </summary>
Left,
/// <summary>
/// Position this child at the top of the remaining space.
/// </summary>
Top,
/// <summary>
/// Position this child at the right of the remaining space.
/// </summary>
Right,
/// <summary>
/// Position this child at the bottom of the remaining space.
/// </summary>
Bottom,
}
#endregion
/// <summary>
/// DockPanel is used to size and position children inward from the edges of available space.
///
/// A <see cref="System.Windows.Controls.Dock" /> enum (see <see cref="SetDock" /> and <see cref="GetDock" />)
/// determines on which size a child is placed. Children are stacked in order from these edges until
/// there is no more space; this happens when previous children have consumed all available space, or a child
/// with Dock set to Fill is encountered.
/// </summary>
public class DockPanel : Panel
{
//-------------------------------------------------------------------
//
// Constructors
//
//-------------------------------------------------------------------
#region Constructors
static DockPanel()
{
ControlsTraceLogger.AddControl(TelemetryControls.DockPanel);
}
/// <summary>
/// Default DependencyObject constructor
/// </summary>
/// <remarks>
/// Automatic determination of current Dispatcher. Use alternative constructor
/// that accepts a Dispatcher for best performance.
/// </remarks>
public DockPanel() : base()
{
}
#endregion
//-------------------------------------------------------------------
//
// Public Methods
//
//-------------------------------------------------------------------
#region Public Methods
/// <summary>
/// Reads the attached property Dock from the given element.
/// </summary>
/// <param name="element">UIElement from which to read the attached property.</param>
/// <returns>The property's value.</returns>
/// <seealso cref="DockPanel.DockProperty" />
[AttachedPropertyBrowsableForChildren()]
public static Dock GetDock(UIElement element)
{
ArgumentNullException.ThrowIfNull(element);
return (Dock) element.GetValue(DockProperty);
}
/// <summary>
/// Writes the attached property Dock to the given element.
/// </summary>
/// <param name="element">UIElement to which to write the attached property.</param>
/// <param name="dock">The property value to set</param>
/// <seealso cref="DockPanel.DockProperty" />
public static void SetDock(UIElement element, Dock dock)
{
ArgumentNullException.ThrowIfNull(element);
element.SetValue(DockProperty, dock);
}
private static void OnDockChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
UIElement uie = d as UIElement; //it may be anyting, like FlowDocument... bug 1237275
if(uie != null)
{
DockPanel p = VisualTreeHelper.GetParent(uie) as DockPanel;
if(p != null)
{
p.InvalidateMeasure();
}
}
}
#endregion
//-------------------------------------------------------------------
//
// Public Properties + Dependency Properties's
//
//-------------------------------------------------------------------
#region Public Properties
/// <summary>
/// This property controls whether the last child in the DockPanel should be stretched to fill any
/// remaining available space.
/// </summary>
public bool LastChildFill
{
get { return (bool) GetValue(LastChildFillProperty); }
set { SetValue(LastChildFillProperty, value); }
}
/// <summary>
/// DependencyProperty for <see cref="LastChildFill" /> property.
/// </summary>
[CommonDependencyProperty]
public static readonly DependencyProperty LastChildFillProperty =
DependencyProperty.Register(
"LastChildFill",
typeof(bool),
typeof(DockPanel),
new FrameworkPropertyMetadata(true, FrameworkPropertyMetadataOptions.AffectsArrange));
/// <summary>
/// DependencyProperty for Dock property.
/// </summary>
/// <seealso cref="DockPanel.GetDock" />
/// <seealso cref="DockPanel.SetDock" />
[CommonDependencyProperty]
public static readonly DependencyProperty DockProperty =
DependencyProperty.RegisterAttached(
"Dock",
typeof(Dock),
typeof(DockPanel),
new FrameworkPropertyMetadata(
Dock.Left,
new PropertyChangedCallback(OnDockChanged)),
new ValidateValueCallback(IsValidDock));
#endregion
//-------------------------------------------------------------------
//
// Protected Methods
//
//-------------------------------------------------------------------
#region Protected Methods
/// <summary>
/// Updates DesiredSize of the DockPanel. Called by parent UIElement. This is the first pass of layout.
/// </summary>
/// <remarks>
/// Children are measured based on their sizing properties and <see cref="System.Windows.Controls.Dock" />.
/// Each child is allowed to consume all of the space on the side on which it is docked; Left/Right docked
/// children are granted all vertical space for their entire width, and Top/Bottom docked children are
/// granted all horizontal space for their entire height.
/// </remarks>
/// <param name="constraint">Constraint size is an "upper limit" that the return value should not exceed.</param>
/// <returns>The Panel's desired size.</returns>
protected override Size MeasureOverride(Size constraint)
{
UIElementCollection children = InternalChildren;
double parentWidth = 0; // Our current required width due to children thus far.
double parentHeight = 0; // Our current required height due to children thus far.
double accumulatedWidth = 0; // Total width consumed by children.
double accumulatedHeight = 0; // Total height consumed by children.
for (int i = 0, count = children.Count; i < count; ++i)
{
UIElement child = children[i];
Size childConstraint; // Contains the suggested input constraint for this child.
Size childDesiredSize; // Contains the return size from child measure.
if (child == null) { continue; }
// Child constraint is the remaining size; this is total size minus size consumed by previous children.
childConstraint = new Size(Math.Max(0.0, constraint.Width - accumulatedWidth),
Math.Max(0.0, constraint.Height - accumulatedHeight));
// Measure child.
child.Measure(childConstraint);
childDesiredSize = child.DesiredSize;
// Now, we adjust:
// 1. Size consumed by children (accumulatedSize). This will be used when computing subsequent
// children to determine how much space is remaining for them.
// 2. Parent size implied by this child (parentSize) when added to the current children (accumulatedSize).
// This is different from the size above in one respect: A Dock.Left child implies a height, but does
// not actually consume any height for subsequent children.
// If we accumulate size in a given dimension, the next child (or the end conditions after the child loop)
// will deal with computing our minimum size (parentSize) due to that accumulation.
// Therefore, we only need to compute our minimum size (parentSize) in dimensions that this child does
// not accumulate: Width for Top/Bottom, Height for Left/Right.
switch (DockPanel.GetDock(child))
{
case Dock.Left:
case Dock.Right:
parentHeight = Math.Max(parentHeight, accumulatedHeight + childDesiredSize.Height);
accumulatedWidth += childDesiredSize.Width;
break;
case Dock.Top:
case Dock.Bottom:
parentWidth = Math.Max(parentWidth, accumulatedWidth + childDesiredSize.Width);
accumulatedHeight += childDesiredSize.Height;
break;
}
}
// Make sure the final accumulated size is reflected in parentSize.
parentWidth = Math.Max(parentWidth, accumulatedWidth);
parentHeight = Math.Max(parentHeight, accumulatedHeight);
return (new Size(parentWidth, parentHeight));
}
/// <summary>
/// DockPanel computes a position and final size for each of its children based upon their
/// <see cref="System.Windows.Controls.Dock" /> enum and sizing properties.
/// </summary>
/// <param name="arrangeSize">Size that DockPanel will assume to position children.</param>
protected override Size ArrangeOverride(Size arrangeSize)
{
UIElementCollection children = InternalChildren;
int totalChildrenCount = children.Count;
int nonFillChildrenCount = totalChildrenCount - (LastChildFill ? 1 : 0);
double accumulatedLeft = 0;
double accumulatedTop = 0;
double accumulatedRight = 0;
double accumulatedBottom = 0;
for (int i = 0; i < totalChildrenCount; ++i)
{
UIElement child = children[i];
if (child == null) { continue; }
Size childDesiredSize = child.DesiredSize;
Rect rcChild = new Rect(
accumulatedLeft,
accumulatedTop,
Math.Max(0.0, arrangeSize.Width - (accumulatedLeft + accumulatedRight)),
Math.Max(0.0, arrangeSize.Height - (accumulatedTop + accumulatedBottom)) );
if (i < nonFillChildrenCount)
{
switch (DockPanel.GetDock(child))
{
case Dock.Left:
accumulatedLeft += childDesiredSize.Width;
rcChild.Width = childDesiredSize.Width;
break;
case Dock.Right:
accumulatedRight += childDesiredSize.Width;
rcChild.X = Math.Max(0.0, arrangeSize.Width - accumulatedRight);
rcChild.Width = childDesiredSize.Width;
break;
case Dock.Top:
accumulatedTop += childDesiredSize.Height;
rcChild.Height = childDesiredSize.Height;
break;
case Dock.Bottom:
accumulatedBottom += childDesiredSize.Height;
rcChild.Y = Math.Max(0.0, arrangeSize.Height - accumulatedBottom);
rcChild.Height = childDesiredSize.Height;
break;
}
}
child.Arrange(rcChild);
}
return (arrangeSize);
}
#endregion Protected Methods
//-------------------------------------------------------------------
//
// Private Methods
//
//-------------------------------------------------------------------
#region Private Methods
internal static bool IsValidDock(object o)
{
Dock dock = (Dock)o;
return ( dock == Dock.Left
|| dock == Dock.Top
|| dock == Dock.Right
|| dock == Dock.Bottom);
}
//
// This property
// 1. Finds the correct initial size for the _effectiveValues store on the current DependencyObject
// 2. This is a performance optimization
//
internal override int EffectiveValuesInitialSize
{
get { return 9; }
}
#endregion Private Methods
}
}
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